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1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * lock.c
4 : : * POSTGRES primary lock mechanism
5 : : *
6 : : * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
7 : : * Portions Copyright (c) 1994, Regents of the University of California
8 : : *
9 : : *
10 : : * IDENTIFICATION
11 : : * src/backend/storage/lmgr/lock.c
12 : : *
13 : : * NOTES
14 : : * A lock table is a shared memory hash table. When
15 : : * a process tries to acquire a lock of a type that conflicts
16 : : * with existing locks, it is put to sleep using the routines
17 : : * in storage/lmgr/proc.c.
18 : : *
19 : : * For the most part, this code should be invoked via lmgr.c
20 : : * or another lock-management module, not directly.
21 : : *
22 : : * Interface:
23 : : *
24 : : * LockManagerShmemInit(), GetLocksMethodTable(), GetLockTagsMethodTable(),
25 : : * LockAcquire(), LockRelease(), LockReleaseAll(),
26 : : * LockCheckConflicts(), GrantLock()
27 : : *
28 : : *-------------------------------------------------------------------------
29 : : */
30 : : #include "postgres.h"
31 : :
32 : : #include <signal.h>
33 : : #include <unistd.h>
34 : :
35 : : #include "access/transam.h"
36 : : #include "access/twophase.h"
37 : : #include "access/twophase_rmgr.h"
38 : : #include "access/xlog.h"
39 : : #include "access/xlogutils.h"
40 : : #include "miscadmin.h"
41 : : #include "pg_trace.h"
42 : : #include "pgstat.h"
43 : : #include "storage/lmgr.h"
44 : : #include "storage/proc.h"
45 : : #include "storage/procarray.h"
46 : : #include "storage/shmem.h"
47 : : #include "storage/spin.h"
48 : : #include "storage/standby.h"
49 : : #include "storage/subsystems.h"
50 : : #include "utils/memutils.h"
51 : : #include "utils/ps_status.h"
52 : : #include "utils/resowner.h"
53 : :
54 : :
55 : : /* GUC variables */
56 : : int max_locks_per_xact; /* used to set the lock table size */
57 : : bool log_lock_failures = false;
58 : :
59 : : #define NLOCKENTS() \
60 : : mul_size(max_locks_per_xact, add_size(MaxBackends, max_prepared_xacts))
61 : :
62 : :
63 : : /*
64 : : * Data structures defining the semantics of the standard lock methods.
65 : : *
66 : : * The conflict table defines the semantics of the various lock modes.
67 : : */
68 : : static const LOCKMASK LockConflicts[] = {
69 : : 0,
70 : :
71 : : /* AccessShareLock */
72 : : LOCKBIT_ON(AccessExclusiveLock),
73 : :
74 : : /* RowShareLock */
75 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock),
76 : :
77 : : /* RowExclusiveLock */
78 : : LOCKBIT_ON(ShareLock) | LOCKBIT_ON(ShareRowExclusiveLock) |
79 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock),
80 : :
81 : : /* ShareUpdateExclusiveLock */
82 : : LOCKBIT_ON(ShareUpdateExclusiveLock) |
83 : : LOCKBIT_ON(ShareLock) | LOCKBIT_ON(ShareRowExclusiveLock) |
84 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock),
85 : :
86 : : /* ShareLock */
87 : : LOCKBIT_ON(RowExclusiveLock) | LOCKBIT_ON(ShareUpdateExclusiveLock) |
88 : : LOCKBIT_ON(ShareRowExclusiveLock) |
89 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock),
90 : :
91 : : /* ShareRowExclusiveLock */
92 : : LOCKBIT_ON(RowExclusiveLock) | LOCKBIT_ON(ShareUpdateExclusiveLock) |
93 : : LOCKBIT_ON(ShareLock) | LOCKBIT_ON(ShareRowExclusiveLock) |
94 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock),
95 : :
96 : : /* ExclusiveLock */
97 : : LOCKBIT_ON(RowShareLock) |
98 : : LOCKBIT_ON(RowExclusiveLock) | LOCKBIT_ON(ShareUpdateExclusiveLock) |
99 : : LOCKBIT_ON(ShareLock) | LOCKBIT_ON(ShareRowExclusiveLock) |
100 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock),
101 : :
102 : : /* AccessExclusiveLock */
103 : : LOCKBIT_ON(AccessShareLock) | LOCKBIT_ON(RowShareLock) |
104 : : LOCKBIT_ON(RowExclusiveLock) | LOCKBIT_ON(ShareUpdateExclusiveLock) |
105 : : LOCKBIT_ON(ShareLock) | LOCKBIT_ON(ShareRowExclusiveLock) |
106 : : LOCKBIT_ON(ExclusiveLock) | LOCKBIT_ON(AccessExclusiveLock)
107 : :
108 : : };
109 : :
110 : : /* Names of lock modes, for debug printouts */
111 : : static const char *const lock_mode_names[] =
112 : : {
113 : : "INVALID",
114 : : "AccessShareLock",
115 : : "RowShareLock",
116 : : "RowExclusiveLock",
117 : : "ShareUpdateExclusiveLock",
118 : : "ShareLock",
119 : : "ShareRowExclusiveLock",
120 : : "ExclusiveLock",
121 : : "AccessExclusiveLock"
122 : : };
123 : :
124 : : #ifndef LOCK_DEBUG
125 : : static bool Dummy_trace = false;
126 : : #endif
127 : :
128 : : static const LockMethodData default_lockmethod = {
129 : : MaxLockMode,
130 : : LockConflicts,
131 : : lock_mode_names,
132 : : #ifdef LOCK_DEBUG
133 : : &Trace_locks
134 : : #else
135 : : &Dummy_trace
136 : : #endif
137 : : };
138 : :
139 : : static const LockMethodData user_lockmethod = {
140 : : MaxLockMode,
141 : : LockConflicts,
142 : : lock_mode_names,
143 : : #ifdef LOCK_DEBUG
144 : : &Trace_userlocks
145 : : #else
146 : : &Dummy_trace
147 : : #endif
148 : : };
149 : :
150 : : /*
151 : : * map from lock method id to the lock table data structures
152 : : */
153 : : static const LockMethod LockMethods[] = {
154 : : NULL,
155 : : &default_lockmethod,
156 : : &user_lockmethod
157 : : };
158 : :
159 : :
160 : : /* Record that's written to 2PC state file when a lock is persisted */
161 : : typedef struct TwoPhaseLockRecord
162 : : {
163 : : LOCKTAG locktag;
164 : : LOCKMODE lockmode;
165 : : } TwoPhaseLockRecord;
166 : :
167 : :
168 : : /*
169 : : * Count of the number of fast path lock slots we believe to be used. This
170 : : * might be higher than the real number if another backend has transferred
171 : : * our locks to the primary lock table, but it can never be lower than the
172 : : * real value, since only we can acquire locks on our own behalf.
173 : : *
174 : : * XXX Allocate a static array of the maximum size. We could use a pointer
175 : : * and then allocate just the right size to save a couple kB, but then we
176 : : * would have to initialize that, while for the static array that happens
177 : : * automatically. Doesn't seem worth the extra complexity.
178 : : */
179 : : static int FastPathLocalUseCounts[FP_LOCK_GROUPS_PER_BACKEND_MAX];
180 : :
181 : : /*
182 : : * Flag to indicate if the relation extension lock is held by this backend.
183 : : * This flag is used to ensure that while holding the relation extension lock
184 : : * we don't try to acquire a heavyweight lock on any other object. This
185 : : * restriction implies that the relation extension lock won't ever participate
186 : : * in the deadlock cycle because we can never wait for any other heavyweight
187 : : * lock after acquiring this lock.
188 : : *
189 : : * Such a restriction is okay for relation extension locks as unlike other
190 : : * heavyweight locks these are not held till the transaction end. These are
191 : : * taken for a short duration to extend a particular relation and then
192 : : * released.
193 : : */
194 : : static bool IsRelationExtensionLockHeld PG_USED_FOR_ASSERTS_ONLY = false;
195 : :
196 : : /*
197 : : * Number of fast-path locks per backend - size of the arrays in PGPROC.
198 : : * This is set only once during start, before initializing shared memory,
199 : : * and remains constant after that.
200 : : *
201 : : * We set the limit based on max_locks_per_transaction GUC, because that's
202 : : * the best information about expected number of locks per backend we have.
203 : : * See InitializeFastPathLocks() for details.
204 : : */
205 : : int FastPathLockGroupsPerBackend = 0;
206 : :
207 : : /*
208 : : * Macros to calculate the fast-path group and index for a relation.
209 : : *
210 : : * The formula is a simple hash function, designed to spread the OIDs a bit,
211 : : * so that even contiguous values end up in different groups. In most cases
212 : : * there will be gaps anyway, but the multiplication should help a bit.
213 : : *
214 : : * The selected constant (49157) is a prime not too close to 2^k, and it's
215 : : * small enough to not cause overflows (in 64-bit).
216 : : *
217 : : * We can assume that FastPathLockGroupsPerBackend is a power-of-two per
218 : : * InitializeFastPathLocks().
219 : : */
220 : : #define FAST_PATH_REL_GROUP(rel) \
221 : : (((uint64) (rel) * 49157) & (FastPathLockGroupsPerBackend - 1))
222 : :
223 : : /*
224 : : * Given the group/slot indexes, calculate the slot index in the whole array
225 : : * of fast-path lock slots.
226 : : */
227 : : #define FAST_PATH_SLOT(group, index) \
228 : : (AssertMacro((uint32) (group) < FastPathLockGroupsPerBackend), \
229 : : AssertMacro((uint32) (index) < FP_LOCK_SLOTS_PER_GROUP), \
230 : : ((group) * FP_LOCK_SLOTS_PER_GROUP + (index)))
231 : :
232 : : /*
233 : : * Given a slot index (into the whole per-backend array), calculated using
234 : : * the FAST_PATH_SLOT macro, split it into group and index (in the group).
235 : : */
236 : : #define FAST_PATH_GROUP(index) \
237 : : (AssertMacro((uint32) (index) < FastPathLockSlotsPerBackend()), \
238 : : ((index) / FP_LOCK_SLOTS_PER_GROUP))
239 : : #define FAST_PATH_INDEX(index) \
240 : : (AssertMacro((uint32) (index) < FastPathLockSlotsPerBackend()), \
241 : : ((index) % FP_LOCK_SLOTS_PER_GROUP))
242 : :
243 : : /* Macros for manipulating proc->fpLockBits */
244 : : #define FAST_PATH_BITS_PER_SLOT 3
245 : : #define FAST_PATH_LOCKNUMBER_OFFSET 1
246 : : #define FAST_PATH_MASK ((1 << FAST_PATH_BITS_PER_SLOT) - 1)
247 : : #define FAST_PATH_BITS(proc, n) (proc)->fpLockBits[FAST_PATH_GROUP(n)]
248 : : #define FAST_PATH_GET_BITS(proc, n) \
249 : : ((FAST_PATH_BITS(proc, n) >> (FAST_PATH_BITS_PER_SLOT * FAST_PATH_INDEX(n))) & FAST_PATH_MASK)
250 : : #define FAST_PATH_BIT_POSITION(n, l) \
251 : : (AssertMacro((l) >= FAST_PATH_LOCKNUMBER_OFFSET), \
252 : : AssertMacro((l) < FAST_PATH_BITS_PER_SLOT+FAST_PATH_LOCKNUMBER_OFFSET), \
253 : : AssertMacro((n) < FastPathLockSlotsPerBackend()), \
254 : : ((l) - FAST_PATH_LOCKNUMBER_OFFSET + FAST_PATH_BITS_PER_SLOT * (FAST_PATH_INDEX(n))))
255 : : #define FAST_PATH_SET_LOCKMODE(proc, n, l) \
256 : : FAST_PATH_BITS(proc, n) |= UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l)
257 : : #define FAST_PATH_CLEAR_LOCKMODE(proc, n, l) \
258 : : FAST_PATH_BITS(proc, n) &= ~(UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l))
259 : : #define FAST_PATH_CHECK_LOCKMODE(proc, n, l) \
260 : : (FAST_PATH_BITS(proc, n) & (UINT64CONST(1) << FAST_PATH_BIT_POSITION(n, l)))
261 : :
262 : : /*
263 : : * The fast-path lock mechanism is concerned only with relation locks on
264 : : * unshared relations by backends bound to a database. The fast-path
265 : : * mechanism exists mostly to accelerate acquisition and release of locks
266 : : * that rarely conflict. Because ShareUpdateExclusiveLock is
267 : : * self-conflicting, it can't use the fast-path mechanism; but it also does
268 : : * not conflict with any of the locks that do, so we can ignore it completely.
269 : : */
270 : : #define EligibleForRelationFastPath(locktag, mode) \
271 : : ((locktag)->locktag_lockmethodid == DEFAULT_LOCKMETHOD && \
272 : : (locktag)->locktag_type == LOCKTAG_RELATION && \
273 : : (locktag)->locktag_field1 == MyDatabaseId && \
274 : : MyDatabaseId != InvalidOid && \
275 : : (mode) < ShareUpdateExclusiveLock)
276 : : #define ConflictsWithRelationFastPath(locktag, mode) \
277 : : ((locktag)->locktag_lockmethodid == DEFAULT_LOCKMETHOD && \
278 : : (locktag)->locktag_type == LOCKTAG_RELATION && \
279 : : (locktag)->locktag_field1 != InvalidOid && \
280 : : (mode) > ShareUpdateExclusiveLock)
281 : :
282 : : static bool FastPathGrantRelationLock(Oid relid, LOCKMODE lockmode);
283 : : static bool FastPathUnGrantRelationLock(Oid relid, LOCKMODE lockmode);
284 : : static bool FastPathTransferRelationLocks(LockMethod lockMethodTable,
285 : : const LOCKTAG *locktag, uint32 hashcode);
286 : : static PROCLOCK *FastPathGetRelationLockEntry(LOCALLOCK *locallock);
287 : :
288 : : /*
289 : : * To make the fast-path lock mechanism work, we must have some way of
290 : : * preventing the use of the fast-path when a conflicting lock might be present.
291 : : * We partition* the locktag space into FAST_PATH_STRONG_LOCK_HASH_PARTITIONS,
292 : : * and maintain an integer count of the number of "strong" lockers
293 : : * in each partition. When any "strong" lockers are present (which is
294 : : * hopefully not very often), the fast-path mechanism can't be used, and we
295 : : * must fall back to the slower method of pushing matching locks directly
296 : : * into the main lock tables.
297 : : *
298 : : * The deadlock detector does not know anything about the fast path mechanism,
299 : : * so any locks that might be involved in a deadlock must be transferred from
300 : : * the fast-path queues to the main lock table.
301 : : */
302 : :
303 : : #define FAST_PATH_STRONG_LOCK_HASH_BITS 10
304 : : #define FAST_PATH_STRONG_LOCK_HASH_PARTITIONS \
305 : : (1 << FAST_PATH_STRONG_LOCK_HASH_BITS)
306 : : #define FastPathStrongLockHashPartition(hashcode) \
307 : : ((hashcode) % FAST_PATH_STRONG_LOCK_HASH_PARTITIONS)
308 : :
309 : : typedef struct
310 : : {
311 : : slock_t mutex;
312 : : uint32 count[FAST_PATH_STRONG_LOCK_HASH_PARTITIONS];
313 : : } FastPathStrongRelationLockData;
314 : :
315 : : static FastPathStrongRelationLockData *FastPathStrongRelationLocks;
316 : :
317 : : static void LockManagerShmemRequest(void *arg);
318 : : static void LockManagerShmemInit(void *arg);
319 : :
320 : : const ShmemCallbacks LockManagerShmemCallbacks = {
321 : : .request_fn = LockManagerShmemRequest,
322 : : .init_fn = LockManagerShmemInit,
323 : : };
324 : :
325 : :
326 : : /*
327 : : * Pointers to hash tables containing lock state
328 : : *
329 : : * The LockMethodLockHash and LockMethodProcLockHash hash tables are in
330 : : * shared memory; LockMethodLocalHash is local to each backend.
331 : : */
332 : : static HTAB *LockMethodLockHash;
333 : : static HTAB *LockMethodProcLockHash;
334 : : static HTAB *LockMethodLocalHash;
335 : :
336 : :
337 : : /* private state for error cleanup */
338 : : static LOCALLOCK *StrongLockInProgress;
339 : : static LOCALLOCK *awaitedLock;
340 : : static ResourceOwner awaitedOwner;
341 : :
342 : :
343 : : #ifdef LOCK_DEBUG
344 : :
345 : : /*------
346 : : * The following configuration options are available for lock debugging:
347 : : *
348 : : * TRACE_LOCKS -- give a bunch of output what's going on in this file
349 : : * TRACE_USERLOCKS -- same but for user locks
350 : : * TRACE_LOCK_OIDMIN-- do not trace locks for tables below this oid
351 : : * (use to avoid output on system tables)
352 : : * TRACE_LOCK_TABLE -- trace locks on this table (oid) unconditionally
353 : : * DEBUG_DEADLOCKS -- currently dumps locks at untimely occasions ;)
354 : : *
355 : : * Furthermore, but in storage/lmgr/lwlock.c:
356 : : * TRACE_LWLOCKS -- trace lightweight locks (pretty useless)
357 : : *
358 : : * Define LOCK_DEBUG at compile time to get all these enabled.
359 : : * --------
360 : : */
361 : :
362 : : int Trace_lock_oidmin = FirstNormalObjectId;
363 : : bool Trace_locks = false;
364 : : bool Trace_userlocks = false;
365 : : int Trace_lock_table = 0;
366 : : bool Debug_deadlocks = false;
367 : :
368 : :
369 : : inline static bool
370 : : LOCK_DEBUG_ENABLED(const LOCKTAG *tag)
371 : : {
372 : : return
373 : : (*(LockMethods[tag->locktag_lockmethodid]->trace_flag) &&
374 : : ((Oid) tag->locktag_field2 >= (Oid) Trace_lock_oidmin))
375 : : || (Trace_lock_table &&
376 : : (tag->locktag_field2 == Trace_lock_table));
377 : : }
378 : :
379 : :
380 : : inline static void
381 : : LOCK_PRINT(const char *where, const LOCK *lock, LOCKMODE type)
382 : : {
383 : : if (LOCK_DEBUG_ENABLED(&lock->tag))
384 : : elog(LOG,
385 : : "%s: lock(%p) id(%u,%u,%u,%u,%u,%u) grantMask(%x) "
386 : : "req(%d,%d,%d,%d,%d,%d,%d)=%d "
387 : : "grant(%d,%d,%d,%d,%d,%d,%d)=%d wait(%d) type(%s)",
388 : : where, lock,
389 : : lock->tag.locktag_field1, lock->tag.locktag_field2,
390 : : lock->tag.locktag_field3, lock->tag.locktag_field4,
391 : : lock->tag.locktag_type, lock->tag.locktag_lockmethodid,
392 : : lock->grantMask,
393 : : lock->requested[1], lock->requested[2], lock->requested[3],
394 : : lock->requested[4], lock->requested[5], lock->requested[6],
395 : : lock->requested[7], lock->nRequested,
396 : : lock->granted[1], lock->granted[2], lock->granted[3],
397 : : lock->granted[4], lock->granted[5], lock->granted[6],
398 : : lock->granted[7], lock->nGranted,
399 : : dclist_count(&lock->waitProcs),
400 : : LockMethods[LOCK_LOCKMETHOD(*lock)]->lockModeNames[type]);
401 : : }
402 : :
403 : :
404 : : inline static void
405 : : PROCLOCK_PRINT(const char *where, const PROCLOCK *proclockP)
406 : : {
407 : : if (LOCK_DEBUG_ENABLED(&proclockP->tag.myLock->tag))
408 : : elog(LOG,
409 : : "%s: proclock(%p) lock(%p) method(%u) proc(%p) hold(%x)",
410 : : where, proclockP, proclockP->tag.myLock,
411 : : PROCLOCK_LOCKMETHOD(*(proclockP)),
412 : : proclockP->tag.myProc, (int) proclockP->holdMask);
413 : : }
414 : : #else /* not LOCK_DEBUG */
415 : :
416 : : #define LOCK_PRINT(where, lock, type) ((void) 0)
417 : : #define PROCLOCK_PRINT(where, proclockP) ((void) 0)
418 : : #endif /* not LOCK_DEBUG */
419 : :
420 : :
421 : : static uint32 proclock_hash(const void *key, Size keysize);
422 : : static void RemoveLocalLock(LOCALLOCK *locallock);
423 : : static PROCLOCK *SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc,
424 : : const LOCKTAG *locktag, uint32 hashcode, LOCKMODE lockmode);
425 : : static void GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner);
426 : : static void BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode);
427 : : static void FinishStrongLockAcquire(void);
428 : : static ProcWaitStatus WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner);
429 : : static void waitonlock_error_callback(void *arg);
430 : : static void ReleaseLockIfHeld(LOCALLOCK *locallock, bool sessionLock);
431 : : static void LockReassignOwner(LOCALLOCK *locallock, ResourceOwner parent);
432 : : static bool UnGrantLock(LOCK *lock, LOCKMODE lockmode,
433 : : PROCLOCK *proclock, LockMethod lockMethodTable);
434 : : static void CleanUpLock(LOCK *lock, PROCLOCK *proclock,
435 : : LockMethod lockMethodTable, uint32 hashcode,
436 : : bool wakeupNeeded);
437 : : static void LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
438 : : LOCKTAG *locktag, LOCKMODE lockmode,
439 : : bool decrement_strong_lock_count);
440 : : static void GetSingleProcBlockerStatusData(PGPROC *blocked_proc,
441 : : BlockedProcsData *data);
442 : :
443 : :
444 : : /*
445 : : * Register the lock manager's shmem data structures.
446 : : *
447 : : * In addition to this, each backend must also call InitLockManagerAccess() to
448 : : * create the locallock hash table.
449 : : */
450 : : static void
451 : 1271 : LockManagerShmemRequest(void *arg)
452 : : {
453 : : int64 max_table_size;
454 : :
455 : : /*
456 : : * Compute sizes for lock hashtables.
457 : : */
458 : 1271 : max_table_size = NLOCKENTS();
459 : :
460 : : /*
461 : : * Hash table for LOCK structs. This stores per-locked-object
462 : : * information.
463 : : */
464 : 1271 : ShmemRequestHash(.name = "LOCK hash",
465 : : .nelems = max_table_size,
466 : : .ptr = &LockMethodLockHash,
467 : : .hash_info.keysize = sizeof(LOCKTAG),
468 : : .hash_info.entrysize = sizeof(LOCK),
469 : : .hash_info.num_partitions = NUM_LOCK_PARTITIONS,
470 : : .hash_flags = HASH_ELEM | HASH_BLOBS | HASH_PARTITION,
471 : : );
472 : :
473 : : /* Assume an average of 2 holders per lock */
474 : 1271 : max_table_size *= 2;
475 : :
476 : 1271 : ShmemRequestHash(.name = "PROCLOCK hash",
477 : : .nelems = max_table_size,
478 : : .ptr = &LockMethodProcLockHash,
479 : : .hash_info.keysize = sizeof(PROCLOCKTAG),
480 : : .hash_info.entrysize = sizeof(PROCLOCK),
481 : : .hash_info.hash = proclock_hash,
482 : : .hash_info.num_partitions = NUM_LOCK_PARTITIONS,
483 : : .hash_flags = HASH_ELEM | HASH_FUNCTION | HASH_PARTITION,
484 : : );
485 : :
486 : 1271 : ShmemRequestStruct(.name = "Fast Path Strong Relation Lock Data",
487 : : .size = sizeof(FastPathStrongRelationLockData),
488 : : .ptr = (void **) (void *) &FastPathStrongRelationLocks,
489 : : );
490 : 1271 : }
491 : :
492 : : static void
493 : 1268 : LockManagerShmemInit(void *arg)
494 : : {
495 : 1268 : SpinLockInit(&FastPathStrongRelationLocks->mutex);
496 : 1268 : }
497 : :
498 : : /*
499 : : * Initialize the lock manager's backend-private data structures.
500 : : */
501 : : void
502 : 25262 : InitLockManagerAccess(void)
503 : : {
504 : : /*
505 : : * Allocate non-shared hash table for LOCALLOCK structs. This stores lock
506 : : * counts and resource owner information.
507 : : */
508 : : HASHCTL info;
509 : :
510 : 25262 : info.keysize = sizeof(LOCALLOCKTAG);
511 : 25262 : info.entrysize = sizeof(LOCALLOCK);
512 : :
513 : 25262 : LockMethodLocalHash = hash_create("LOCALLOCK hash",
514 : : 16,
515 : : &info,
516 : : HASH_ELEM | HASH_BLOBS);
517 : 25262 : }
518 : :
519 : :
520 : : /*
521 : : * Fetch the lock method table associated with a given lock
522 : : */
523 : : LockMethod
524 : 108 : GetLocksMethodTable(const LOCK *lock)
525 : : {
526 : 108 : LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*lock);
527 : :
528 : : Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
529 : 108 : return LockMethods[lockmethodid];
530 : : }
531 : :
532 : : /*
533 : : * Fetch the lock method table associated with a given locktag
534 : : */
535 : : LockMethod
536 : 1287 : GetLockTagsMethodTable(const LOCKTAG *locktag)
537 : : {
538 : 1287 : LOCKMETHODID lockmethodid = (LOCKMETHODID) locktag->locktag_lockmethodid;
539 : :
540 : : Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
541 : 1287 : return LockMethods[lockmethodid];
542 : : }
543 : :
544 : :
545 : : /*
546 : : * Compute the hash code associated with a LOCKTAG.
547 : : *
548 : : * To avoid unnecessary recomputations of the hash code, we try to do this
549 : : * just once per function, and then pass it around as needed. Aside from
550 : : * passing the hashcode to hash_search_with_hash_value(), we can extract
551 : : * the lock partition number from the hashcode.
552 : : */
553 : : uint32
554 : 25704084 : LockTagHashCode(const LOCKTAG *locktag)
555 : : {
556 : 25704084 : return get_hash_value(LockMethodLockHash, locktag);
557 : : }
558 : :
559 : : /*
560 : : * Compute the hash code associated with a PROCLOCKTAG.
561 : : *
562 : : * Because we want to use just one set of partition locks for both the
563 : : * LOCK and PROCLOCK hash tables, we have to make sure that PROCLOCKs
564 : : * fall into the same partition number as their associated LOCKs.
565 : : * dynahash.c expects the partition number to be the low-order bits of
566 : : * the hash code, and therefore a PROCLOCKTAG's hash code must have the
567 : : * same low-order bits as the associated LOCKTAG's hash code. We achieve
568 : : * this with this specialized hash function.
569 : : */
570 : : static uint32
571 : 823 : proclock_hash(const void *key, Size keysize)
572 : : {
573 : 823 : const PROCLOCKTAG *proclocktag = (const PROCLOCKTAG *) key;
574 : : uint32 lockhash;
575 : : Datum procptr;
576 : :
577 : : Assert(keysize == sizeof(PROCLOCKTAG));
578 : :
579 : : /* Look into the associated LOCK object, and compute its hash code */
580 : 823 : lockhash = LockTagHashCode(&proclocktag->myLock->tag);
581 : :
582 : : /*
583 : : * To make the hash code also depend on the PGPROC, we xor the proc
584 : : * struct's address into the hash code, left-shifted so that the
585 : : * partition-number bits don't change. Since this is only a hash, we
586 : : * don't care if we lose high-order bits of the address; use an
587 : : * intermediate variable to suppress cast-pointer-to-int warnings.
588 : : */
589 : 823 : procptr = PointerGetDatum(proclocktag->myProc);
590 : 823 : lockhash ^= DatumGetUInt32(procptr) << LOG2_NUM_LOCK_PARTITIONS;
591 : :
592 : 823 : return lockhash;
593 : : }
594 : :
595 : : /*
596 : : * Compute the hash code associated with a PROCLOCKTAG, given the hashcode
597 : : * for its underlying LOCK.
598 : : *
599 : : * We use this just to avoid redundant calls of LockTagHashCode().
600 : : */
601 : : static inline uint32
602 : 5778418 : ProcLockHashCode(const PROCLOCKTAG *proclocktag, uint32 hashcode)
603 : : {
604 : 5778418 : uint32 lockhash = hashcode;
605 : : Datum procptr;
606 : :
607 : : /*
608 : : * This must match proclock_hash()!
609 : : */
610 : 5778418 : procptr = PointerGetDatum(proclocktag->myProc);
611 : 5778418 : lockhash ^= DatumGetUInt32(procptr) << LOG2_NUM_LOCK_PARTITIONS;
612 : :
613 : 5778418 : return lockhash;
614 : : }
615 : :
616 : : /*
617 : : * Given two lock modes, return whether they would conflict.
618 : : */
619 : : bool
620 : 39025 : DoLockModesConflict(LOCKMODE mode1, LOCKMODE mode2)
621 : : {
622 : 39025 : LockMethod lockMethodTable = LockMethods[DEFAULT_LOCKMETHOD];
623 : :
624 [ + + ]: 39025 : if (lockMethodTable->conflictTab[mode1] & LOCKBIT_ON(mode2))
625 : 146 : return true;
626 : :
627 : 38879 : return false;
628 : : }
629 : :
630 : : /*
631 : : * LockHeldByMe -- test whether lock 'locktag' is held by the current
632 : : * transaction
633 : : *
634 : : * Returns true if current transaction holds a lock on 'tag' of mode
635 : : * 'lockmode'. If 'orstronger' is true, a stronger lockmode is also OK.
636 : : * ("Stronger" is defined as "numerically higher", which is a bit
637 : : * semantically dubious but is OK for the purposes we use this for.)
638 : : */
639 : : bool
640 : 2048340 : LockHeldByMe(const LOCKTAG *locktag,
641 : : LOCKMODE lockmode, bool orstronger)
642 : : {
643 : : LOCALLOCKTAG localtag;
644 : : LOCALLOCK *locallock;
645 : :
646 : : /*
647 : : * See if there is a LOCALLOCK entry for this lock and lockmode
648 : : */
649 [ + - - + : 2048340 : MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
- - - - -
- ]
650 : 2048340 : localtag.lock = *locktag;
651 : 2048340 : localtag.mode = lockmode;
652 : :
653 : 2048340 : locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
654 : : &localtag,
655 : : HASH_FIND, NULL);
656 : :
657 [ + + + - ]: 2048340 : if (locallock && locallock->nLocks > 0)
658 : 304017 : return true;
659 : :
660 [ + + ]: 1744323 : if (orstronger)
661 : : {
662 : : LOCKMODE slockmode;
663 : :
664 : 260216 : for (slockmode = lockmode + 1;
665 [ + + ]: 1744323 : slockmode <= MaxLockMode;
666 : 1484107 : slockmode++)
667 : : {
668 [ + + ]: 1642960 : if (LockHeldByMe(locktag, slockmode, false))
669 : 158853 : return true;
670 : : }
671 : : }
672 : :
673 : 1585470 : return false;
674 : : }
675 : :
676 : : #ifdef USE_ASSERT_CHECKING
677 : : /*
678 : : * GetLockMethodLocalHash -- return the hash of local locks, for modules that
679 : : * evaluate assertions based on all locks held.
680 : : */
681 : : HTAB *
682 : : GetLockMethodLocalHash(void)
683 : : {
684 : : return LockMethodLocalHash;
685 : : }
686 : : #endif
687 : :
688 : : /*
689 : : * LockHasWaiters -- look up 'locktag' and check if releasing this
690 : : * lock would wake up other processes waiting for it.
691 : : */
692 : : bool
693 : 0 : LockHasWaiters(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
694 : : {
695 : 0 : LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
696 : : LockMethod lockMethodTable;
697 : : LOCALLOCKTAG localtag;
698 : : LOCALLOCK *locallock;
699 : : LOCK *lock;
700 : : PROCLOCK *proclock;
701 : : LWLock *partitionLock;
702 : 0 : bool hasWaiters = false;
703 : :
704 [ # # # # ]: 0 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
705 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
706 : 0 : lockMethodTable = LockMethods[lockmethodid];
707 [ # # # # ]: 0 : if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
708 [ # # ]: 0 : elog(ERROR, "unrecognized lock mode: %d", lockmode);
709 : :
710 : : #ifdef LOCK_DEBUG
711 : : if (LOCK_DEBUG_ENABLED(locktag))
712 : : elog(LOG, "LockHasWaiters: lock [%u,%u] %s",
713 : : locktag->locktag_field1, locktag->locktag_field2,
714 : : lockMethodTable->lockModeNames[lockmode]);
715 : : #endif
716 : :
717 : : /*
718 : : * Find the LOCALLOCK entry for this lock and lockmode
719 : : */
720 [ # # # # : 0 : MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
# # # # #
# ]
721 : 0 : localtag.lock = *locktag;
722 : 0 : localtag.mode = lockmode;
723 : :
724 : 0 : locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
725 : : &localtag,
726 : : HASH_FIND, NULL);
727 : :
728 : : /*
729 : : * let the caller print its own error message, too. Do not ereport(ERROR).
730 : : */
731 [ # # # # ]: 0 : if (!locallock || locallock->nLocks <= 0)
732 : : {
733 [ # # ]: 0 : elog(WARNING, "you don't own a lock of type %s",
734 : : lockMethodTable->lockModeNames[lockmode]);
735 : 0 : return false;
736 : : }
737 : :
738 : : /*
739 : : * Check the shared lock table.
740 : : */
741 : 0 : partitionLock = LockHashPartitionLock(locallock->hashcode);
742 : :
743 : 0 : LWLockAcquire(partitionLock, LW_SHARED);
744 : :
745 : : /*
746 : : * We don't need to re-find the lock or proclock, since we kept their
747 : : * addresses in the locallock table, and they couldn't have been removed
748 : : * while we were holding a lock on them.
749 : : */
750 : 0 : lock = locallock->lock;
751 : : LOCK_PRINT("LockHasWaiters: found", lock, lockmode);
752 : 0 : proclock = locallock->proclock;
753 : : PROCLOCK_PRINT("LockHasWaiters: found", proclock);
754 : :
755 : : /*
756 : : * Double-check that we are actually holding a lock of the type we want to
757 : : * release.
758 : : */
759 [ # # ]: 0 : if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
760 : : {
761 : : PROCLOCK_PRINT("LockHasWaiters: WRONGTYPE", proclock);
762 : 0 : LWLockRelease(partitionLock);
763 [ # # ]: 0 : elog(WARNING, "you don't own a lock of type %s",
764 : : lockMethodTable->lockModeNames[lockmode]);
765 : 0 : RemoveLocalLock(locallock);
766 : 0 : return false;
767 : : }
768 : :
769 : : /*
770 : : * Do the checking.
771 : : */
772 [ # # ]: 0 : if ((lockMethodTable->conflictTab[lockmode] & lock->waitMask) != 0)
773 : 0 : hasWaiters = true;
774 : :
775 : 0 : LWLockRelease(partitionLock);
776 : :
777 : 0 : return hasWaiters;
778 : : }
779 : :
780 : : /*
781 : : * LockAcquire -- Check for lock conflicts, sleep if conflict found,
782 : : * set lock if/when no conflicts.
783 : : *
784 : : * Inputs:
785 : : * locktag: unique identifier for the lockable object
786 : : * lockmode: lock mode to acquire
787 : : * sessionLock: if true, acquire lock for session not current transaction
788 : : * dontWait: if true, don't wait to acquire lock
789 : : *
790 : : * Returns one of:
791 : : * LOCKACQUIRE_NOT_AVAIL lock not available, and dontWait=true
792 : : * LOCKACQUIRE_OK lock successfully acquired
793 : : * LOCKACQUIRE_ALREADY_HELD incremented count for lock already held
794 : : * LOCKACQUIRE_ALREADY_CLEAR incremented count for lock already clear
795 : : *
796 : : * In the normal case where dontWait=false and the caller doesn't need to
797 : : * distinguish a freshly acquired lock from one already taken earlier in
798 : : * this same transaction, there is no need to examine the return value.
799 : : *
800 : : * Side Effects: The lock is acquired and recorded in lock tables.
801 : : *
802 : : * NOTE: if we wait for the lock, there is no way to abort the wait
803 : : * short of aborting the transaction.
804 : : */
805 : : LockAcquireResult
806 : 1219214 : LockAcquire(const LOCKTAG *locktag,
807 : : LOCKMODE lockmode,
808 : : bool sessionLock,
809 : : bool dontWait)
810 : : {
811 : 1219214 : return LockAcquireExtended(locktag, lockmode, sessionLock, dontWait,
812 : : true, NULL, false);
813 : : }
814 : :
815 : : /*
816 : : * LockAcquireExtended - allows us to specify additional options
817 : : *
818 : : * reportMemoryError specifies whether a lock request that fills the lock
819 : : * table should generate an ERROR or not. Passing "false" allows the caller
820 : : * to attempt to recover from lock-table-full situations, perhaps by forcibly
821 : : * canceling other lock holders and then retrying. Note, however, that the
822 : : * return code for that is LOCKACQUIRE_NOT_AVAIL, so that it's unsafe to use
823 : : * in combination with dontWait = true, as the cause of failure couldn't be
824 : : * distinguished.
825 : : *
826 : : * If locallockp isn't NULL, *locallockp receives a pointer to the LOCALLOCK
827 : : * table entry if a lock is successfully acquired, or NULL if not.
828 : : *
829 : : * logLockFailure indicates whether to log details when a lock acquisition
830 : : * fails with dontWait = true.
831 : : */
832 : : LockAcquireResult
833 : 28049877 : LockAcquireExtended(const LOCKTAG *locktag,
834 : : LOCKMODE lockmode,
835 : : bool sessionLock,
836 : : bool dontWait,
837 : : bool reportMemoryError,
838 : : LOCALLOCK **locallockp,
839 : : bool logLockFailure)
840 : : {
841 : 28049877 : LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
842 : : LockMethod lockMethodTable;
843 : : LOCALLOCKTAG localtag;
844 : : LOCALLOCK *locallock;
845 : : LOCK *lock;
846 : : PROCLOCK *proclock;
847 : : bool found;
848 : : ResourceOwner owner;
849 : : uint32 hashcode;
850 : : LWLock *partitionLock;
851 : : bool found_conflict;
852 : : ProcWaitStatus waitResult;
853 : 28049877 : bool log_lock = false;
854 : :
855 [ + - - + ]: 28049877 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
856 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
857 : 28049877 : lockMethodTable = LockMethods[lockmethodid];
858 [ + - - + ]: 28049877 : if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
859 [ # # ]: 0 : elog(ERROR, "unrecognized lock mode: %d", lockmode);
860 : :
861 [ + + + + ]: 28049877 : if (RecoveryInProgress() && !InRecovery &&
862 [ + + ]: 397395 : (locktag->locktag_type == LOCKTAG_OBJECT ||
863 [ + - - + ]: 397395 : locktag->locktag_type == LOCKTAG_RELATION) &&
864 : : lockmode > RowExclusiveLock)
865 [ # # ]: 0 : ereport(ERROR,
866 : : (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
867 : : errmsg("cannot acquire lock mode %s on database objects while recovery is in progress",
868 : : lockMethodTable->lockModeNames[lockmode]),
869 : : errhint("Only RowExclusiveLock or less can be acquired on database objects during recovery.")));
870 : :
871 : : #ifdef LOCK_DEBUG
872 : : if (LOCK_DEBUG_ENABLED(locktag))
873 : : elog(LOG, "LockAcquire: lock [%u,%u] %s",
874 : : locktag->locktag_field1, locktag->locktag_field2,
875 : : lockMethodTable->lockModeNames[lockmode]);
876 : : #endif
877 : :
878 : : /* Identify owner for lock */
879 [ + + ]: 28049877 : if (sessionLock)
880 : 161613 : owner = NULL;
881 : : else
882 : 27888264 : owner = CurrentResourceOwner;
883 : :
884 : : /*
885 : : * Find or create a LOCALLOCK entry for this lock and lockmode
886 : : */
887 [ + - - + : 28049877 : MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
- - - - -
- ]
888 : 28049877 : localtag.lock = *locktag;
889 : 28049877 : localtag.mode = lockmode;
890 : :
891 : 28049877 : locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
892 : : &localtag,
893 : : HASH_ENTER, &found);
894 : :
895 : : /*
896 : : * if it's a new locallock object, initialize it
897 : : */
898 [ + + ]: 28049877 : if (!found)
899 : : {
900 : 24850792 : locallock->lock = NULL;
901 : 24850792 : locallock->proclock = NULL;
902 : 24850792 : locallock->hashcode = LockTagHashCode(&(localtag.lock));
903 : 24850792 : locallock->nLocks = 0;
904 : 24850792 : locallock->holdsStrongLockCount = false;
905 : 24850792 : locallock->lockCleared = false;
906 : 24850792 : locallock->numLockOwners = 0;
907 : 24850792 : locallock->maxLockOwners = 8;
908 : 24850792 : locallock->lockOwners = NULL; /* in case next line fails */
909 : 24850792 : locallock->lockOwners = (LOCALLOCKOWNER *)
910 : 24850792 : MemoryContextAlloc(TopMemoryContext,
911 : 24850792 : locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
912 : : }
913 : : else
914 : : {
915 : : /* Make sure there will be room to remember the lock */
916 [ - + ]: 3199085 : if (locallock->lockOwners == NULL)
917 : : {
918 : : /*
919 : : * A prior acquisition may leave the array unallocated after an
920 : : * out-of-memory failure.
921 : : */
922 : 0 : locallock->maxLockOwners = 8;
923 : 0 : locallock->lockOwners = (LOCALLOCKOWNER *)
924 : 0 : MemoryContextAlloc(TopMemoryContext,
925 : 0 : locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
926 : : }
927 [ + + ]: 3199085 : else if (locallock->numLockOwners >= locallock->maxLockOwners)
928 : : {
929 : 21 : int newsize = locallock->maxLockOwners * 2;
930 : :
931 : 21 : locallock->lockOwners = (LOCALLOCKOWNER *)
932 : 21 : repalloc(locallock->lockOwners,
933 : : newsize * sizeof(LOCALLOCKOWNER));
934 : 21 : locallock->maxLockOwners = newsize;
935 : : }
936 : : }
937 : 28049877 : hashcode = locallock->hashcode;
938 : :
939 [ + + ]: 28049877 : if (locallockp)
940 : 26830569 : *locallockp = locallock;
941 : :
942 : : /*
943 : : * If we already hold the lock, we can just increase the count locally.
944 : : *
945 : : * If lockCleared is already set, caller need not worry about absorbing
946 : : * sinval messages related to the lock's object.
947 : : */
948 [ + + ]: 28049877 : if (locallock->nLocks > 0)
949 : : {
950 : 3199085 : GrantLockLocal(locallock, owner);
951 [ + + ]: 3199085 : if (locallock->lockCleared)
952 : 3099186 : return LOCKACQUIRE_ALREADY_CLEAR;
953 : : else
954 : 99899 : return LOCKACQUIRE_ALREADY_HELD;
955 : : }
956 : :
957 : : /*
958 : : * We don't acquire any other heavyweight lock while holding the relation
959 : : * extension lock. We do allow to acquire the same relation extension
960 : : * lock more than once but that case won't reach here.
961 : : */
962 : : Assert(!IsRelationExtensionLockHeld);
963 : :
964 : : /*
965 : : * Prepare to emit a WAL record if acquisition of this lock needs to be
966 : : * replayed in a standby server.
967 : : *
968 : : * Here we prepare to log; after lock is acquired we'll issue log record.
969 : : * This arrangement simplifies error recovery in case the preparation step
970 : : * fails.
971 : : *
972 : : * Only AccessExclusiveLocks can conflict with lock types that read-only
973 : : * transactions can acquire in a standby server. Make sure this definition
974 : : * matches the one in GetRunningTransactionLocks().
975 : : */
976 [ + + ]: 24850792 : if (lockmode >= AccessExclusiveLock &&
977 [ + + ]: 322214 : locktag->locktag_type == LOCKTAG_RELATION &&
978 [ + + ]: 211719 : !RecoveryInProgress() &&
979 [ + + ]: 183445 : XLogStandbyInfoActive())
980 : : {
981 : 175783 : LogAccessExclusiveLockPrepare();
982 : 175783 : log_lock = true;
983 : : }
984 : :
985 : : /*
986 : : * Attempt to take lock via fast path, if eligible. But if we remember
987 : : * having filled up the fast path array, we don't attempt to make any
988 : : * further use of it until we release some locks. It's possible that some
989 : : * other backend has transferred some of those locks to the shared hash
990 : : * table, leaving space free, but it's not worth acquiring the LWLock just
991 : : * to check. It's also possible that we're acquiring a second or third
992 : : * lock type on a relation we have already locked using the fast-path, but
993 : : * for now we don't worry about that case either.
994 : : */
995 [ + + + + : 24850792 : if (EligibleForRelationFastPath(locktag, lockmode))
+ + + + +
+ ]
996 : : {
997 [ + + ]: 22278798 : if (FastPathLocalUseCounts[FAST_PATH_REL_GROUP(locktag->locktag_field2)] <
998 : : FP_LOCK_SLOTS_PER_GROUP)
999 : : {
1000 : 22184574 : uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
1001 : : bool acquired;
1002 : :
1003 : : /*
1004 : : * LWLockAcquire acts as a memory sequencing point, so it's safe
1005 : : * to assume that any strong locker whose increment to
1006 : : * FastPathStrongRelationLocks->counts becomes visible after we
1007 : : * test it has yet to begin to transfer fast-path locks.
1008 : : */
1009 : 22184574 : LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
1010 [ + + ]: 22184574 : if (FastPathStrongRelationLocks->count[fasthashcode] != 0)
1011 : 356025 : acquired = false;
1012 : : else
1013 : 21828549 : acquired = FastPathGrantRelationLock(locktag->locktag_field2,
1014 : : lockmode);
1015 : 22184574 : LWLockRelease(&MyProc->fpInfoLock);
1016 [ + + ]: 22184574 : if (acquired)
1017 : : {
1018 : : /*
1019 : : * The locallock might contain stale pointers to some old
1020 : : * shared objects; we MUST reset these to null before
1021 : : * considering the lock to be acquired via fast-path.
1022 : : */
1023 : 21828549 : locallock->lock = NULL;
1024 : 21828549 : locallock->proclock = NULL;
1025 : 21828549 : GrantLockLocal(locallock, owner);
1026 : 21828549 : return LOCKACQUIRE_OK;
1027 : : }
1028 : : }
1029 : : else
1030 : : {
1031 : : /*
1032 : : * Increment the lock statistics counter if lock could not be
1033 : : * acquired via the fast-path.
1034 : : */
1035 : 94224 : pgstat_count_lock_fastpath_exceeded(locallock->tag.lock.locktag_type);
1036 : : }
1037 : : }
1038 : :
1039 : : /*
1040 : : * If this lock could potentially have been taken via the fast-path by
1041 : : * some other backend, we must (temporarily) disable further use of the
1042 : : * fast-path for this lock tag, and migrate any locks already taken via
1043 : : * this method to the main lock table.
1044 : : */
1045 [ + + + + : 3022243 : if (ConflictsWithRelationFastPath(locktag, lockmode))
+ + + + ]
1046 : : {
1047 : 251906 : uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
1048 : :
1049 : 251906 : BeginStrongLockAcquire(locallock, fasthashcode);
1050 [ - + ]: 251906 : if (!FastPathTransferRelationLocks(lockMethodTable, locktag,
1051 : : hashcode))
1052 : : {
1053 : 0 : AbortStrongLockAcquire();
1054 [ # # ]: 0 : if (locallock->nLocks == 0)
1055 : 0 : RemoveLocalLock(locallock);
1056 [ # # ]: 0 : if (locallockp)
1057 : 0 : *locallockp = NULL;
1058 [ # # ]: 0 : if (reportMemoryError)
1059 [ # # ]: 0 : ereport(ERROR,
1060 : : (errcode(ERRCODE_OUT_OF_MEMORY),
1061 : : errmsg("out of shared memory"),
1062 : : errhint("You might need to increase \"%s\".", "max_locks_per_transaction")));
1063 : : else
1064 : 0 : return LOCKACQUIRE_NOT_AVAIL;
1065 : : }
1066 : : }
1067 : :
1068 : : /*
1069 : : * We didn't find the lock in our LOCALLOCK table, and we didn't manage to
1070 : : * take it via the fast-path, either, so we've got to mess with the shared
1071 : : * lock table.
1072 : : */
1073 : 3022243 : partitionLock = LockHashPartitionLock(hashcode);
1074 : :
1075 : 3022243 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
1076 : :
1077 : : /*
1078 : : * Find or create lock and proclock entries with this tag
1079 : : *
1080 : : * Note: if the locallock object already existed, it might have a pointer
1081 : : * to the lock already ... but we should not assume that that pointer is
1082 : : * valid, since a lock object with zero hold and request counts can go
1083 : : * away anytime. So we have to use SetupLockInTable() to recompute the
1084 : : * lock and proclock pointers, even if they're already set.
1085 : : */
1086 : 3022243 : proclock = SetupLockInTable(lockMethodTable, MyProc, locktag,
1087 : : hashcode, lockmode);
1088 [ - + ]: 3022243 : if (!proclock)
1089 : : {
1090 : 0 : AbortStrongLockAcquire();
1091 : 0 : LWLockRelease(partitionLock);
1092 [ # # ]: 0 : if (locallock->nLocks == 0)
1093 : 0 : RemoveLocalLock(locallock);
1094 [ # # ]: 0 : if (locallockp)
1095 : 0 : *locallockp = NULL;
1096 [ # # ]: 0 : if (reportMemoryError)
1097 [ # # ]: 0 : ereport(ERROR,
1098 : : (errcode(ERRCODE_OUT_OF_MEMORY),
1099 : : errmsg("out of shared memory"),
1100 : : errhint("You might need to increase \"%s\".", "max_locks_per_transaction")));
1101 : : else
1102 : 0 : return LOCKACQUIRE_NOT_AVAIL;
1103 : : }
1104 : 3022243 : locallock->proclock = proclock;
1105 : 3022243 : lock = proclock->tag.myLock;
1106 : 3022243 : locallock->lock = lock;
1107 : :
1108 : : /*
1109 : : * If lock requested conflicts with locks requested by waiters, must join
1110 : : * wait queue. Otherwise, check for conflict with already-held locks.
1111 : : * (That's last because most complex check.)
1112 : : */
1113 [ + + ]: 3022243 : if (lockMethodTable->conflictTab[lockmode] & lock->waitMask)
1114 : 196 : found_conflict = true;
1115 : : else
1116 : 3022047 : found_conflict = LockCheckConflicts(lockMethodTable, lockmode,
1117 : : lock, proclock);
1118 : :
1119 [ + + ]: 3022243 : if (!found_conflict)
1120 : : {
1121 : : /* No conflict with held or previously requested locks */
1122 : 3020025 : GrantLock(lock, proclock, lockmode);
1123 : 3020025 : waitResult = PROC_WAIT_STATUS_OK;
1124 : : }
1125 : : else
1126 : : {
1127 : : /*
1128 : : * Join the lock's wait queue. We call this even in the dontWait
1129 : : * case, because JoinWaitQueue() may discover that we can acquire the
1130 : : * lock immediately after all.
1131 : : */
1132 : 2218 : waitResult = JoinWaitQueue(locallock, lockMethodTable, dontWait);
1133 : : }
1134 : :
1135 [ + + ]: 3022243 : if (waitResult == PROC_WAIT_STATUS_ERROR)
1136 : : {
1137 : : /*
1138 : : * We're not getting the lock because a deadlock was detected already
1139 : : * while trying to join the wait queue, or because we would have to
1140 : : * wait but the caller requested no blocking.
1141 : : *
1142 : : * Undo the changes to shared entries before releasing the partition
1143 : : * lock.
1144 : : */
1145 : 732 : AbortStrongLockAcquire();
1146 : :
1147 [ + + ]: 732 : if (proclock->holdMask == 0)
1148 : : {
1149 : : uint32 proclock_hashcode;
1150 : :
1151 : 529 : proclock_hashcode = ProcLockHashCode(&proclock->tag,
1152 : : hashcode);
1153 : 529 : dlist_delete(&proclock->lockLink);
1154 : 529 : dlist_delete(&proclock->procLink);
1155 [ - + ]: 529 : if (!hash_search_with_hash_value(LockMethodProcLockHash,
1156 : 529 : &(proclock->tag),
1157 : : proclock_hashcode,
1158 : : HASH_REMOVE,
1159 : : NULL))
1160 [ # # ]: 0 : elog(PANIC, "proclock table corrupted");
1161 : : }
1162 : : else
1163 : : PROCLOCK_PRINT("LockAcquire: did not join wait queue", proclock);
1164 : 732 : lock->nRequested--;
1165 : 732 : lock->requested[lockmode]--;
1166 : : LOCK_PRINT("LockAcquire: did not join wait queue",
1167 : : lock, lockmode);
1168 : : Assert((lock->nRequested > 0) &&
1169 : : (lock->requested[lockmode] >= 0));
1170 : : Assert(lock->nGranted <= lock->nRequested);
1171 : 732 : LWLockRelease(partitionLock);
1172 [ + - ]: 732 : if (locallock->nLocks == 0)
1173 : 732 : RemoveLocalLock(locallock);
1174 : :
1175 [ + + ]: 732 : if (dontWait)
1176 : : {
1177 : : /*
1178 : : * Log lock holders and waiters as a detail log message if
1179 : : * logLockFailure = true and lock acquisition fails with dontWait
1180 : : * = true
1181 : : */
1182 [ - + ]: 731 : if (logLockFailure)
1183 : : {
1184 : : StringInfoData buf,
1185 : : lock_waiters_sbuf,
1186 : : lock_holders_sbuf;
1187 : : const char *modename;
1188 : 0 : int lockHoldersNum = 0;
1189 : :
1190 : 0 : initStringInfo(&buf);
1191 : 0 : initStringInfo(&lock_waiters_sbuf);
1192 : 0 : initStringInfo(&lock_holders_sbuf);
1193 : :
1194 : 0 : DescribeLockTag(&buf, &locallock->tag.lock);
1195 : 0 : modename = GetLockmodeName(locallock->tag.lock.locktag_lockmethodid,
1196 : : lockmode);
1197 : :
1198 : : /* Gather a list of all lock holders and waiters */
1199 : 0 : LWLockAcquire(partitionLock, LW_SHARED);
1200 : 0 : GetLockHoldersAndWaiters(locallock, &lock_holders_sbuf,
1201 : : &lock_waiters_sbuf, &lockHoldersNum);
1202 : 0 : LWLockRelease(partitionLock);
1203 : :
1204 [ # # ]: 0 : ereport(LOG,
1205 : : (errmsg("process %d could not obtain %s on %s",
1206 : : MyProcPid, modename, buf.data),
1207 : : errdetail_log_plural(
1208 : : "Process holding the lock: %s, Wait queue: %s.",
1209 : : "Processes holding the lock: %s, Wait queue: %s.",
1210 : : lockHoldersNum,
1211 : : lock_holders_sbuf.data,
1212 : : lock_waiters_sbuf.data)));
1213 : :
1214 : 0 : pfree(buf.data);
1215 : 0 : pfree(lock_holders_sbuf.data);
1216 : 0 : pfree(lock_waiters_sbuf.data);
1217 : : }
1218 [ + + ]: 731 : if (locallockp)
1219 : 222 : *locallockp = NULL;
1220 : 731 : return LOCKACQUIRE_NOT_AVAIL;
1221 : : }
1222 : : else
1223 : : {
1224 : 1 : DeadLockReport();
1225 : : /* DeadLockReport() will not return */
1226 : : }
1227 : : }
1228 : :
1229 : : /*
1230 : : * We are now in the lock queue, or the lock was already granted. If
1231 : : * queued, go to sleep.
1232 : : */
1233 [ + + ]: 3021511 : if (waitResult == PROC_WAIT_STATUS_WAITING)
1234 : : {
1235 : : Assert(!dontWait);
1236 : : PROCLOCK_PRINT("LockAcquire: sleeping on lock", proclock);
1237 : : LOCK_PRINT("LockAcquire: sleeping on lock", lock, lockmode);
1238 : 1481 : LWLockRelease(partitionLock);
1239 : :
1240 : 1481 : waitResult = WaitOnLock(locallock, owner);
1241 : :
1242 : : /*
1243 : : * NOTE: do not do any material change of state between here and
1244 : : * return. All required changes in locktable state must have been
1245 : : * done when the lock was granted to us --- see notes in WaitOnLock.
1246 : : */
1247 : :
1248 [ + + ]: 1436 : if (waitResult == PROC_WAIT_STATUS_ERROR)
1249 : : {
1250 : : /*
1251 : : * We failed as a result of a deadlock, see CheckDeadLock(). Quit
1252 : : * now.
1253 : : */
1254 : : Assert(!dontWait);
1255 : 5 : DeadLockReport();
1256 : : /* DeadLockReport() will not return */
1257 : : }
1258 : : }
1259 : : else
1260 : 3020030 : LWLockRelease(partitionLock);
1261 : : Assert(waitResult == PROC_WAIT_STATUS_OK);
1262 : :
1263 : : /* The lock was granted to us. Update the local lock entry accordingly */
1264 : : Assert((proclock->holdMask & LOCKBIT_ON(lockmode)) != 0);
1265 : 3021461 : GrantLockLocal(locallock, owner);
1266 : :
1267 : : /*
1268 : : * Lock state is fully up-to-date now; if we error out after this, no
1269 : : * special error cleanup is required.
1270 : : */
1271 : 3021461 : FinishStrongLockAcquire();
1272 : :
1273 : : /*
1274 : : * Emit a WAL record if acquisition of this lock needs to be replayed in a
1275 : : * standby server.
1276 : : */
1277 [ + + ]: 3021461 : if (log_lock)
1278 : : {
1279 : : /*
1280 : : * Decode the locktag back to the original values, to avoid sending
1281 : : * lots of empty bytes with every message. See lock.h to check how a
1282 : : * locktag is defined for LOCKTAG_RELATION
1283 : : */
1284 : 175570 : LogAccessExclusiveLock(locktag->locktag_field1,
1285 : 175570 : locktag->locktag_field2);
1286 : : }
1287 : :
1288 : 3021461 : return LOCKACQUIRE_OK;
1289 : : }
1290 : :
1291 : : /*
1292 : : * Find or create LOCK and PROCLOCK objects as needed for a new lock
1293 : : * request.
1294 : : *
1295 : : * Returns the PROCLOCK object, or NULL if we failed to create the objects
1296 : : * for lack of shared memory.
1297 : : *
1298 : : * The appropriate partition lock must be held at entry, and will be
1299 : : * held at exit.
1300 : : */
1301 : : static PROCLOCK *
1302 : 3024489 : SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc,
1303 : : const LOCKTAG *locktag, uint32 hashcode, LOCKMODE lockmode)
1304 : : {
1305 : : LOCK *lock;
1306 : : PROCLOCK *proclock;
1307 : : PROCLOCKTAG proclocktag;
1308 : : uint32 proclock_hashcode;
1309 : : bool found;
1310 : :
1311 : : /*
1312 : : * Find or create a lock with this tag.
1313 : : */
1314 : 3024489 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
1315 : : locktag,
1316 : : hashcode,
1317 : : HASH_ENTER_NULL,
1318 : : &found);
1319 [ - + ]: 3024489 : if (!lock)
1320 : 0 : return NULL;
1321 : :
1322 : : /*
1323 : : * if it's a new lock object, initialize it
1324 : : */
1325 [ + + ]: 3024489 : if (!found)
1326 : : {
1327 : 2712415 : lock->grantMask = 0;
1328 : 2712415 : lock->waitMask = 0;
1329 : 2712415 : dlist_init(&lock->procLocks);
1330 : 2712415 : dclist_init(&lock->waitProcs);
1331 : 2712415 : lock->nRequested = 0;
1332 : 2712415 : lock->nGranted = 0;
1333 [ + - + - : 16274490 : MemSet(lock->requested, 0, sizeof(int) * MAX_LOCKMODES);
+ - + - +
+ ]
1334 [ - + - - : 2712415 : MemSet(lock->granted, 0, sizeof(int) * MAX_LOCKMODES);
- - - - -
- ]
1335 : : LOCK_PRINT("LockAcquire: new", lock, lockmode);
1336 : : }
1337 : : else
1338 : : {
1339 : : LOCK_PRINT("LockAcquire: found", lock, lockmode);
1340 : : Assert((lock->nRequested >= 0) && (lock->requested[lockmode] >= 0));
1341 : : Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
1342 : : Assert(lock->nGranted <= lock->nRequested);
1343 : : }
1344 : :
1345 : : /*
1346 : : * Create the hash key for the proclock table.
1347 : : */
1348 : 3024489 : proclocktag.myLock = lock;
1349 : 3024489 : proclocktag.myProc = proc;
1350 : :
1351 : 3024489 : proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
1352 : :
1353 : : /*
1354 : : * Find or create a proclock entry with this tag
1355 : : */
1356 : 3024489 : proclock = (PROCLOCK *) hash_search_with_hash_value(LockMethodProcLockHash,
1357 : : &proclocktag,
1358 : : proclock_hashcode,
1359 : : HASH_ENTER_NULL,
1360 : : &found);
1361 [ - + ]: 3024489 : if (!proclock)
1362 : : {
1363 : : /* Oops, not enough shmem for the proclock */
1364 [ # # ]: 0 : if (lock->nRequested == 0)
1365 : : {
1366 : : /*
1367 : : * There are no other requestors of this lock, so garbage-collect
1368 : : * the lock object. We *must* do this to avoid a permanent leak
1369 : : * of shared memory, because there won't be anything to cause
1370 : : * anyone to release the lock object later.
1371 : : */
1372 : : Assert(dlist_is_empty(&(lock->procLocks)));
1373 [ # # ]: 0 : if (!hash_search_with_hash_value(LockMethodLockHash,
1374 : 0 : &(lock->tag),
1375 : : hashcode,
1376 : : HASH_REMOVE,
1377 : : NULL))
1378 [ # # ]: 0 : elog(PANIC, "lock table corrupted");
1379 : : }
1380 : 0 : return NULL;
1381 : : }
1382 : :
1383 : : /*
1384 : : * If new, initialize the new entry
1385 : : */
1386 [ + + ]: 3024489 : if (!found)
1387 : : {
1388 : 2750999 : uint32 partition = LockHashPartition(hashcode);
1389 : :
1390 : : /*
1391 : : * It might seem unsafe to access proclock->groupLeader without a
1392 : : * lock, but it's not really. Either we are initializing a proclock
1393 : : * on our own behalf, in which case our group leader isn't changing
1394 : : * because the group leader for a process can only ever be changed by
1395 : : * the process itself; or else we are transferring a fast-path lock to
1396 : : * the main lock table, in which case that process can't change its
1397 : : * lock group leader without first releasing all of its locks (and in
1398 : : * particular the one we are currently transferring).
1399 : : */
1400 : 5501998 : proclock->groupLeader = proc->lockGroupLeader != NULL ?
1401 [ + + ]: 2750999 : proc->lockGroupLeader : proc;
1402 : 2750999 : proclock->holdMask = 0;
1403 : 2750999 : proclock->releaseMask = 0;
1404 : : /* Add proclock to appropriate lists */
1405 : 2750999 : dlist_push_tail(&lock->procLocks, &proclock->lockLink);
1406 : 2750999 : dlist_push_tail(&proc->myProcLocks[partition], &proclock->procLink);
1407 : : PROCLOCK_PRINT("LockAcquire: new", proclock);
1408 : : }
1409 : : else
1410 : : {
1411 : : PROCLOCK_PRINT("LockAcquire: found", proclock);
1412 : : Assert((proclock->holdMask & ~lock->grantMask) == 0);
1413 : :
1414 : : #ifdef CHECK_DEADLOCK_RISK
1415 : :
1416 : : /*
1417 : : * Issue warning if we already hold a lower-level lock on this object
1418 : : * and do not hold a lock of the requested level or higher. This
1419 : : * indicates a deadlock-prone coding practice (eg, we'd have a
1420 : : * deadlock if another backend were following the same code path at
1421 : : * about the same time).
1422 : : *
1423 : : * This is not enabled by default, because it may generate log entries
1424 : : * about user-level coding practices that are in fact safe in context.
1425 : : * It can be enabled to help find system-level problems.
1426 : : *
1427 : : * XXX Doing numeric comparison on the lockmodes is a hack; it'd be
1428 : : * better to use a table. For now, though, this works.
1429 : : */
1430 : : {
1431 : : int i;
1432 : :
1433 : : for (i = lockMethodTable->numLockModes; i > 0; i--)
1434 : : {
1435 : : if (proclock->holdMask & LOCKBIT_ON(i))
1436 : : {
1437 : : if (i >= (int) lockmode)
1438 : : break; /* safe: we have a lock >= req level */
1439 : : elog(LOG, "deadlock risk: raising lock level"
1440 : : " from %s to %s on object %u/%u/%u",
1441 : : lockMethodTable->lockModeNames[i],
1442 : : lockMethodTable->lockModeNames[lockmode],
1443 : : lock->tag.locktag_field1, lock->tag.locktag_field2,
1444 : : lock->tag.locktag_field3);
1445 : : break;
1446 : : }
1447 : : }
1448 : : }
1449 : : #endif /* CHECK_DEADLOCK_RISK */
1450 : : }
1451 : :
1452 : : /*
1453 : : * lock->nRequested and lock->requested[] count the total number of
1454 : : * requests, whether granted or waiting, so increment those immediately.
1455 : : * The other counts don't increment till we get the lock.
1456 : : */
1457 : 3024489 : lock->nRequested++;
1458 : 3024489 : lock->requested[lockmode]++;
1459 : : Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
1460 : :
1461 : : /*
1462 : : * We shouldn't already hold the desired lock; else locallock table is
1463 : : * broken.
1464 : : */
1465 [ - + ]: 3024489 : if (proclock->holdMask & LOCKBIT_ON(lockmode))
1466 [ # # ]: 0 : elog(ERROR, "lock %s on object %u/%u/%u is already held",
1467 : : lockMethodTable->lockModeNames[lockmode],
1468 : : lock->tag.locktag_field1, lock->tag.locktag_field2,
1469 : : lock->tag.locktag_field3);
1470 : :
1471 : 3024489 : return proclock;
1472 : : }
1473 : :
1474 : : /*
1475 : : * Check and set/reset the flag that we hold the relation extension lock.
1476 : : *
1477 : : * It is callers responsibility that this function is called after
1478 : : * acquiring/releasing the relation extension lock.
1479 : : *
1480 : : * Pass acquired as true if lock is acquired, false otherwise.
1481 : : */
1482 : : static inline void
1483 : 50882147 : CheckAndSetLockHeld(LOCALLOCK *locallock, bool acquired)
1484 : : {
1485 : : #ifdef USE_ASSERT_CHECKING
1486 : : if (LOCALLOCK_LOCKTAG(*locallock) == LOCKTAG_RELATION_EXTEND)
1487 : : IsRelationExtensionLockHeld = acquired;
1488 : : #endif
1489 : 50882147 : }
1490 : :
1491 : : /*
1492 : : * Subroutine to free a locallock entry
1493 : : */
1494 : : static void
1495 : 24850792 : RemoveLocalLock(LOCALLOCK *locallock)
1496 : : {
1497 : : int i;
1498 : :
1499 [ + + ]: 24960267 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
1500 : : {
1501 [ + + ]: 109475 : if (locallock->lockOwners[i].owner != NULL)
1502 : 109415 : ResourceOwnerForgetLock(locallock->lockOwners[i].owner, locallock);
1503 : : }
1504 : 24850792 : locallock->numLockOwners = 0;
1505 [ + - ]: 24850792 : if (locallock->lockOwners != NULL)
1506 : 24850792 : pfree(locallock->lockOwners);
1507 : 24850792 : locallock->lockOwners = NULL;
1508 : :
1509 [ + + ]: 24850792 : if (locallock->holdsStrongLockCount)
1510 : : {
1511 : : uint32 fasthashcode;
1512 : :
1513 : 251575 : fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
1514 : :
1515 : 251575 : SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
1516 : : Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
1517 : 251575 : FastPathStrongRelationLocks->count[fasthashcode]--;
1518 : 251575 : locallock->holdsStrongLockCount = false;
1519 : 251575 : SpinLockRelease(&FastPathStrongRelationLocks->mutex);
1520 : : }
1521 : :
1522 [ - + ]: 24850792 : if (!hash_search(LockMethodLocalHash,
1523 : 24850792 : &(locallock->tag),
1524 : : HASH_REMOVE, NULL))
1525 [ # # ]: 0 : elog(WARNING, "locallock table corrupted");
1526 : :
1527 : : /*
1528 : : * Indicate that the lock is released for certain types of locks
1529 : : */
1530 : 24850792 : CheckAndSetLockHeld(locallock, false);
1531 : 24850792 : }
1532 : :
1533 : : /*
1534 : : * LockCheckConflicts -- test whether requested lock conflicts
1535 : : * with those already granted
1536 : : *
1537 : : * Returns true if conflict, false if no conflict.
1538 : : *
1539 : : * NOTES:
1540 : : * Here's what makes this complicated: one process's locks don't
1541 : : * conflict with one another, no matter what purpose they are held for
1542 : : * (eg, session and transaction locks do not conflict). Nor do the locks
1543 : : * of one process in a lock group conflict with those of another process in
1544 : : * the same group. So, we must subtract off these locks when determining
1545 : : * whether the requested new lock conflicts with those already held.
1546 : : */
1547 : : bool
1548 : 3023700 : LockCheckConflicts(LockMethod lockMethodTable,
1549 : : LOCKMODE lockmode,
1550 : : LOCK *lock,
1551 : : PROCLOCK *proclock)
1552 : : {
1553 : 3023700 : int numLockModes = lockMethodTable->numLockModes;
1554 : : LOCKMASK myLocks;
1555 : 3023700 : int conflictMask = lockMethodTable->conflictTab[lockmode];
1556 : : int conflictsRemaining[MAX_LOCKMODES];
1557 : 3023700 : int totalConflictsRemaining = 0;
1558 : : dlist_iter proclock_iter;
1559 : : int i;
1560 : :
1561 : : /*
1562 : : * first check for global conflicts: If no locks conflict with my request,
1563 : : * then I get the lock.
1564 : : *
1565 : : * Checking for conflict: lock->grantMask represents the types of
1566 : : * currently held locks. conflictTable[lockmode] has a bit set for each
1567 : : * type of lock that conflicts with request. Bitwise compare tells if
1568 : : * there is a conflict.
1569 : : */
1570 [ + + ]: 3023700 : if (!(conflictMask & lock->grantMask))
1571 : : {
1572 : : PROCLOCK_PRINT("LockCheckConflicts: no conflict", proclock);
1573 : 2899634 : return false;
1574 : : }
1575 : :
1576 : : /*
1577 : : * Rats. Something conflicts. But it could still be my own lock, or a
1578 : : * lock held by another member of my locking group. First, figure out how
1579 : : * many conflicts remain after subtracting out any locks I hold myself.
1580 : : */
1581 : 124066 : myLocks = proclock->holdMask;
1582 [ + + ]: 1116594 : for (i = 1; i <= numLockModes; i++)
1583 : : {
1584 [ + + ]: 992528 : if ((conflictMask & LOCKBIT_ON(i)) == 0)
1585 : : {
1586 : 522461 : conflictsRemaining[i] = 0;
1587 : 522461 : continue;
1588 : : }
1589 : 470067 : conflictsRemaining[i] = lock->granted[i];
1590 [ + + ]: 470067 : if (myLocks & LOCKBIT_ON(i))
1591 : 134114 : --conflictsRemaining[i];
1592 : 470067 : totalConflictsRemaining += conflictsRemaining[i];
1593 : : }
1594 : :
1595 : : /* If no conflicts remain, we get the lock. */
1596 [ + + ]: 124066 : if (totalConflictsRemaining == 0)
1597 : : {
1598 : : PROCLOCK_PRINT("LockCheckConflicts: resolved (simple)", proclock);
1599 : 121039 : return false;
1600 : : }
1601 : :
1602 : : /* If no group locking, it's definitely a conflict. */
1603 [ + + + + ]: 3027 : if (proclock->groupLeader == MyProc && MyProc->lockGroupLeader == NULL)
1604 : : {
1605 : : Assert(proclock->tag.myProc == MyProc);
1606 : : PROCLOCK_PRINT("LockCheckConflicts: conflicting (simple)",
1607 : : proclock);
1608 : 2015 : return true;
1609 : : }
1610 : :
1611 : : /*
1612 : : * The relation extension lock conflict even between the group members.
1613 : : */
1614 [ + + ]: 1012 : if (LOCK_LOCKTAG(*lock) == LOCKTAG_RELATION_EXTEND)
1615 : : {
1616 : : PROCLOCK_PRINT("LockCheckConflicts: conflicting (group)",
1617 : : proclock);
1618 : 18 : return true;
1619 : : }
1620 : :
1621 : : /*
1622 : : * Locks held in conflicting modes by members of our own lock group are
1623 : : * not real conflicts; we can subtract those out and see if we still have
1624 : : * a conflict. This is O(N) in the number of processes holding or
1625 : : * awaiting locks on this object. We could improve that by making the
1626 : : * shared memory state more complex (and larger) but it doesn't seem worth
1627 : : * it.
1628 : : */
1629 [ + - + + ]: 1759 : dlist_foreach(proclock_iter, &lock->procLocks)
1630 : : {
1631 : 1556 : PROCLOCK *otherproclock =
1632 : 1556 : dlist_container(PROCLOCK, lockLink, proclock_iter.cur);
1633 : :
1634 [ + + ]: 1556 : if (proclock != otherproclock &&
1635 [ + + ]: 1353 : proclock->groupLeader == otherproclock->groupLeader &&
1636 [ + + ]: 804 : (otherproclock->holdMask & conflictMask) != 0)
1637 : : {
1638 : 802 : int intersectMask = otherproclock->holdMask & conflictMask;
1639 : :
1640 [ + + ]: 7218 : for (i = 1; i <= numLockModes; i++)
1641 : : {
1642 [ + + ]: 6416 : if ((intersectMask & LOCKBIT_ON(i)) != 0)
1643 : : {
1644 [ - + ]: 815 : if (conflictsRemaining[i] <= 0)
1645 [ # # ]: 0 : elog(PANIC, "proclocks held do not match lock");
1646 : 815 : conflictsRemaining[i]--;
1647 : 815 : totalConflictsRemaining--;
1648 : : }
1649 : : }
1650 : :
1651 [ + + ]: 802 : if (totalConflictsRemaining == 0)
1652 : : {
1653 : : PROCLOCK_PRINT("LockCheckConflicts: resolved (group)",
1654 : : proclock);
1655 : 791 : return false;
1656 : : }
1657 : : }
1658 : : }
1659 : :
1660 : : /* Nope, it's a real conflict. */
1661 : : PROCLOCK_PRINT("LockCheckConflicts: conflicting (group)", proclock);
1662 : 203 : return true;
1663 : : }
1664 : :
1665 : : /*
1666 : : * GrantLock -- update the lock and proclock data structures to show
1667 : : * the lock request has been granted.
1668 : : *
1669 : : * NOTE: if proc was blocked, it also needs to be removed from the wait list
1670 : : * and have its waitLock/waitProcLock fields cleared. That's not done here.
1671 : : *
1672 : : * NOTE: the lock grant also has to be recorded in the associated LOCALLOCK
1673 : : * table entry; but since we may be awaking some other process, we can't do
1674 : : * that here; it's done by GrantLockLocal, instead.
1675 : : */
1676 : : void
1677 : 3023806 : GrantLock(LOCK *lock, PROCLOCK *proclock, LOCKMODE lockmode)
1678 : : {
1679 : 3023806 : lock->nGranted++;
1680 : 3023806 : lock->granted[lockmode]++;
1681 : 3023806 : lock->grantMask |= LOCKBIT_ON(lockmode);
1682 [ + + ]: 3023806 : if (lock->granted[lockmode] == lock->requested[lockmode])
1683 : 3023459 : lock->waitMask &= LOCKBIT_OFF(lockmode);
1684 : 3023806 : proclock->holdMask |= LOCKBIT_ON(lockmode);
1685 : : LOCK_PRINT("GrantLock", lock, lockmode);
1686 : : Assert((lock->nGranted > 0) && (lock->granted[lockmode] > 0));
1687 : : Assert(lock->nGranted <= lock->nRequested);
1688 : 3023806 : }
1689 : :
1690 : : /*
1691 : : * UnGrantLock -- opposite of GrantLock.
1692 : : *
1693 : : * Updates the lock and proclock data structures to show that the lock
1694 : : * is no longer held nor requested by the current holder.
1695 : : *
1696 : : * Returns true if there were any waiters waiting on the lock that
1697 : : * should now be woken up with ProcLockWakeup.
1698 : : */
1699 : : static bool
1700 : 3023720 : UnGrantLock(LOCK *lock, LOCKMODE lockmode,
1701 : : PROCLOCK *proclock, LockMethod lockMethodTable)
1702 : : {
1703 : 3023720 : bool wakeupNeeded = false;
1704 : :
1705 : : Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
1706 : : Assert((lock->nGranted > 0) && (lock->granted[lockmode] > 0));
1707 : : Assert(lock->nGranted <= lock->nRequested);
1708 : :
1709 : : /*
1710 : : * fix the general lock stats
1711 : : */
1712 : 3023720 : lock->nRequested--;
1713 : 3023720 : lock->requested[lockmode]--;
1714 : 3023720 : lock->nGranted--;
1715 : 3023720 : lock->granted[lockmode]--;
1716 : :
1717 [ + + ]: 3023720 : if (lock->granted[lockmode] == 0)
1718 : : {
1719 : : /* change the conflict mask. No more of this lock type. */
1720 : 2999950 : lock->grantMask &= LOCKBIT_OFF(lockmode);
1721 : : }
1722 : :
1723 : : LOCK_PRINT("UnGrantLock: updated", lock, lockmode);
1724 : :
1725 : : /*
1726 : : * We need only run ProcLockWakeup if the released lock conflicts with at
1727 : : * least one of the lock types requested by waiter(s). Otherwise whatever
1728 : : * conflict made them wait must still exist. NOTE: before MVCC, we could
1729 : : * skip wakeup if lock->granted[lockmode] was still positive. But that's
1730 : : * not true anymore, because the remaining granted locks might belong to
1731 : : * some waiter, who could now be awakened because he doesn't conflict with
1732 : : * his own locks.
1733 : : */
1734 [ + + ]: 3023720 : if (lockMethodTable->conflictTab[lockmode] & lock->waitMask)
1735 : 1394 : wakeupNeeded = true;
1736 : :
1737 : : /*
1738 : : * Now fix the per-proclock state.
1739 : : */
1740 : 3023720 : proclock->holdMask &= LOCKBIT_OFF(lockmode);
1741 : : PROCLOCK_PRINT("UnGrantLock: updated", proclock);
1742 : :
1743 : 3023720 : return wakeupNeeded;
1744 : : }
1745 : :
1746 : : /*
1747 : : * CleanUpLock -- clean up after releasing a lock. We garbage-collect the
1748 : : * proclock and lock objects if possible, and call ProcLockWakeup if there
1749 : : * are remaining requests and the caller says it's OK. (Normally, this
1750 : : * should be called after UnGrantLock, and wakeupNeeded is the result from
1751 : : * UnGrantLock.)
1752 : : *
1753 : : * The appropriate partition lock must be held at entry, and will be
1754 : : * held at exit.
1755 : : */
1756 : : static void
1757 : 2975388 : CleanUpLock(LOCK *lock, PROCLOCK *proclock,
1758 : : LockMethod lockMethodTable, uint32 hashcode,
1759 : : bool wakeupNeeded)
1760 : : {
1761 : : /*
1762 : : * If this was my last hold on this lock, delete my entry in the proclock
1763 : : * table.
1764 : : */
1765 [ + + ]: 2975388 : if (proclock->holdMask == 0)
1766 : : {
1767 : : uint32 proclock_hashcode;
1768 : :
1769 : : PROCLOCK_PRINT("CleanUpLock: deleting", proclock);
1770 : 2750480 : dlist_delete(&proclock->lockLink);
1771 : 2750480 : dlist_delete(&proclock->procLink);
1772 : 2750480 : proclock_hashcode = ProcLockHashCode(&proclock->tag, hashcode);
1773 [ - + ]: 2750480 : if (!hash_search_with_hash_value(LockMethodProcLockHash,
1774 : 2750480 : &(proclock->tag),
1775 : : proclock_hashcode,
1776 : : HASH_REMOVE,
1777 : : NULL))
1778 [ # # ]: 0 : elog(PANIC, "proclock table corrupted");
1779 : : }
1780 : :
1781 [ + + ]: 2975388 : if (lock->nRequested == 0)
1782 : : {
1783 : : /*
1784 : : * The caller just released the last lock, so garbage-collect the lock
1785 : : * object.
1786 : : */
1787 : : LOCK_PRINT("CleanUpLock: deleting", lock, 0);
1788 : : Assert(dlist_is_empty(&lock->procLocks));
1789 [ - + ]: 2712425 : if (!hash_search_with_hash_value(LockMethodLockHash,
1790 : 2712425 : &(lock->tag),
1791 : : hashcode,
1792 : : HASH_REMOVE,
1793 : : NULL))
1794 [ # # ]: 0 : elog(PANIC, "lock table corrupted");
1795 : : }
1796 [ + + ]: 262963 : else if (wakeupNeeded)
1797 : : {
1798 : : /* There are waiters on this lock, so wake them up. */
1799 : 1439 : ProcLockWakeup(lockMethodTable, lock);
1800 : : }
1801 : 2975388 : }
1802 : :
1803 : : /*
1804 : : * GrantLockLocal -- update the locallock data structures to show
1805 : : * the lock request has been granted.
1806 : : *
1807 : : * We expect that LockAcquire made sure there is room to add a new
1808 : : * ResourceOwner entry.
1809 : : */
1810 : : static void
1811 : 28049097 : GrantLockLocal(LOCALLOCK *locallock, ResourceOwner owner)
1812 : : {
1813 : 28049097 : LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
1814 : : int i;
1815 : :
1816 : : Assert(locallock->numLockOwners < locallock->maxLockOwners);
1817 : : /* Count the total */
1818 : 28049097 : locallock->nLocks++;
1819 : : /* Count the per-owner lock */
1820 [ + + ]: 29934867 : for (i = 0; i < locallock->numLockOwners; i++)
1821 : : {
1822 [ + + ]: 3903512 : if (lockOwners[i].owner == owner)
1823 : : {
1824 : 2017742 : lockOwners[i].nLocks++;
1825 : 2017742 : return;
1826 : : }
1827 : : }
1828 : 26031355 : lockOwners[i].owner = owner;
1829 : 26031355 : lockOwners[i].nLocks = 1;
1830 : 26031355 : locallock->numLockOwners++;
1831 [ + + ]: 26031355 : if (owner != NULL)
1832 : 25870271 : ResourceOwnerRememberLock(owner, locallock);
1833 : :
1834 : : /* Indicate that the lock is acquired for certain types of locks. */
1835 : 26031355 : CheckAndSetLockHeld(locallock, true);
1836 : : }
1837 : :
1838 : : /*
1839 : : * BeginStrongLockAcquire - inhibit use of fastpath for a given LOCALLOCK,
1840 : : * and arrange for error cleanup if it fails
1841 : : */
1842 : : static void
1843 : 251906 : BeginStrongLockAcquire(LOCALLOCK *locallock, uint32 fasthashcode)
1844 : : {
1845 : : Assert(StrongLockInProgress == NULL);
1846 : : Assert(locallock->holdsStrongLockCount == false);
1847 : :
1848 : : /*
1849 : : * Adding to a memory location is not atomic, so we take a spinlock to
1850 : : * ensure we don't collide with someone else trying to bump the count at
1851 : : * the same time.
1852 : : *
1853 : : * XXX: It might be worth considering using an atomic fetch-and-add
1854 : : * instruction here, on architectures where that is supported.
1855 : : */
1856 : :
1857 : 251906 : SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
1858 : 251906 : FastPathStrongRelationLocks->count[fasthashcode]++;
1859 : 251906 : locallock->holdsStrongLockCount = true;
1860 : 251906 : StrongLockInProgress = locallock;
1861 : 251906 : SpinLockRelease(&FastPathStrongRelationLocks->mutex);
1862 : 251906 : }
1863 : :
1864 : : /*
1865 : : * FinishStrongLockAcquire - cancel pending cleanup for a strong lock
1866 : : * acquisition once it's no longer needed
1867 : : */
1868 : : static void
1869 : 3021461 : FinishStrongLockAcquire(void)
1870 : : {
1871 : 3021461 : StrongLockInProgress = NULL;
1872 : 3021461 : }
1873 : :
1874 : : /*
1875 : : * AbortStrongLockAcquire - undo strong lock state changes performed by
1876 : : * BeginStrongLockAcquire.
1877 : : */
1878 : : void
1879 : 713749 : AbortStrongLockAcquire(void)
1880 : : {
1881 : : uint32 fasthashcode;
1882 : 713749 : LOCALLOCK *locallock = StrongLockInProgress;
1883 : :
1884 [ + + ]: 713749 : if (locallock == NULL)
1885 : 713536 : return;
1886 : :
1887 : 213 : fasthashcode = FastPathStrongLockHashPartition(locallock->hashcode);
1888 : : Assert(locallock->holdsStrongLockCount == true);
1889 : 213 : SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
1890 : : Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
1891 : 213 : FastPathStrongRelationLocks->count[fasthashcode]--;
1892 : 213 : locallock->holdsStrongLockCount = false;
1893 : 213 : StrongLockInProgress = NULL;
1894 : 213 : SpinLockRelease(&FastPathStrongRelationLocks->mutex);
1895 : : }
1896 : :
1897 : : /*
1898 : : * GrantAwaitedLock -- call GrantLockLocal for the lock we are doing
1899 : : * WaitOnLock on.
1900 : : *
1901 : : * proc.c needs this for the case where we are booted off the lock by
1902 : : * timeout, but discover that someone granted us the lock anyway.
1903 : : *
1904 : : * We could just export GrantLockLocal, but that would require including
1905 : : * resowner.h in lock.h, which creates circularity.
1906 : : */
1907 : : void
1908 : 2 : GrantAwaitedLock(void)
1909 : : {
1910 : 2 : GrantLockLocal(awaitedLock, awaitedOwner);
1911 : 2 : }
1912 : :
1913 : : /*
1914 : : * GetAwaitedLock -- Return the lock we're currently doing WaitOnLock on.
1915 : : */
1916 : : LOCALLOCK *
1917 : 713024 : GetAwaitedLock(void)
1918 : : {
1919 : 713024 : return awaitedLock;
1920 : : }
1921 : :
1922 : : /*
1923 : : * ResetAwaitedLock -- Forget that we are waiting on a lock.
1924 : : */
1925 : : void
1926 : 44 : ResetAwaitedLock(void)
1927 : : {
1928 : 44 : awaitedLock = NULL;
1929 : 44 : }
1930 : :
1931 : : /*
1932 : : * MarkLockClear -- mark an acquired lock as "clear"
1933 : : *
1934 : : * This means that we know we have absorbed all sinval messages that other
1935 : : * sessions generated before we acquired this lock, and so we can confidently
1936 : : * assume we know about any catalog changes protected by this lock.
1937 : : */
1938 : : void
1939 : 23863268 : MarkLockClear(LOCALLOCK *locallock)
1940 : : {
1941 : : Assert(locallock->nLocks > 0);
1942 : 23863268 : locallock->lockCleared = true;
1943 : 23863268 : }
1944 : :
1945 : : /*
1946 : : * WaitOnLock -- wait to acquire a lock
1947 : : *
1948 : : * This is a wrapper around ProcSleep, with extra tracing and bookkeeping.
1949 : : */
1950 : : static ProcWaitStatus
1951 : 1481 : WaitOnLock(LOCALLOCK *locallock, ResourceOwner owner)
1952 : : {
1953 : : ProcWaitStatus result;
1954 : : ErrorContextCallback waiterrcontext;
1955 : :
1956 : : TRACE_POSTGRESQL_LOCK_WAIT_START(locallock->tag.lock.locktag_field1,
1957 : : locallock->tag.lock.locktag_field2,
1958 : : locallock->tag.lock.locktag_field3,
1959 : : locallock->tag.lock.locktag_field4,
1960 : : locallock->tag.lock.locktag_type,
1961 : : locallock->tag.mode);
1962 : :
1963 : : /* Setup error traceback support for ereport() */
1964 : 1481 : waiterrcontext.callback = waitonlock_error_callback;
1965 : 1481 : waiterrcontext.arg = locallock;
1966 : 1481 : waiterrcontext.previous = error_context_stack;
1967 : 1481 : error_context_stack = &waiterrcontext;
1968 : :
1969 : : /* adjust the process title to indicate that it's waiting */
1970 : 1481 : set_ps_display_suffix("waiting");
1971 : :
1972 : : /*
1973 : : * Record the fact that we are waiting for a lock, so that
1974 : : * LockErrorCleanup will clean up if cancel/die happens.
1975 : : */
1976 : 1481 : awaitedLock = locallock;
1977 : 1481 : awaitedOwner = owner;
1978 : :
1979 : : /*
1980 : : * NOTE: Think not to put any shared-state cleanup after the call to
1981 : : * ProcSleep, in either the normal or failure path. The lock state must
1982 : : * be fully set by the lock grantor, or by CheckDeadLock if we give up
1983 : : * waiting for the lock. This is necessary because of the possibility
1984 : : * that a cancel/die interrupt will interrupt ProcSleep after someone else
1985 : : * grants us the lock, but before we've noticed it. Hence, after granting,
1986 : : * the locktable state must fully reflect the fact that we own the lock;
1987 : : * we can't do additional work on return.
1988 : : *
1989 : : * We can and do use a PG_TRY block to try to clean up after failure, but
1990 : : * this still has a major limitation: elog(FATAL) can occur while waiting
1991 : : * (eg, a "die" interrupt), and then control won't come back here. So all
1992 : : * cleanup of essential state should happen in LockErrorCleanup, not here.
1993 : : * We can use PG_TRY to clear the "waiting" status flags, since doing that
1994 : : * is unimportant if the process exits.
1995 : : */
1996 [ + + ]: 1481 : PG_TRY();
1997 : : {
1998 : 1481 : result = ProcSleep(locallock);
1999 : : }
2000 : 39 : PG_CATCH();
2001 : : {
2002 : : /* In this path, awaitedLock remains set until LockErrorCleanup */
2003 : :
2004 : : /* reset ps display to remove the suffix */
2005 : 39 : set_ps_display_remove_suffix();
2006 : :
2007 : : /* and propagate the error */
2008 : 39 : PG_RE_THROW();
2009 : : }
2010 [ - + ]: 1436 : PG_END_TRY();
2011 : :
2012 : : /*
2013 : : * We no longer want LockErrorCleanup to do anything.
2014 : : */
2015 : 1436 : awaitedLock = NULL;
2016 : :
2017 : : /* reset ps display to remove the suffix */
2018 : 1436 : set_ps_display_remove_suffix();
2019 : :
2020 : 1436 : error_context_stack = waiterrcontext.previous;
2021 : :
2022 : : TRACE_POSTGRESQL_LOCK_WAIT_DONE(locallock->tag.lock.locktag_field1,
2023 : : locallock->tag.lock.locktag_field2,
2024 : : locallock->tag.lock.locktag_field3,
2025 : : locallock->tag.lock.locktag_field4,
2026 : : locallock->tag.lock.locktag_type,
2027 : : locallock->tag.mode);
2028 : :
2029 : 1436 : return result;
2030 : : }
2031 : :
2032 : : /*
2033 : : * error context callback for failures in WaitOnLock
2034 : : *
2035 : : * We report which lock was being waited on, in the same style used in
2036 : : * deadlock reports. This helps with lock timeout errors in particular.
2037 : : */
2038 : : static void
2039 : 229 : waitonlock_error_callback(void *arg)
2040 : : {
2041 : 229 : LOCALLOCK *locallock = (LOCALLOCK *) arg;
2042 : 229 : const LOCKTAG *tag = &locallock->tag.lock;
2043 : 229 : LOCKMODE mode = locallock->tag.mode;
2044 : : StringInfoData locktagbuf;
2045 : :
2046 : 229 : initStringInfo(&locktagbuf);
2047 : 229 : DescribeLockTag(&locktagbuf, tag);
2048 : :
2049 : 458 : errcontext("waiting for %s on %s",
2050 : 229 : GetLockmodeName(tag->locktag_lockmethodid, mode),
2051 : : locktagbuf.data);
2052 : 229 : }
2053 : :
2054 : : /*
2055 : : * Remove a proc from the wait-queue it is on (caller must know it is on one).
2056 : : * This is only used when the proc has failed to get the lock, so we set its
2057 : : * waitStatus to PROC_WAIT_STATUS_ERROR.
2058 : : *
2059 : : * Appropriate partition lock must be held by caller. Also, caller is
2060 : : * responsible for signaling the proc if needed.
2061 : : *
2062 : : * NB: this does not clean up any locallock object that may exist for the lock.
2063 : : */
2064 : : void
2065 : 47 : RemoveFromWaitQueue(PGPROC *proc, uint32 hashcode)
2066 : : {
2067 : 47 : LOCK *waitLock = proc->waitLock;
2068 : 47 : PROCLOCK *proclock = proc->waitProcLock;
2069 : 47 : LOCKMODE lockmode = proc->waitLockMode;
2070 : 47 : LOCKMETHODID lockmethodid = LOCK_LOCKMETHOD(*waitLock);
2071 : :
2072 : : /* Make sure proc is waiting */
2073 : : Assert(proc->waitStatus == PROC_WAIT_STATUS_WAITING);
2074 : : Assert(!dlist_node_is_detached(&proc->waitLink));
2075 : : Assert(waitLock);
2076 : : Assert(!dclist_is_empty(&waitLock->waitProcs));
2077 : : Assert(0 < lockmethodid && lockmethodid < lengthof(LockMethods));
2078 : :
2079 : : /* Remove proc from lock's wait queue */
2080 : 47 : dclist_delete_from_thoroughly(&waitLock->waitProcs, &proc->waitLink);
2081 : :
2082 : : /* Undo increments of request counts by waiting process */
2083 : : Assert(waitLock->nRequested > 0);
2084 : : Assert(waitLock->nRequested > proc->waitLock->nGranted);
2085 : 47 : waitLock->nRequested--;
2086 : : Assert(waitLock->requested[lockmode] > 0);
2087 : 47 : waitLock->requested[lockmode]--;
2088 : : /* don't forget to clear waitMask bit if appropriate */
2089 [ + - ]: 47 : if (waitLock->granted[lockmode] == waitLock->requested[lockmode])
2090 : 47 : waitLock->waitMask &= LOCKBIT_OFF(lockmode);
2091 : :
2092 : : /* Clean up the proc's own state, and pass it the ok/fail signal */
2093 : 47 : proc->waitLock = NULL;
2094 : 47 : proc->waitProcLock = NULL;
2095 : 47 : proc->waitStatus = PROC_WAIT_STATUS_ERROR;
2096 : :
2097 : : /*
2098 : : * Delete the proclock immediately if it represents no already-held locks.
2099 : : * (This must happen now because if the owner of the lock decides to
2100 : : * release it, and the requested/granted counts then go to zero,
2101 : : * LockRelease expects there to be no remaining proclocks.) Then see if
2102 : : * any other waiters for the lock can be woken up now.
2103 : : */
2104 : 47 : CleanUpLock(waitLock, proclock,
2105 : 47 : LockMethods[lockmethodid], hashcode,
2106 : : true);
2107 : 47 : }
2108 : :
2109 : : /*
2110 : : * LockRelease -- look up 'locktag' and release one 'lockmode' lock on it.
2111 : : * Release a session lock if 'sessionLock' is true, else release a
2112 : : * regular transaction lock.
2113 : : *
2114 : : * Side Effects: find any waiting processes that are now wakable,
2115 : : * grant them their requested locks and awaken them.
2116 : : * (We have to grant the lock here to avoid a race between
2117 : : * the waking process and any new process to
2118 : : * come along and request the lock.)
2119 : : */
2120 : : bool
2121 : 24871566 : LockRelease(const LOCKTAG *locktag, LOCKMODE lockmode, bool sessionLock)
2122 : : {
2123 : 24871566 : LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
2124 : : LockMethod lockMethodTable;
2125 : : LOCALLOCKTAG localtag;
2126 : : LOCALLOCK *locallock;
2127 : : LOCK *lock;
2128 : : PROCLOCK *proclock;
2129 : : LWLock *partitionLock;
2130 : : bool wakeupNeeded;
2131 : :
2132 [ + - - + ]: 24871566 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2133 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2134 : 24871566 : lockMethodTable = LockMethods[lockmethodid];
2135 [ + - - + ]: 24871566 : if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
2136 [ # # ]: 0 : elog(ERROR, "unrecognized lock mode: %d", lockmode);
2137 : :
2138 : : #ifdef LOCK_DEBUG
2139 : : if (LOCK_DEBUG_ENABLED(locktag))
2140 : : elog(LOG, "LockRelease: lock [%u,%u] %s",
2141 : : locktag->locktag_field1, locktag->locktag_field2,
2142 : : lockMethodTable->lockModeNames[lockmode]);
2143 : : #endif
2144 : :
2145 : : /*
2146 : : * Find the LOCALLOCK entry for this lock and lockmode
2147 : : */
2148 [ + - - + : 24871566 : MemSet(&localtag, 0, sizeof(localtag)); /* must clear padding */
- - - - -
- ]
2149 : 24871566 : localtag.lock = *locktag;
2150 : 24871566 : localtag.mode = lockmode;
2151 : :
2152 : 24871566 : locallock = (LOCALLOCK *) hash_search(LockMethodLocalHash,
2153 : : &localtag,
2154 : : HASH_FIND, NULL);
2155 : :
2156 : : /*
2157 : : * let the caller print its own error message, too. Do not ereport(ERROR).
2158 : : */
2159 [ + + - + ]: 24871566 : if (!locallock || locallock->nLocks <= 0)
2160 : : {
2161 [ + - ]: 17 : elog(WARNING, "you don't own a lock of type %s",
2162 : : lockMethodTable->lockModeNames[lockmode]);
2163 : 17 : return false;
2164 : : }
2165 : :
2166 : : /*
2167 : : * Decrease the count for the resource owner.
2168 : : */
2169 : : {
2170 : 24871549 : LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
2171 : : ResourceOwner owner;
2172 : : int i;
2173 : :
2174 : : /* Identify owner for lock */
2175 [ + + ]: 24871549 : if (sessionLock)
2176 : 161063 : owner = NULL;
2177 : : else
2178 : 24710486 : owner = CurrentResourceOwner;
2179 : :
2180 [ + + ]: 24872788 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
2181 : : {
2182 [ + + ]: 24872772 : if (lockOwners[i].owner == owner)
2183 : : {
2184 : : Assert(lockOwners[i].nLocks > 0);
2185 [ + + ]: 24871533 : if (--lockOwners[i].nLocks == 0)
2186 : : {
2187 [ + + ]: 24100077 : if (owner != NULL)
2188 : 23939053 : ResourceOwnerForgetLock(owner, locallock);
2189 : : /* compact out unused slot */
2190 : 24100077 : locallock->numLockOwners--;
2191 [ + + ]: 24100077 : if (i < locallock->numLockOwners)
2192 : 89 : lockOwners[i] = lockOwners[locallock->numLockOwners];
2193 : : }
2194 : 24871533 : break;
2195 : : }
2196 : : }
2197 [ + + ]: 24871549 : if (i < 0)
2198 : : {
2199 : : /* don't release a lock belonging to another owner */
2200 [ + - ]: 16 : elog(WARNING, "you don't own a lock of type %s",
2201 : : lockMethodTable->lockModeNames[lockmode]);
2202 : 16 : return false;
2203 : : }
2204 : : }
2205 : :
2206 : : /*
2207 : : * Decrease the total local count. If we're still holding the lock, we're
2208 : : * done.
2209 : : */
2210 : 24871533 : locallock->nLocks--;
2211 : :
2212 [ + + ]: 24871533 : if (locallock->nLocks > 0)
2213 : 1660312 : return true;
2214 : :
2215 : : /*
2216 : : * At this point we can no longer suppose we are clear of invalidation
2217 : : * messages related to this lock. Although we'll delete the LOCALLOCK
2218 : : * object before any intentional return from this routine, it seems worth
2219 : : * the trouble to explicitly reset lockCleared right now, just in case
2220 : : * some error prevents us from deleting the LOCALLOCK.
2221 : : */
2222 : 23211221 : locallock->lockCleared = false;
2223 : :
2224 : : /* Attempt fast release of any lock eligible for the fast path. */
2225 [ + + + + : 23211221 : if (EligibleForRelationFastPath(locktag, lockmode) &&
+ + + + +
+ ]
2226 [ + + ]: 21415194 : FastPathLocalUseCounts[FAST_PATH_REL_GROUP(locktag->locktag_field2)] > 0)
2227 : : {
2228 : : bool released;
2229 : :
2230 : : /*
2231 : : * We might not find the lock here, even if we originally entered it
2232 : : * here. Another backend may have moved it to the main table.
2233 : : */
2234 : 21109870 : LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
2235 : 21109870 : released = FastPathUnGrantRelationLock(locktag->locktag_field2,
2236 : : lockmode);
2237 : 21109870 : LWLockRelease(&MyProc->fpInfoLock);
2238 [ + + ]: 21109870 : if (released)
2239 : : {
2240 : 20990962 : RemoveLocalLock(locallock);
2241 : 20990962 : return true;
2242 : : }
2243 : : }
2244 : :
2245 : : /*
2246 : : * Otherwise we've got to mess with the shared lock table.
2247 : : */
2248 : 2220259 : partitionLock = LockHashPartitionLock(locallock->hashcode);
2249 : :
2250 : 2220259 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2251 : :
2252 : : /*
2253 : : * Normally, we don't need to re-find the lock or proclock, since we kept
2254 : : * their addresses in the locallock table, and they couldn't have been
2255 : : * removed while we were holding a lock on them. But it's possible that
2256 : : * the lock was taken fast-path and has since been moved to the main hash
2257 : : * table by another backend, in which case we will need to look up the
2258 : : * objects here. We assume the lock field is NULL if so.
2259 : : */
2260 : 2220259 : lock = locallock->lock;
2261 [ + + ]: 2220259 : if (!lock)
2262 : : {
2263 : : PROCLOCKTAG proclocktag;
2264 : :
2265 : : Assert(EligibleForRelationFastPath(locktag, lockmode));
2266 : 7 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
2267 : : locktag,
2268 : : locallock->hashcode,
2269 : : HASH_FIND,
2270 : : NULL);
2271 [ - + ]: 7 : if (!lock)
2272 [ # # ]: 0 : elog(ERROR, "failed to re-find shared lock object");
2273 : 7 : locallock->lock = lock;
2274 : :
2275 : 7 : proclocktag.myLock = lock;
2276 : 7 : proclocktag.myProc = MyProc;
2277 : 7 : locallock->proclock = (PROCLOCK *) hash_search(LockMethodProcLockHash,
2278 : : &proclocktag,
2279 : : HASH_FIND,
2280 : : NULL);
2281 [ - + ]: 7 : if (!locallock->proclock)
2282 [ # # ]: 0 : elog(ERROR, "failed to re-find shared proclock object");
2283 : : }
2284 : : LOCK_PRINT("LockRelease: found", lock, lockmode);
2285 : 2220259 : proclock = locallock->proclock;
2286 : : PROCLOCK_PRINT("LockRelease: found", proclock);
2287 : :
2288 : : /*
2289 : : * Double-check that we are actually holding a lock of the type we want to
2290 : : * release.
2291 : : */
2292 [ - + ]: 2220259 : if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
2293 : : {
2294 : : PROCLOCK_PRINT("LockRelease: WRONGTYPE", proclock);
2295 : 0 : LWLockRelease(partitionLock);
2296 [ # # ]: 0 : elog(WARNING, "you don't own a lock of type %s",
2297 : : lockMethodTable->lockModeNames[lockmode]);
2298 : 0 : RemoveLocalLock(locallock);
2299 : 0 : return false;
2300 : : }
2301 : :
2302 : : /*
2303 : : * Do the releasing. CleanUpLock will waken any now-wakable waiters.
2304 : : */
2305 : 2220259 : wakeupNeeded = UnGrantLock(lock, lockmode, proclock, lockMethodTable);
2306 : :
2307 : 2220259 : CleanUpLock(lock, proclock,
2308 : : lockMethodTable, locallock->hashcode,
2309 : : wakeupNeeded);
2310 : :
2311 : 2220259 : LWLockRelease(partitionLock);
2312 : :
2313 : 2220259 : RemoveLocalLock(locallock);
2314 : 2220259 : return true;
2315 : : }
2316 : :
2317 : : /*
2318 : : * LockReleaseAll -- Release all locks of the specified lock method that
2319 : : * are held by the current process.
2320 : : *
2321 : : * Well, not necessarily *all* locks. The available behaviors are:
2322 : : * allLocks == true: release all locks including session locks.
2323 : : * allLocks == false: release all non-session locks.
2324 : : */
2325 : : void
2326 : 1362544 : LockReleaseAll(LOCKMETHODID lockmethodid, bool allLocks)
2327 : : {
2328 : : HASH_SEQ_STATUS status;
2329 : : LockMethod lockMethodTable;
2330 : : int i,
2331 : : numLockModes;
2332 : : LOCALLOCK *locallock;
2333 : : LOCK *lock;
2334 : : int partition;
2335 : 1362544 : bool have_fast_path_lwlock = false;
2336 : :
2337 [ + - - + ]: 1362544 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2338 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2339 : 1362544 : lockMethodTable = LockMethods[lockmethodid];
2340 : :
2341 : : #ifdef LOCK_DEBUG
2342 : : if (*(lockMethodTable->trace_flag))
2343 : : elog(LOG, "LockReleaseAll: lockmethod=%d", lockmethodid);
2344 : : #endif
2345 : :
2346 : : /*
2347 : : * Get rid of our fast-path VXID lock, if appropriate. Note that this is
2348 : : * the only way that the lock we hold on our own VXID can ever get
2349 : : * released: it is always and only released when a toplevel transaction
2350 : : * ends.
2351 : : */
2352 [ + + ]: 1362544 : if (lockmethodid == DEFAULT_LOCKMETHOD)
2353 : 671169 : VirtualXactLockTableCleanup();
2354 : :
2355 : 1362544 : numLockModes = lockMethodTable->numLockModes;
2356 : :
2357 : : /*
2358 : : * First we run through the locallock table and get rid of unwanted
2359 : : * entries, then we scan the process's proclocks and get rid of those. We
2360 : : * do this separately because we may have multiple locallock entries
2361 : : * pointing to the same proclock, and we daren't end up with any dangling
2362 : : * pointers. Fast-path locks are cleaned up during the locallock table
2363 : : * scan, though.
2364 : : */
2365 : 1362544 : hash_seq_init(&status, LockMethodLocalHash);
2366 : :
2367 [ + + ]: 3299717 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2368 : : {
2369 : : /*
2370 : : * If the LOCALLOCK entry is unused, something must've gone wrong
2371 : : * while trying to acquire this lock. Just forget the local entry.
2372 : : */
2373 [ + + ]: 1937173 : if (locallock->nLocks == 0)
2374 : : {
2375 : 48 : RemoveLocalLock(locallock);
2376 : 48 : continue;
2377 : : }
2378 : :
2379 : : /* Ignore items that are not of the lockmethod to be removed */
2380 [ + + ]: 1937125 : if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
2381 : 149780 : continue;
2382 : :
2383 : : /*
2384 : : * If we are asked to release all locks, we can just zap the entry.
2385 : : * Otherwise, must scan to see if there are session locks. We assume
2386 : : * there is at most one lockOwners entry for session locks.
2387 : : */
2388 [ + + ]: 1787345 : if (!allLocks)
2389 : : {
2390 : 1679847 : LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
2391 : :
2392 : : /* If session lock is above array position 0, move it down to 0 */
2393 [ + + ]: 3495716 : for (i = 0; i < locallock->numLockOwners; i++)
2394 : : {
2395 [ + + ]: 1815869 : if (lockOwners[i].owner == NULL)
2396 : 149461 : lockOwners[0] = lockOwners[i];
2397 : : else
2398 : 1666408 : ResourceOwnerForgetLock(lockOwners[i].owner, locallock);
2399 : : }
2400 : :
2401 [ + - ]: 1679847 : if (locallock->numLockOwners > 0 &&
2402 [ + + ]: 1679847 : lockOwners[0].owner == NULL &&
2403 [ + - ]: 149461 : lockOwners[0].nLocks > 0)
2404 : : {
2405 : : /* Fix the locallock to show just the session locks */
2406 : 149461 : locallock->nLocks = lockOwners[0].nLocks;
2407 : 149461 : locallock->numLockOwners = 1;
2408 : : /* We aren't deleting this locallock, so done */
2409 : 149461 : continue;
2410 : : }
2411 : : else
2412 : 1530386 : locallock->numLockOwners = 0;
2413 : : }
2414 : :
2415 : : #ifdef USE_ASSERT_CHECKING
2416 : :
2417 : : /*
2418 : : * Tuple locks are currently held only for short durations within a
2419 : : * transaction. Check that we didn't forget to release one.
2420 : : */
2421 : : if (LOCALLOCK_LOCKTAG(*locallock) == LOCKTAG_TUPLE && !allLocks)
2422 : : elog(WARNING, "tuple lock held at commit");
2423 : : #endif
2424 : :
2425 : : /*
2426 : : * If the lock or proclock pointers are NULL, this lock was taken via
2427 : : * the relation fast-path (and is not known to have been transferred).
2428 : : */
2429 [ + + - + ]: 1637884 : if (locallock->proclock == NULL || locallock->lock == NULL)
2430 : 1601 : {
2431 : 837232 : LOCKMODE lockmode = locallock->tag.mode;
2432 : : Oid relid;
2433 : :
2434 : : /* Verify that a fast-path lock is what we've got. */
2435 [ + - + - : 837232 : if (!EligibleForRelationFastPath(&locallock->tag.lock, lockmode))
+ - + - -
+ ]
2436 [ # # ]: 0 : elog(PANIC, "locallock table corrupted");
2437 : :
2438 : : /*
2439 : : * If we don't currently hold the LWLock that protects our
2440 : : * fast-path data structures, we must acquire it before attempting
2441 : : * to release the lock via the fast-path. We will continue to
2442 : : * hold the LWLock until we're done scanning the locallock table,
2443 : : * unless we hit a transferred fast-path lock. (XXX is this
2444 : : * really such a good idea? There could be a lot of entries ...)
2445 : : */
2446 [ + + ]: 837232 : if (!have_fast_path_lwlock)
2447 : : {
2448 : 291759 : LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
2449 : 291759 : have_fast_path_lwlock = true;
2450 : : }
2451 : :
2452 : : /* Attempt fast-path release. */
2453 : 837232 : relid = locallock->tag.lock.locktag_field2;
2454 [ + + ]: 837232 : if (FastPathUnGrantRelationLock(relid, lockmode))
2455 : : {
2456 : 835631 : RemoveLocalLock(locallock);
2457 : 835631 : continue;
2458 : : }
2459 : :
2460 : : /*
2461 : : * Our lock, originally taken via the fast path, has been
2462 : : * transferred to the main lock table. That's going to require
2463 : : * some extra work, so release our fast-path lock before starting.
2464 : : */
2465 : 1601 : LWLockRelease(&MyProc->fpInfoLock);
2466 : 1601 : have_fast_path_lwlock = false;
2467 : :
2468 : : /*
2469 : : * Now dump the lock. We haven't got a pointer to the LOCK or
2470 : : * PROCLOCK in this case, so we have to handle this a bit
2471 : : * differently than a normal lock release. Unfortunately, this
2472 : : * requires an extra LWLock acquire-and-release cycle on the
2473 : : * partitionLock, but hopefully it shouldn't happen often.
2474 : : */
2475 : 1601 : LockRefindAndRelease(lockMethodTable, MyProc,
2476 : : &locallock->tag.lock, lockmode, false);
2477 : 1601 : RemoveLocalLock(locallock);
2478 : 1601 : continue;
2479 : : }
2480 : :
2481 : : /* Mark the proclock to show we need to release this lockmode */
2482 [ + - ]: 800652 : if (locallock->nLocks > 0)
2483 : 800652 : locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
2484 : :
2485 : : /* And remove the locallock hashtable entry */
2486 : 800652 : RemoveLocalLock(locallock);
2487 : : }
2488 : :
2489 : : /* Done with the fast-path data structures */
2490 [ + + ]: 1362544 : if (have_fast_path_lwlock)
2491 : 290158 : LWLockRelease(&MyProc->fpInfoLock);
2492 : :
2493 : : /*
2494 : : * Now, scan each lock partition separately.
2495 : : */
2496 [ + + ]: 23163248 : for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
2497 : : {
2498 : : LWLock *partitionLock;
2499 : 21800704 : dlist_head *procLocks = &MyProc->myProcLocks[partition];
2500 : : dlist_mutable_iter proclock_iter;
2501 : :
2502 : 21800704 : partitionLock = LockHashPartitionLockByIndex(partition);
2503 : :
2504 : : /*
2505 : : * If the proclock list for this partition is empty, we can skip
2506 : : * acquiring the partition lock. This optimization is trickier than
2507 : : * it looks, because another backend could be in process of adding
2508 : : * something to our proclock list due to promoting one of our
2509 : : * fast-path locks. However, any such lock must be one that we
2510 : : * decided not to delete above, so it's okay to skip it again now;
2511 : : * we'd just decide not to delete it again. We must, however, be
2512 : : * careful to re-fetch the list header once we've acquired the
2513 : : * partition lock, to be sure we have a valid, up-to-date pointer.
2514 : : * (There is probably no significant risk if pointer fetch/store is
2515 : : * atomic, but we don't wish to assume that.)
2516 : : *
2517 : : * XXX This argument assumes that the locallock table correctly
2518 : : * represents all of our fast-path locks. While allLocks mode
2519 : : * guarantees to clean up all of our normal locks regardless of the
2520 : : * locallock situation, we lose that guarantee for fast-path locks.
2521 : : * This is not ideal.
2522 : : */
2523 [ + + ]: 21800704 : if (dlist_is_empty(procLocks))
2524 : 20916151 : continue; /* needn't examine this partition */
2525 : :
2526 : 884553 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2527 : :
2528 [ + - + + ]: 1935153 : dlist_foreach_modify(proclock_iter, procLocks)
2529 : : {
2530 : 1050600 : PROCLOCK *proclock = dlist_container(PROCLOCK, procLink, proclock_iter.cur);
2531 : 1050600 : bool wakeupNeeded = false;
2532 : :
2533 : : Assert(proclock->tag.myProc == MyProc);
2534 : :
2535 : 1050600 : lock = proclock->tag.myLock;
2536 : :
2537 : : /* Ignore items that are not of the lockmethod to be removed */
2538 [ + + ]: 1050600 : if (LOCK_LOCKMETHOD(*lock) != lockmethodid)
2539 : 149779 : continue;
2540 : :
2541 : : /*
2542 : : * In allLocks mode, force release of all locks even if locallock
2543 : : * table had problems
2544 : : */
2545 [ + + ]: 900821 : if (allLocks)
2546 : 46666 : proclock->releaseMask = proclock->holdMask;
2547 : : else
2548 : : Assert((proclock->releaseMask & ~proclock->holdMask) == 0);
2549 : :
2550 : : /*
2551 : : * Ignore items that have nothing to be released, unless they have
2552 : : * holdMask == 0 and are therefore recyclable
2553 : : */
2554 [ + + + - ]: 900821 : if (proclock->releaseMask == 0 && proclock->holdMask != 0)
2555 : 148547 : continue;
2556 : :
2557 : : PROCLOCK_PRINT("LockReleaseAll", proclock);
2558 : : LOCK_PRINT("LockReleaseAll", lock, 0);
2559 : : Assert(lock->nRequested >= 0);
2560 : : Assert(lock->nGranted >= 0);
2561 : : Assert(lock->nGranted <= lock->nRequested);
2562 : : Assert((proclock->holdMask & ~lock->grantMask) == 0);
2563 : :
2564 : : /*
2565 : : * Release the previously-marked lock modes
2566 : : */
2567 [ + + ]: 6770466 : for (i = 1; i <= numLockModes; i++)
2568 : : {
2569 [ + + ]: 6018192 : if (proclock->releaseMask & LOCKBIT_ON(i))
2570 : 800653 : wakeupNeeded |= UnGrantLock(lock, i, proclock,
2571 : : lockMethodTable);
2572 : : }
2573 : : Assert((lock->nRequested >= 0) && (lock->nGranted >= 0));
2574 : : Assert(lock->nGranted <= lock->nRequested);
2575 : : LOCK_PRINT("LockReleaseAll: updated", lock, 0);
2576 : :
2577 : 752274 : proclock->releaseMask = 0;
2578 : :
2579 : : /* CleanUpLock will wake up waiters if needed. */
2580 : 752274 : CleanUpLock(lock, proclock,
2581 : : lockMethodTable,
2582 : 752274 : LockTagHashCode(&lock->tag),
2583 : : wakeupNeeded);
2584 : : } /* loop over PROCLOCKs within this partition */
2585 : :
2586 : 884553 : LWLockRelease(partitionLock);
2587 : : } /* loop over partitions */
2588 : :
2589 : : #ifdef LOCK_DEBUG
2590 : : if (*(lockMethodTable->trace_flag))
2591 : : elog(LOG, "LockReleaseAll done");
2592 : : #endif
2593 : 1362544 : }
2594 : :
2595 : : /*
2596 : : * LockReleaseSession -- Release all session locks of the specified lock method
2597 : : * that are held by the current process.
2598 : : */
2599 : : void
2600 : 122 : LockReleaseSession(LOCKMETHODID lockmethodid)
2601 : : {
2602 : : HASH_SEQ_STATUS status;
2603 : : LOCALLOCK *locallock;
2604 : :
2605 [ + - - + ]: 122 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
2606 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
2607 : :
2608 : 122 : hash_seq_init(&status, LockMethodLocalHash);
2609 : :
2610 [ + + ]: 242 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2611 : : {
2612 : : /* Ignore items that are not of the specified lock method */
2613 [ + + ]: 120 : if (LOCALLOCK_LOCKMETHOD(*locallock) != lockmethodid)
2614 : 11 : continue;
2615 : :
2616 : 109 : ReleaseLockIfHeld(locallock, true);
2617 : : }
2618 : 122 : }
2619 : :
2620 : : /*
2621 : : * LockReleaseCurrentOwner
2622 : : * Release all locks belonging to CurrentResourceOwner
2623 : : *
2624 : : * If the caller knows what those locks are, it can pass them as an array.
2625 : : * That speeds up the call significantly, when a lot of locks are held.
2626 : : * Otherwise, pass NULL for locallocks, and we'll traverse through our hash
2627 : : * table to find them.
2628 : : */
2629 : : void
2630 : 6332 : LockReleaseCurrentOwner(LOCALLOCK **locallocks, int nlocks)
2631 : : {
2632 [ + + ]: 6332 : if (locallocks == NULL)
2633 : : {
2634 : : HASH_SEQ_STATUS status;
2635 : : LOCALLOCK *locallock;
2636 : :
2637 : 9 : hash_seq_init(&status, LockMethodLocalHash);
2638 : :
2639 [ + + ]: 647 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2640 : 638 : ReleaseLockIfHeld(locallock, false);
2641 : : }
2642 : : else
2643 : : {
2644 : : int i;
2645 : :
2646 [ + + ]: 9815 : for (i = nlocks - 1; i >= 0; i--)
2647 : 3492 : ReleaseLockIfHeld(locallocks[i], false);
2648 : : }
2649 : 6332 : }
2650 : :
2651 : : /*
2652 : : * ReleaseLockIfHeld
2653 : : * Release any session-level locks on this lockable object if sessionLock
2654 : : * is true; else, release any locks held by CurrentResourceOwner.
2655 : : *
2656 : : * It is tempting to pass this a ResourceOwner pointer (or NULL for session
2657 : : * locks), but without refactoring LockRelease() we cannot support releasing
2658 : : * locks belonging to resource owners other than CurrentResourceOwner.
2659 : : * If we were to refactor, it'd be a good idea to fix it so we don't have to
2660 : : * do a hashtable lookup of the locallock, too. However, currently this
2661 : : * function isn't used heavily enough to justify refactoring for its
2662 : : * convenience.
2663 : : */
2664 : : static void
2665 : 4239 : ReleaseLockIfHeld(LOCALLOCK *locallock, bool sessionLock)
2666 : : {
2667 : : ResourceOwner owner;
2668 : : LOCALLOCKOWNER *lockOwners;
2669 : : int i;
2670 : :
2671 : : /* Identify owner for lock (must match LockRelease!) */
2672 [ + + ]: 4239 : if (sessionLock)
2673 : 109 : owner = NULL;
2674 : : else
2675 : 4130 : owner = CurrentResourceOwner;
2676 : :
2677 : : /* Scan to see if there are any locks belonging to the target owner */
2678 : 4239 : lockOwners = locallock->lockOwners;
2679 [ + + ]: 4708 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
2680 : : {
2681 [ + + ]: 4239 : if (lockOwners[i].owner == owner)
2682 : : {
2683 : : Assert(lockOwners[i].nLocks > 0);
2684 [ + + ]: 3770 : if (lockOwners[i].nLocks < locallock->nLocks)
2685 : : {
2686 : : /*
2687 : : * We will still hold this lock after forgetting this
2688 : : * ResourceOwner.
2689 : : */
2690 : 977 : locallock->nLocks -= lockOwners[i].nLocks;
2691 : : /* compact out unused slot */
2692 : 977 : locallock->numLockOwners--;
2693 [ + - ]: 977 : if (owner != NULL)
2694 : 977 : ResourceOwnerForgetLock(owner, locallock);
2695 [ - + ]: 977 : if (i < locallock->numLockOwners)
2696 : 0 : lockOwners[i] = lockOwners[locallock->numLockOwners];
2697 : : }
2698 : : else
2699 : : {
2700 : : Assert(lockOwners[i].nLocks == locallock->nLocks);
2701 : : /* We want to call LockRelease just once */
2702 : 2793 : lockOwners[i].nLocks = 1;
2703 : 2793 : locallock->nLocks = 1;
2704 [ - + ]: 2793 : if (!LockRelease(&locallock->tag.lock,
2705 : : locallock->tag.mode,
2706 : : sessionLock))
2707 [ # # ]: 0 : elog(WARNING, "ReleaseLockIfHeld: failed??");
2708 : : }
2709 : 3770 : break;
2710 : : }
2711 : : }
2712 : 4239 : }
2713 : :
2714 : : /*
2715 : : * LockReassignCurrentOwner
2716 : : * Reassign all locks belonging to CurrentResourceOwner to belong
2717 : : * to its parent resource owner.
2718 : : *
2719 : : * If the caller knows what those locks are, it can pass them as an array.
2720 : : * That speeds up the call significantly, when a lot of locks are held
2721 : : * (e.g pg_dump with a large schema). Otherwise, pass NULL for locallocks,
2722 : : * and we'll traverse through our hash table to find them.
2723 : : */
2724 : : void
2725 : 449240 : LockReassignCurrentOwner(LOCALLOCK **locallocks, int nlocks)
2726 : : {
2727 : 449240 : ResourceOwner parent = ResourceOwnerGetParent(CurrentResourceOwner);
2728 : :
2729 : : Assert(parent != NULL);
2730 : :
2731 [ + + ]: 449240 : if (locallocks == NULL)
2732 : : {
2733 : : HASH_SEQ_STATUS status;
2734 : : LOCALLOCK *locallock;
2735 : :
2736 : 8033 : hash_seq_init(&status, LockMethodLocalHash);
2737 : :
2738 [ + + ]: 241461 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
2739 : 233428 : LockReassignOwner(locallock, parent);
2740 : : }
2741 : : else
2742 : : {
2743 : : int i;
2744 : :
2745 [ + + ]: 1021325 : for (i = nlocks - 1; i >= 0; i--)
2746 : 580118 : LockReassignOwner(locallocks[i], parent);
2747 : : }
2748 : 449240 : }
2749 : :
2750 : : /*
2751 : : * Subroutine of LockReassignCurrentOwner. Reassigns a given lock belonging to
2752 : : * CurrentResourceOwner to its parent.
2753 : : */
2754 : : static void
2755 : 813546 : LockReassignOwner(LOCALLOCK *locallock, ResourceOwner parent)
2756 : : {
2757 : : LOCALLOCKOWNER *lockOwners;
2758 : : int i;
2759 : 813546 : int ic = -1;
2760 : 813546 : int ip = -1;
2761 : :
2762 : : /*
2763 : : * Scan to see if there are any locks belonging to current owner or its
2764 : : * parent
2765 : : */
2766 : 813546 : lockOwners = locallock->lockOwners;
2767 [ + + ]: 1825452 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
2768 : : {
2769 [ + + ]: 1011906 : if (lockOwners[i].owner == CurrentResourceOwner)
2770 : 752780 : ic = i;
2771 [ + + ]: 259126 : else if (lockOwners[i].owner == parent)
2772 : 215148 : ip = i;
2773 : : }
2774 : :
2775 [ + + ]: 813546 : if (ic < 0)
2776 : 60766 : return; /* no current locks */
2777 : :
2778 [ + + ]: 752780 : if (ip < 0)
2779 : : {
2780 : : /* Parent has no slot, so just give it the child's slot */
2781 : 598362 : lockOwners[ic].owner = parent;
2782 : 598362 : ResourceOwnerRememberLock(parent, locallock);
2783 : : }
2784 : : else
2785 : : {
2786 : : /* Merge child's count with parent's */
2787 : 154418 : lockOwners[ip].nLocks += lockOwners[ic].nLocks;
2788 : : /* compact out unused slot */
2789 : 154418 : locallock->numLockOwners--;
2790 [ + + ]: 154418 : if (ic < locallock->numLockOwners)
2791 : 914 : lockOwners[ic] = lockOwners[locallock->numLockOwners];
2792 : : }
2793 : 752780 : ResourceOwnerForgetLock(CurrentResourceOwner, locallock);
2794 : : }
2795 : :
2796 : : /*
2797 : : * FastPathGrantRelationLock
2798 : : * Grant lock using per-backend fast-path array, if there is space.
2799 : : */
2800 : : static bool
2801 : 21828549 : FastPathGrantRelationLock(Oid relid, LOCKMODE lockmode)
2802 : : {
2803 : : uint32 i;
2804 : 21828549 : uint32 unused_slot = FastPathLockSlotsPerBackend();
2805 : :
2806 : : /* fast-path group the lock belongs to */
2807 : 21828549 : uint32 group = FAST_PATH_REL_GROUP(relid);
2808 : :
2809 : : /* Scan for existing entry for this relid, remembering empty slot. */
2810 [ + + ]: 370293578 : for (i = 0; i < FP_LOCK_SLOTS_PER_GROUP; i++)
2811 : : {
2812 : : /* index into the whole per-backend array */
2813 : 349119961 : uint32 f = FAST_PATH_SLOT(group, i);
2814 : :
2815 [ + + ]: 349119961 : if (FAST_PATH_GET_BITS(MyProc, f) == 0)
2816 : 341803330 : unused_slot = f;
2817 [ + + ]: 7316631 : else if (MyProc->fpRelId[f] == relid)
2818 : : {
2819 : : Assert(!FAST_PATH_CHECK_LOCKMODE(MyProc, f, lockmode));
2820 : 654932 : FAST_PATH_SET_LOCKMODE(MyProc, f, lockmode);
2821 : 654932 : return true;
2822 : : }
2823 : : }
2824 : :
2825 : : /* If no existing entry, use any empty slot. */
2826 [ + - ]: 21173617 : if (unused_slot < FastPathLockSlotsPerBackend())
2827 : : {
2828 : 21173617 : MyProc->fpRelId[unused_slot] = relid;
2829 : 21173617 : FAST_PATH_SET_LOCKMODE(MyProc, unused_slot, lockmode);
2830 : 21173617 : ++FastPathLocalUseCounts[group];
2831 : 21173617 : return true;
2832 : : }
2833 : :
2834 : : /* No existing entry, and no empty slot. */
2835 : 0 : return false;
2836 : : }
2837 : :
2838 : : /*
2839 : : * FastPathUnGrantRelationLock
2840 : : * Release fast-path lock, if present. Update backend-private local
2841 : : * use count, while we're at it.
2842 : : */
2843 : : static bool
2844 : 21947102 : FastPathUnGrantRelationLock(Oid relid, LOCKMODE lockmode)
2845 : : {
2846 : : uint32 i;
2847 : 21947102 : bool result = false;
2848 : :
2849 : : /* fast-path group the lock belongs to */
2850 : 21947102 : uint32 group = FAST_PATH_REL_GROUP(relid);
2851 : :
2852 : 21947102 : FastPathLocalUseCounts[group] = 0;
2853 [ + + ]: 373100734 : for (i = 0; i < FP_LOCK_SLOTS_PER_GROUP; i++)
2854 : : {
2855 : : /* index into the whole per-backend array */
2856 : 351153632 : uint32 f = FAST_PATH_SLOT(group, i);
2857 : :
2858 [ + + ]: 351153632 : if (MyProc->fpRelId[f] == relid
2859 [ + + ]: 32702847 : && FAST_PATH_CHECK_LOCKMODE(MyProc, f, lockmode))
2860 : : {
2861 : : Assert(!result);
2862 : 21826593 : FAST_PATH_CLEAR_LOCKMODE(MyProc, f, lockmode);
2863 : 21826593 : result = true;
2864 : : /* we continue iterating so as to update FastPathLocalUseCount */
2865 : : }
2866 [ + + ]: 351153632 : if (FAST_PATH_GET_BITS(MyProc, f) != 0)
2867 : 8893542 : ++FastPathLocalUseCounts[group];
2868 : : }
2869 : 21947102 : return result;
2870 : : }
2871 : :
2872 : : /*
2873 : : * FastPathTransferRelationLocks
2874 : : * Transfer locks matching the given lock tag from per-backend fast-path
2875 : : * arrays to the shared hash table.
2876 : : *
2877 : : * Returns true if successful, false if ran out of shared memory.
2878 : : */
2879 : : static bool
2880 : 251906 : FastPathTransferRelationLocks(LockMethod lockMethodTable, const LOCKTAG *locktag,
2881 : : uint32 hashcode)
2882 : : {
2883 : 251906 : LWLock *partitionLock = LockHashPartitionLock(hashcode);
2884 : 251906 : Oid relid = locktag->locktag_field2;
2885 : : uint32 i;
2886 : :
2887 : : /* fast-path group the lock belongs to */
2888 : 251906 : uint32 group = FAST_PATH_REL_GROUP(relid);
2889 : :
2890 : : /*
2891 : : * Every PGPROC that can potentially hold a fast-path lock is present in
2892 : : * ProcGlobal->allProcs. Prepared transactions are not, but any
2893 : : * outstanding fast-path locks held by prepared transactions are
2894 : : * transferred to the main lock table.
2895 : : */
2896 [ + + ]: 37474903 : for (i = 0; i < ProcGlobal->allProcCount; i++)
2897 : : {
2898 : 37222997 : PGPROC *proc = GetPGProcByNumber(i);
2899 : : uint32 j;
2900 : :
2901 : 37222997 : LWLockAcquire(&proc->fpInfoLock, LW_EXCLUSIVE);
2902 : :
2903 : : /*
2904 : : * If the target backend isn't referencing the same database as the
2905 : : * lock, then we needn't examine the individual relation IDs at all;
2906 : : * none of them can be relevant.
2907 : : *
2908 : : * proc->databaseId is set at backend startup time and never changes
2909 : : * thereafter, so it might be safe to perform this test before
2910 : : * acquiring &proc->fpInfoLock. In particular, it's certainly safe to
2911 : : * assume that if the target backend holds any fast-path locks, it
2912 : : * must have performed a memory-fencing operation (in particular, an
2913 : : * LWLock acquisition) since setting proc->databaseId. However, it's
2914 : : * less clear that our backend is certain to have performed a memory
2915 : : * fencing operation since the other backend set proc->databaseId. So
2916 : : * for now, we test it after acquiring the LWLock just to be safe.
2917 : : *
2918 : : * Also skip groups without any registered fast-path locks.
2919 : : */
2920 [ + + ]: 37222997 : if (proc->databaseId != locktag->locktag_field1 ||
2921 [ + + ]: 14687443 : proc->fpLockBits[group] == 0)
2922 : : {
2923 : 37077528 : LWLockRelease(&proc->fpInfoLock);
2924 : 37077528 : continue;
2925 : : }
2926 : :
2927 [ + + ]: 2471298 : for (j = 0; j < FP_LOCK_SLOTS_PER_GROUP; j++)
2928 : : {
2929 : : uint32 lockmode;
2930 : :
2931 : : /* index into the whole per-backend array */
2932 : 2327387 : uint32 f = FAST_PATH_SLOT(group, j);
2933 : :
2934 : : /* Look for an allocated slot matching the given relid. */
2935 [ + + + + ]: 2327387 : if (relid != proc->fpRelId[f] || FAST_PATH_GET_BITS(proc, f) == 0)
2936 : 2325829 : continue;
2937 : :
2938 : : /* Find or create lock object. */
2939 : 1558 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
2940 : 1558 : for (lockmode = FAST_PATH_LOCKNUMBER_OFFSET;
2941 [ + + ]: 6232 : lockmode < FAST_PATH_LOCKNUMBER_OFFSET + FAST_PATH_BITS_PER_SLOT;
2942 : 4674 : ++lockmode)
2943 : : {
2944 : : PROCLOCK *proclock;
2945 : :
2946 [ + + ]: 4674 : if (!FAST_PATH_CHECK_LOCKMODE(proc, f, lockmode))
2947 : 3050 : continue;
2948 : 1624 : proclock = SetupLockInTable(lockMethodTable, proc, locktag,
2949 : : hashcode, lockmode);
2950 [ - + ]: 1624 : if (!proclock)
2951 : : {
2952 : 0 : LWLockRelease(partitionLock);
2953 : 0 : LWLockRelease(&proc->fpInfoLock);
2954 : 0 : return false;
2955 : : }
2956 : 1624 : GrantLock(proclock->tag.myLock, proclock, lockmode);
2957 : 1624 : FAST_PATH_CLEAR_LOCKMODE(proc, f, lockmode);
2958 : : }
2959 : 1558 : LWLockRelease(partitionLock);
2960 : :
2961 : : /* No need to examine remaining slots. */
2962 : 1558 : break;
2963 : : }
2964 : 145469 : LWLockRelease(&proc->fpInfoLock);
2965 : : }
2966 : 251906 : return true;
2967 : : }
2968 : :
2969 : : /*
2970 : : * FastPathGetRelationLockEntry
2971 : : * Return the PROCLOCK for a lock originally taken via the fast-path,
2972 : : * transferring it to the primary lock table if necessary.
2973 : : *
2974 : : * Note: caller takes care of updating the locallock object.
2975 : : */
2976 : : static PROCLOCK *
2977 : 348 : FastPathGetRelationLockEntry(LOCALLOCK *locallock)
2978 : : {
2979 : 348 : LockMethod lockMethodTable = LockMethods[DEFAULT_LOCKMETHOD];
2980 : 348 : LOCKTAG *locktag = &locallock->tag.lock;
2981 : 348 : PROCLOCK *proclock = NULL;
2982 : 348 : LWLock *partitionLock = LockHashPartitionLock(locallock->hashcode);
2983 : 348 : Oid relid = locktag->locktag_field2;
2984 : : uint32 i,
2985 : : group;
2986 : :
2987 : : /* fast-path group the lock belongs to */
2988 : 348 : group = FAST_PATH_REL_GROUP(relid);
2989 : :
2990 : 348 : LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
2991 : :
2992 [ + + ]: 5578 : for (i = 0; i < FP_LOCK_SLOTS_PER_GROUP; i++)
2993 : : {
2994 : : uint32 lockmode;
2995 : :
2996 : : /* index into the whole per-backend array */
2997 : 5562 : uint32 f = FAST_PATH_SLOT(group, i);
2998 : :
2999 : : /* Look for an allocated slot matching the given relid. */
3000 [ + + - + ]: 5562 : if (relid != MyProc->fpRelId[f] || FAST_PATH_GET_BITS(MyProc, f) == 0)
3001 : 5230 : continue;
3002 : :
3003 : : /* If we don't have a lock of the given mode, forget it! */
3004 : 332 : lockmode = locallock->tag.mode;
3005 [ - + ]: 332 : if (!FAST_PATH_CHECK_LOCKMODE(MyProc, f, lockmode))
3006 : 0 : break;
3007 : :
3008 : : /* Find or create lock object. */
3009 : 332 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
3010 : :
3011 : 332 : proclock = SetupLockInTable(lockMethodTable, MyProc, locktag,
3012 : : locallock->hashcode, lockmode);
3013 [ - + ]: 332 : if (!proclock)
3014 : : {
3015 : 0 : LWLockRelease(partitionLock);
3016 : 0 : LWLockRelease(&MyProc->fpInfoLock);
3017 [ # # ]: 0 : ereport(ERROR,
3018 : : (errcode(ERRCODE_OUT_OF_MEMORY),
3019 : : errmsg("out of shared memory"),
3020 : : errhint("You might need to increase \"%s\".", "max_locks_per_transaction")));
3021 : : }
3022 : 332 : GrantLock(proclock->tag.myLock, proclock, lockmode);
3023 : 332 : FAST_PATH_CLEAR_LOCKMODE(MyProc, f, lockmode);
3024 : :
3025 : 332 : LWLockRelease(partitionLock);
3026 : :
3027 : : /* No need to examine remaining slots. */
3028 : 332 : break;
3029 : : }
3030 : :
3031 : 348 : LWLockRelease(&MyProc->fpInfoLock);
3032 : :
3033 : : /* Lock may have already been transferred by some other backend. */
3034 [ + + ]: 348 : if (proclock == NULL)
3035 : : {
3036 : : LOCK *lock;
3037 : : PROCLOCKTAG proclocktag;
3038 : : uint32 proclock_hashcode;
3039 : :
3040 : 16 : LWLockAcquire(partitionLock, LW_SHARED);
3041 : :
3042 : 16 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
3043 : : locktag,
3044 : : locallock->hashcode,
3045 : : HASH_FIND,
3046 : : NULL);
3047 [ - + ]: 16 : if (!lock)
3048 [ # # ]: 0 : elog(ERROR, "failed to re-find shared lock object");
3049 : :
3050 : 16 : proclocktag.myLock = lock;
3051 : 16 : proclocktag.myProc = MyProc;
3052 : :
3053 : 16 : proclock_hashcode = ProcLockHashCode(&proclocktag, locallock->hashcode);
3054 : : proclock = (PROCLOCK *)
3055 : 16 : hash_search_with_hash_value(LockMethodProcLockHash,
3056 : : &proclocktag,
3057 : : proclock_hashcode,
3058 : : HASH_FIND,
3059 : : NULL);
3060 [ - + ]: 16 : if (!proclock)
3061 [ # # ]: 0 : elog(ERROR, "failed to re-find shared proclock object");
3062 : 16 : LWLockRelease(partitionLock);
3063 : : }
3064 : :
3065 : 348 : return proclock;
3066 : : }
3067 : :
3068 : : /*
3069 : : * GetLockConflicts
3070 : : * Get an array of VirtualTransactionIds of xacts currently holding locks
3071 : : * that would conflict with the specified lock/lockmode.
3072 : : * xacts merely awaiting such a lock are NOT reported.
3073 : : *
3074 : : * The result array is palloc'd and is terminated with an invalid VXID.
3075 : : * *countp, if not null, is updated to the number of items set.
3076 : : *
3077 : : * Of course, the result could be out of date by the time it's returned, so
3078 : : * use of this function has to be thought about carefully. Similarly, a
3079 : : * PGPROC with no "lxid" will be considered non-conflicting regardless of any
3080 : : * lock it holds. Existing callers don't care about a locker after that
3081 : : * locker's pg_xact updates complete. CommitTransaction() clears "lxid" after
3082 : : * pg_xact updates and before releasing locks.
3083 : : *
3084 : : * Note we never include the current xact's vxid in the result array,
3085 : : * since an xact never blocks itself.
3086 : : */
3087 : : VirtualTransactionId *
3088 : 1838 : GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode, int *countp)
3089 : : {
3090 : : static VirtualTransactionId *vxids;
3091 : 1838 : LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
3092 : : LockMethod lockMethodTable;
3093 : : LOCK *lock;
3094 : : LOCKMASK conflictMask;
3095 : : dlist_iter proclock_iter;
3096 : : PROCLOCK *proclock;
3097 : : uint32 hashcode;
3098 : : LWLock *partitionLock;
3099 : 1838 : int count = 0;
3100 : 1838 : int fast_count = 0;
3101 : :
3102 [ + - - + ]: 1838 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
3103 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
3104 : 1838 : lockMethodTable = LockMethods[lockmethodid];
3105 [ + - - + ]: 1838 : if (lockmode <= 0 || lockmode > lockMethodTable->numLockModes)
3106 [ # # ]: 0 : elog(ERROR, "unrecognized lock mode: %d", lockmode);
3107 : :
3108 : : /*
3109 : : * Allocate memory to store results, and fill with InvalidVXID. We only
3110 : : * need enough space for MaxBackends + max_prepared_xacts + a terminator.
3111 : : * InHotStandby allocate once in TopMemoryContext.
3112 : : */
3113 [ + + ]: 1838 : if (InHotStandby)
3114 : : {
3115 [ + + ]: 4 : if (vxids == NULL)
3116 : 1 : vxids = (VirtualTransactionId *)
3117 : 1 : MemoryContextAlloc(TopMemoryContext,
3118 : : sizeof(VirtualTransactionId) *
3119 : 1 : (MaxBackends + max_prepared_xacts + 1));
3120 : : }
3121 : : else
3122 : 1834 : vxids = palloc0_array(VirtualTransactionId, (MaxBackends + max_prepared_xacts + 1));
3123 : :
3124 : : /* Compute hash code and partition lock, and look up conflicting modes. */
3125 : 1838 : hashcode = LockTagHashCode(locktag);
3126 : 1838 : partitionLock = LockHashPartitionLock(hashcode);
3127 : 1838 : conflictMask = lockMethodTable->conflictTab[lockmode];
3128 : :
3129 : : /*
3130 : : * Fast path locks might not have been entered in the primary lock table.
3131 : : * If the lock we're dealing with could conflict with such a lock, we must
3132 : : * examine each backend's fast-path array for conflicts.
3133 : : */
3134 [ + - + - : 1838 : if (ConflictsWithRelationFastPath(locktag, lockmode))
+ - + - ]
3135 : : {
3136 : 1838 : Oid relid = locktag->locktag_field2;
3137 : : VirtualTransactionId vxid;
3138 : :
3139 : : /* fast-path group the lock belongs to */
3140 : 1838 : uint32 group = FAST_PATH_REL_GROUP(relid);
3141 : :
3142 : : /*
3143 : : * Iterate over relevant PGPROCs. Anything held by a prepared
3144 : : * transaction will have been transferred to the primary lock table,
3145 : : * so we need not worry about those. This is all a bit fuzzy, because
3146 : : * new locks could be taken after we've visited a particular
3147 : : * partition, but the callers had better be prepared to deal with that
3148 : : * anyway, since the locks could equally well be taken between the
3149 : : * time we return the value and the time the caller does something
3150 : : * with it.
3151 : : */
3152 [ + + ]: 291062 : for (uint32 i = 0; i < ProcGlobal->allProcCount; i++)
3153 : : {
3154 : 289224 : PGPROC *proc = GetPGProcByNumber(i);
3155 : : uint32 j;
3156 : :
3157 : : /* A backend never blocks itself */
3158 [ + + ]: 289224 : if (proc == MyProc)
3159 : 1838 : continue;
3160 : :
3161 : 287386 : LWLockAcquire(&proc->fpInfoLock, LW_SHARED);
3162 : :
3163 : : /*
3164 : : * If the target backend isn't referencing the same database as
3165 : : * the lock, then we needn't examine the individual relation IDs
3166 : : * at all; none of them can be relevant.
3167 : : *
3168 : : * See FastPathTransferRelationLocks() for discussion of why we do
3169 : : * this test after acquiring the lock.
3170 : : *
3171 : : * Also skip groups without any registered fast-path locks.
3172 : : */
3173 [ + + ]: 287386 : if (proc->databaseId != locktag->locktag_field1 ||
3174 [ + + ]: 116740 : proc->fpLockBits[group] == 0)
3175 : : {
3176 : 286980 : LWLockRelease(&proc->fpInfoLock);
3177 : 286980 : continue;
3178 : : }
3179 : :
3180 [ + + ]: 6684 : for (j = 0; j < FP_LOCK_SLOTS_PER_GROUP; j++)
3181 : : {
3182 : : uint32 lockmask;
3183 : :
3184 : : /* index into the whole per-backend array */
3185 : 6496 : uint32 f = FAST_PATH_SLOT(group, j);
3186 : :
3187 : : /* Look for an allocated slot matching the given relid. */
3188 [ + + ]: 6496 : if (relid != proc->fpRelId[f])
3189 : 6278 : continue;
3190 : 218 : lockmask = FAST_PATH_GET_BITS(proc, f);
3191 [ - + ]: 218 : if (!lockmask)
3192 : 0 : continue;
3193 : 218 : lockmask <<= FAST_PATH_LOCKNUMBER_OFFSET;
3194 : :
3195 : : /*
3196 : : * There can only be one entry per relation, so if we found it
3197 : : * and it doesn't conflict, we can skip the rest of the slots.
3198 : : */
3199 [ + + ]: 218 : if ((lockmask & conflictMask) == 0)
3200 : 5 : break;
3201 : :
3202 : : /* Conflict! */
3203 : 213 : GET_VXID_FROM_PGPROC(vxid, *proc);
3204 : :
3205 [ + - ]: 213 : if (VirtualTransactionIdIsValid(vxid))
3206 : 213 : vxids[count++] = vxid;
3207 : : /* else, xact already committed or aborted */
3208 : :
3209 : : /* No need to examine remaining slots. */
3210 : 213 : break;
3211 : : }
3212 : :
3213 : 406 : LWLockRelease(&proc->fpInfoLock);
3214 : : }
3215 : : }
3216 : :
3217 : : /* Remember how many fast-path conflicts we found. */
3218 : 1838 : fast_count = count;
3219 : :
3220 : : /*
3221 : : * Look up the lock object matching the tag.
3222 : : */
3223 : 1838 : LWLockAcquire(partitionLock, LW_SHARED);
3224 : :
3225 : 1838 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
3226 : : locktag,
3227 : : hashcode,
3228 : : HASH_FIND,
3229 : : NULL);
3230 [ + + ]: 1838 : if (!lock)
3231 : : {
3232 : : /*
3233 : : * If the lock object doesn't exist, there is nothing holding a lock
3234 : : * on this lockable object.
3235 : : */
3236 : 72 : LWLockRelease(partitionLock);
3237 : 72 : vxids[count].procNumber = INVALID_PROC_NUMBER;
3238 : 72 : vxids[count].localTransactionId = InvalidLocalTransactionId;
3239 [ - + ]: 72 : if (countp)
3240 : 0 : *countp = count;
3241 : 72 : return vxids;
3242 : : }
3243 : :
3244 : : /*
3245 : : * Examine each existing holder (or awaiter) of the lock.
3246 : : */
3247 [ + - + + ]: 3547 : dlist_foreach(proclock_iter, &lock->procLocks)
3248 : : {
3249 : 1781 : proclock = dlist_container(PROCLOCK, lockLink, proclock_iter.cur);
3250 : :
3251 [ + + ]: 1781 : if (conflictMask & proclock->holdMask)
3252 : : {
3253 : 1777 : PGPROC *proc = proclock->tag.myProc;
3254 : :
3255 : : /* A backend never blocks itself */
3256 [ + + ]: 1777 : if (proc != MyProc)
3257 : : {
3258 : : VirtualTransactionId vxid;
3259 : :
3260 : 15 : GET_VXID_FROM_PGPROC(vxid, *proc);
3261 : :
3262 [ + - ]: 15 : if (VirtualTransactionIdIsValid(vxid))
3263 : : {
3264 : : int i;
3265 : :
3266 : : /* Avoid duplicate entries. */
3267 [ + + ]: 25 : for (i = 0; i < fast_count; ++i)
3268 [ - + - - ]: 10 : if (VirtualTransactionIdEquals(vxids[i], vxid))
3269 : 0 : break;
3270 [ + - ]: 15 : if (i >= fast_count)
3271 : 15 : vxids[count++] = vxid;
3272 : : }
3273 : : /* else, xact already committed or aborted */
3274 : : }
3275 : : }
3276 : : }
3277 : :
3278 : 1766 : LWLockRelease(partitionLock);
3279 : :
3280 [ - + ]: 1766 : if (count > MaxBackends + max_prepared_xacts) /* should never happen */
3281 [ # # ]: 0 : elog(PANIC, "too many conflicting locks found");
3282 : :
3283 : 1766 : vxids[count].procNumber = INVALID_PROC_NUMBER;
3284 : 1766 : vxids[count].localTransactionId = InvalidLocalTransactionId;
3285 [ + + ]: 1766 : if (countp)
3286 : 1763 : *countp = count;
3287 : 1766 : return vxids;
3288 : : }
3289 : :
3290 : : /*
3291 : : * Find a lock in the shared lock table and release it. It is the caller's
3292 : : * responsibility to verify that this is a sane thing to do. (For example, it
3293 : : * would be bad to release a lock here if there might still be a LOCALLOCK
3294 : : * object with pointers to it.)
3295 : : *
3296 : : * We currently use this in two situations: first, to release locks held by
3297 : : * prepared transactions on commit (see lock_twophase_postcommit); and second,
3298 : : * to release locks taken via the fast-path, transferred to the main hash
3299 : : * table, and then released (see LockReleaseAll).
3300 : : */
3301 : : static void
3302 : 2808 : LockRefindAndRelease(LockMethod lockMethodTable, PGPROC *proc,
3303 : : LOCKTAG *locktag, LOCKMODE lockmode,
3304 : : bool decrement_strong_lock_count)
3305 : : {
3306 : : LOCK *lock;
3307 : : PROCLOCK *proclock;
3308 : : PROCLOCKTAG proclocktag;
3309 : : uint32 hashcode;
3310 : : uint32 proclock_hashcode;
3311 : : LWLock *partitionLock;
3312 : : bool wakeupNeeded;
3313 : :
3314 : 2808 : hashcode = LockTagHashCode(locktag);
3315 : 2808 : partitionLock = LockHashPartitionLock(hashcode);
3316 : :
3317 : 2808 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
3318 : :
3319 : : /*
3320 : : * Re-find the lock object (it had better be there).
3321 : : */
3322 : 2808 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
3323 : : locktag,
3324 : : hashcode,
3325 : : HASH_FIND,
3326 : : NULL);
3327 [ - + ]: 2808 : if (!lock)
3328 [ # # ]: 0 : elog(PANIC, "failed to re-find shared lock object");
3329 : :
3330 : : /*
3331 : : * Re-find the proclock object (ditto).
3332 : : */
3333 : 2808 : proclocktag.myLock = lock;
3334 : 2808 : proclocktag.myProc = proc;
3335 : :
3336 : 2808 : proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
3337 : :
3338 : 2808 : proclock = (PROCLOCK *) hash_search_with_hash_value(LockMethodProcLockHash,
3339 : : &proclocktag,
3340 : : proclock_hashcode,
3341 : : HASH_FIND,
3342 : : NULL);
3343 [ - + ]: 2808 : if (!proclock)
3344 [ # # ]: 0 : elog(PANIC, "failed to re-find shared proclock object");
3345 : :
3346 : : /*
3347 : : * Double-check that we are actually holding a lock of the type we want to
3348 : : * release.
3349 : : */
3350 [ - + ]: 2808 : if (!(proclock->holdMask & LOCKBIT_ON(lockmode)))
3351 : : {
3352 : : PROCLOCK_PRINT("lock_twophase_postcommit: WRONGTYPE", proclock);
3353 : 0 : LWLockRelease(partitionLock);
3354 [ # # ]: 0 : elog(WARNING, "you don't own a lock of type %s",
3355 : : lockMethodTable->lockModeNames[lockmode]);
3356 : 0 : return;
3357 : : }
3358 : :
3359 : : /*
3360 : : * Do the releasing. CleanUpLock will waken any now-wakable waiters.
3361 : : */
3362 : 2808 : wakeupNeeded = UnGrantLock(lock, lockmode, proclock, lockMethodTable);
3363 : :
3364 : 2808 : CleanUpLock(lock, proclock,
3365 : : lockMethodTable, hashcode,
3366 : : wakeupNeeded);
3367 : :
3368 : 2808 : LWLockRelease(partitionLock);
3369 : :
3370 : : /*
3371 : : * Decrement strong lock count. This logic is needed only for 2PC.
3372 : : */
3373 [ + + ]: 2808 : if (decrement_strong_lock_count
3374 [ + - + + : 917 : && ConflictsWithRelationFastPath(locktag, lockmode))
+ + + + ]
3375 : : {
3376 : 116 : uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
3377 : :
3378 : 116 : SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
3379 : : Assert(FastPathStrongRelationLocks->count[fasthashcode] > 0);
3380 : 116 : FastPathStrongRelationLocks->count[fasthashcode]--;
3381 : 116 : SpinLockRelease(&FastPathStrongRelationLocks->mutex);
3382 : : }
3383 : : }
3384 : :
3385 : : /*
3386 : : * CheckForSessionAndXactLocks
3387 : : * Check to see if transaction holds both session-level and xact-level
3388 : : * locks on the same object; if so, throw an error.
3389 : : *
3390 : : * If we have both session- and transaction-level locks on the same object,
3391 : : * PREPARE TRANSACTION must fail. This should never happen with regular
3392 : : * locks, since we only take those at session level in some special operations
3393 : : * like VACUUM. It's possible to hit this with advisory locks, though.
3394 : : *
3395 : : * It would be nice if we could keep the session hold and give away the
3396 : : * transactional hold to the prepared xact. However, that would require two
3397 : : * PROCLOCK objects, and we cannot be sure that another PROCLOCK will be
3398 : : * available when it comes time for PostPrepare_Locks to do the deed.
3399 : : * So for now, we error out while we can still do so safely.
3400 : : *
3401 : : * Since the LOCALLOCK table stores a separate entry for each lockmode,
3402 : : * we can't implement this check by examining LOCALLOCK entries in isolation.
3403 : : * We must build a transient hashtable that is indexed by locktag only.
3404 : : */
3405 : : static void
3406 : 326 : CheckForSessionAndXactLocks(void)
3407 : : {
3408 : : typedef struct
3409 : : {
3410 : : LOCKTAG lock; /* identifies the lockable object */
3411 : : bool sessLock; /* is any lockmode held at session level? */
3412 : : bool xactLock; /* is any lockmode held at xact level? */
3413 : : } PerLockTagEntry;
3414 : :
3415 : : HASHCTL hash_ctl;
3416 : : HTAB *lockhtab;
3417 : : HASH_SEQ_STATUS status;
3418 : : LOCALLOCK *locallock;
3419 : :
3420 : : /* Create a local hash table keyed by LOCKTAG only */
3421 : 326 : hash_ctl.keysize = sizeof(LOCKTAG);
3422 : 326 : hash_ctl.entrysize = sizeof(PerLockTagEntry);
3423 : 326 : hash_ctl.hcxt = CurrentMemoryContext;
3424 : :
3425 : 326 : lockhtab = hash_create("CheckForSessionAndXactLocks table",
3426 : : 256, /* arbitrary initial size */
3427 : : &hash_ctl,
3428 : : HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
3429 : :
3430 : : /* Scan local lock table to find entries for each LOCKTAG */
3431 : 326 : hash_seq_init(&status, LockMethodLocalHash);
3432 : :
3433 [ + + ]: 1245 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3434 : : {
3435 : 921 : LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3436 : : PerLockTagEntry *hentry;
3437 : : bool found;
3438 : : int i;
3439 : :
3440 : : /*
3441 : : * Ignore VXID locks. We don't want those to be held by prepared
3442 : : * transactions, since they aren't meaningful after a restart.
3443 : : */
3444 [ - + ]: 921 : if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3445 : 0 : continue;
3446 : :
3447 : : /* Ignore it if we don't actually hold the lock */
3448 [ - + ]: 921 : if (locallock->nLocks <= 0)
3449 : 0 : continue;
3450 : :
3451 : : /* Otherwise, find or make an entry in lockhtab */
3452 : 921 : hentry = (PerLockTagEntry *) hash_search(lockhtab,
3453 : 921 : &locallock->tag.lock,
3454 : : HASH_ENTER, &found);
3455 [ + + ]: 921 : if (!found) /* initialize, if newly created */
3456 : 828 : hentry->sessLock = hentry->xactLock = false;
3457 : :
3458 : : /* Scan to see if we hold lock at session or xact level or both */
3459 [ + + ]: 1842 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
3460 : : {
3461 [ + + ]: 921 : if (lockOwners[i].owner == NULL)
3462 : 10 : hentry->sessLock = true;
3463 : : else
3464 : 911 : hentry->xactLock = true;
3465 : : }
3466 : :
3467 : : /*
3468 : : * We can throw error immediately when we see both types of locks; no
3469 : : * need to wait around to see if there are more violations.
3470 : : */
3471 [ + + + + ]: 921 : if (hentry->sessLock && hentry->xactLock)
3472 [ + - ]: 2 : ereport(ERROR,
3473 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3474 : : errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3475 : : }
3476 : :
3477 : : /* Success, so clean up */
3478 : 324 : hash_destroy(lockhtab);
3479 : 324 : }
3480 : :
3481 : : /*
3482 : : * AtPrepare_Locks
3483 : : * Do the preparatory work for a PREPARE: make 2PC state file records
3484 : : * for all locks currently held.
3485 : : *
3486 : : * Session-level locks are ignored, as are VXID locks.
3487 : : *
3488 : : * For the most part, we don't need to touch shared memory for this ---
3489 : : * all the necessary state information is in the locallock table.
3490 : : * Fast-path locks are an exception, however: we move any such locks to
3491 : : * the main table before allowing PREPARE TRANSACTION to succeed.
3492 : : */
3493 : : void
3494 : 326 : AtPrepare_Locks(void)
3495 : : {
3496 : : HASH_SEQ_STATUS status;
3497 : : LOCALLOCK *locallock;
3498 : :
3499 : : /* First, verify there aren't locks of both xact and session level */
3500 : 326 : CheckForSessionAndXactLocks();
3501 : :
3502 : : /* Now do the per-locallock cleanup work */
3503 : 324 : hash_seq_init(&status, LockMethodLocalHash);
3504 : :
3505 [ + + ]: 1239 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3506 : : {
3507 : : TwoPhaseLockRecord record;
3508 : 915 : LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3509 : : bool haveSessionLock;
3510 : : bool haveXactLock;
3511 : : int i;
3512 : :
3513 : : /*
3514 : : * Ignore VXID locks. We don't want those to be held by prepared
3515 : : * transactions, since they aren't meaningful after a restart.
3516 : : */
3517 [ - + ]: 915 : if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3518 : 8 : continue;
3519 : :
3520 : : /* Ignore it if we don't actually hold the lock */
3521 [ - + ]: 915 : if (locallock->nLocks <= 0)
3522 : 0 : continue;
3523 : :
3524 : : /* Scan to see whether we hold it at session or transaction level */
3525 : 915 : haveSessionLock = haveXactLock = false;
3526 [ + + ]: 1830 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
3527 : : {
3528 [ + + ]: 915 : if (lockOwners[i].owner == NULL)
3529 : 8 : haveSessionLock = true;
3530 : : else
3531 : 907 : haveXactLock = true;
3532 : : }
3533 : :
3534 : : /* Ignore it if we have only session lock */
3535 [ + + ]: 915 : if (!haveXactLock)
3536 : 8 : continue;
3537 : :
3538 : : /* This can't happen, because we already checked it */
3539 [ - + ]: 907 : if (haveSessionLock)
3540 [ # # ]: 0 : ereport(ERROR,
3541 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3542 : : errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3543 : :
3544 : : /*
3545 : : * If the local lock was taken via the fast-path, we need to move it
3546 : : * to the primary lock table, or just get a pointer to the existing
3547 : : * primary lock table entry if by chance it's already been
3548 : : * transferred.
3549 : : */
3550 [ + + ]: 907 : if (locallock->proclock == NULL)
3551 : : {
3552 : 348 : locallock->proclock = FastPathGetRelationLockEntry(locallock);
3553 : 348 : locallock->lock = locallock->proclock->tag.myLock;
3554 : : }
3555 : :
3556 : : /*
3557 : : * Arrange to not release any strong lock count held by this lock
3558 : : * entry. We must retain the count until the prepared transaction is
3559 : : * committed or rolled back.
3560 : : */
3561 : 907 : locallock->holdsStrongLockCount = false;
3562 : :
3563 : : /*
3564 : : * Create a 2PC record.
3565 : : */
3566 : 907 : memcpy(&(record.locktag), &(locallock->tag.lock), sizeof(LOCKTAG));
3567 : 907 : record.lockmode = locallock->tag.mode;
3568 : :
3569 : 907 : RegisterTwoPhaseRecord(TWOPHASE_RM_LOCK_ID, 0,
3570 : : &record, sizeof(TwoPhaseLockRecord));
3571 : : }
3572 : 324 : }
3573 : :
3574 : : /*
3575 : : * PostPrepare_Locks
3576 : : * Clean up after successful PREPARE
3577 : : *
3578 : : * Here, we want to transfer ownership of our locks to a dummy PGPROC
3579 : : * that's now associated with the prepared transaction, and we want to
3580 : : * clean out the corresponding entries in the LOCALLOCK table.
3581 : : *
3582 : : * Note: by removing the LOCALLOCK entries, we are leaving dangling
3583 : : * pointers in the transaction's resource owner. This is OK at the
3584 : : * moment since resowner.c doesn't try to free locks retail at a toplevel
3585 : : * transaction commit or abort. We could alternatively zero out nLocks
3586 : : * and leave the LOCALLOCK entries to be garbage-collected by LockReleaseAll,
3587 : : * but that probably costs more cycles.
3588 : : */
3589 : : void
3590 : 324 : PostPrepare_Locks(FullTransactionId fxid)
3591 : : {
3592 : 324 : PGPROC *newproc = TwoPhaseGetDummyProc(fxid, false);
3593 : : HASH_SEQ_STATUS status;
3594 : : LOCALLOCK *locallock;
3595 : : LOCK *lock;
3596 : : PROCLOCK *proclock;
3597 : : PROCLOCKTAG proclocktag;
3598 : : int partition;
3599 : :
3600 : : /* Can't prepare a lock group follower. */
3601 : : Assert(MyProc->lockGroupLeader == NULL ||
3602 : : MyProc->lockGroupLeader == MyProc);
3603 : :
3604 : : /* This is a critical section: any error means big trouble */
3605 : 324 : START_CRIT_SECTION();
3606 : :
3607 : : /*
3608 : : * First we run through the locallock table and get rid of unwanted
3609 : : * entries, then we scan the process's proclocks and transfer them to the
3610 : : * target proc.
3611 : : *
3612 : : * We do this separately because we may have multiple locallock entries
3613 : : * pointing to the same proclock, and we daren't end up with any dangling
3614 : : * pointers.
3615 : : */
3616 : 324 : hash_seq_init(&status, LockMethodLocalHash);
3617 : :
3618 [ + + ]: 1239 : while ((locallock = (LOCALLOCK *) hash_seq_search(&status)) != NULL)
3619 : : {
3620 : 915 : LOCALLOCKOWNER *lockOwners = locallock->lockOwners;
3621 : : bool haveSessionLock;
3622 : : bool haveXactLock;
3623 : : int i;
3624 : :
3625 [ + - - + ]: 915 : if (locallock->proclock == NULL || locallock->lock == NULL)
3626 : : {
3627 : : /*
3628 : : * We must've run out of shared memory while trying to set up this
3629 : : * lock. Just forget the local entry.
3630 : : */
3631 : : Assert(locallock->nLocks == 0);
3632 : 0 : RemoveLocalLock(locallock);
3633 : 0 : continue;
3634 : : }
3635 : :
3636 : : /* Ignore VXID locks */
3637 [ - + ]: 915 : if (locallock->tag.lock.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3638 : 0 : continue;
3639 : :
3640 : : /* Scan to see whether we hold it at session or transaction level */
3641 : 915 : haveSessionLock = haveXactLock = false;
3642 [ + + ]: 1830 : for (i = locallock->numLockOwners - 1; i >= 0; i--)
3643 : : {
3644 [ + + ]: 915 : if (lockOwners[i].owner == NULL)
3645 : 8 : haveSessionLock = true;
3646 : : else
3647 : 907 : haveXactLock = true;
3648 : : }
3649 : :
3650 : : /* Ignore it if we have only session lock */
3651 [ + + ]: 915 : if (!haveXactLock)
3652 : 8 : continue;
3653 : :
3654 : : /* This can't happen, because we already checked it */
3655 [ - + ]: 907 : if (haveSessionLock)
3656 [ # # ]: 0 : ereport(PANIC,
3657 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
3658 : : errmsg("cannot PREPARE while holding both session-level and transaction-level locks on the same object")));
3659 : :
3660 : : /* Mark the proclock to show we need to release this lockmode */
3661 [ + - ]: 907 : if (locallock->nLocks > 0)
3662 : 907 : locallock->proclock->releaseMask |= LOCKBIT_ON(locallock->tag.mode);
3663 : :
3664 : : /* And remove the locallock hashtable entry */
3665 : 907 : RemoveLocalLock(locallock);
3666 : : }
3667 : :
3668 : : /*
3669 : : * Now, scan each lock partition separately.
3670 : : */
3671 [ + + ]: 5508 : for (partition = 0; partition < NUM_LOCK_PARTITIONS; partition++)
3672 : : {
3673 : : LWLock *partitionLock;
3674 : 5184 : dlist_head *procLocks = &(MyProc->myProcLocks[partition]);
3675 : : dlist_mutable_iter proclock_iter;
3676 : :
3677 : 5184 : partitionLock = LockHashPartitionLockByIndex(partition);
3678 : :
3679 : : /*
3680 : : * If the proclock list for this partition is empty, we can skip
3681 : : * acquiring the partition lock. This optimization is safer than the
3682 : : * situation in LockReleaseAll, because we got rid of any fast-path
3683 : : * locks during AtPrepare_Locks, so there cannot be any case where
3684 : : * another backend is adding something to our lists now. For safety,
3685 : : * though, we code this the same way as in LockReleaseAll.
3686 : : */
3687 [ + + ]: 5184 : if (dlist_is_empty(procLocks))
3688 : 4380 : continue; /* needn't examine this partition */
3689 : :
3690 : 804 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
3691 : :
3692 [ + - + + ]: 1659 : dlist_foreach_modify(proclock_iter, procLocks)
3693 : : {
3694 : 855 : proclock = dlist_container(PROCLOCK, procLink, proclock_iter.cur);
3695 : :
3696 : : Assert(proclock->tag.myProc == MyProc);
3697 : :
3698 : 855 : lock = proclock->tag.myLock;
3699 : :
3700 : : /* Ignore VXID locks */
3701 [ + + ]: 855 : if (lock->tag.locktag_type == LOCKTAG_VIRTUALTRANSACTION)
3702 : 31 : continue;
3703 : :
3704 : : PROCLOCK_PRINT("PostPrepare_Locks", proclock);
3705 : : LOCK_PRINT("PostPrepare_Locks", lock, 0);
3706 : : Assert(lock->nRequested >= 0);
3707 : : Assert(lock->nGranted >= 0);
3708 : : Assert(lock->nGranted <= lock->nRequested);
3709 : : Assert((proclock->holdMask & ~lock->grantMask) == 0);
3710 : :
3711 : : /* Ignore it if nothing to release (must be a session lock) */
3712 [ + + ]: 824 : if (proclock->releaseMask == 0)
3713 : 8 : continue;
3714 : :
3715 : : /* Else we should be releasing all locks */
3716 [ - + ]: 816 : if (proclock->releaseMask != proclock->holdMask)
3717 [ # # ]: 0 : elog(PANIC, "we seem to have dropped a bit somewhere");
3718 : :
3719 : : /*
3720 : : * We cannot simply modify proclock->tag.myProc to reassign
3721 : : * ownership of the lock, because that's part of the hash key and
3722 : : * the proclock would then be in the wrong hash chain. Instead
3723 : : * use hash_update_hash_key. (We used to create a new hash entry,
3724 : : * but that risks out-of-memory failure if other processes are
3725 : : * busy making proclocks too.) We must unlink the proclock from
3726 : : * our procLink chain and put it into the new proc's chain, too.
3727 : : *
3728 : : * Note: the updated proclock hash key will still belong to the
3729 : : * same hash partition, cf proclock_hash(). So the partition lock
3730 : : * we already hold is sufficient for this.
3731 : : */
3732 : 816 : dlist_delete(&proclock->procLink);
3733 : :
3734 : : /*
3735 : : * Create the new hash key for the proclock.
3736 : : */
3737 : 816 : proclocktag.myLock = lock;
3738 : 816 : proclocktag.myProc = newproc;
3739 : :
3740 : : /*
3741 : : * Update groupLeader pointer to point to the new proc. (We'd
3742 : : * better not be a member of somebody else's lock group!)
3743 : : */
3744 : : Assert(proclock->groupLeader == proclock->tag.myProc);
3745 : 816 : proclock->groupLeader = newproc;
3746 : :
3747 : : /*
3748 : : * Update the proclock. We should not find any existing entry for
3749 : : * the same hash key, since there can be only one entry for any
3750 : : * given lock with my own proc.
3751 : : */
3752 [ - + ]: 816 : if (!hash_update_hash_key(LockMethodProcLockHash,
3753 : : proclock,
3754 : : &proclocktag))
3755 [ # # ]: 0 : elog(PANIC, "duplicate entry found while reassigning a prepared transaction's locks");
3756 : :
3757 : : /* Re-link into the new proc's proclock list */
3758 : 816 : dlist_push_tail(&newproc->myProcLocks[partition], &proclock->procLink);
3759 : :
3760 : : PROCLOCK_PRINT("PostPrepare_Locks: updated", proclock);
3761 : : } /* loop over PROCLOCKs within this partition */
3762 : :
3763 : 804 : LWLockRelease(partitionLock);
3764 : : } /* loop over partitions */
3765 : :
3766 : 324 : END_CRIT_SECTION();
3767 : 324 : }
3768 : :
3769 : :
3770 : : /*
3771 : : * GetLockStatusData - Return a summary of the lock manager's internal
3772 : : * status, for use in a user-level reporting function.
3773 : : *
3774 : : * The return data consists of an array of LockInstanceData objects,
3775 : : * which are a lightly abstracted version of the PROCLOCK data structures,
3776 : : * i.e. there is one entry for each unique lock and interested PGPROC.
3777 : : * It is the caller's responsibility to match up related items (such as
3778 : : * references to the same lockable object or PGPROC) if wanted.
3779 : : *
3780 : : * The design goal is to hold the LWLocks for as short a time as possible;
3781 : : * thus, this function simply makes a copy of the necessary data and releases
3782 : : * the locks, allowing the caller to contemplate and format the data for as
3783 : : * long as it pleases.
3784 : : */
3785 : : LockData *
3786 : 297 : GetLockStatusData(void)
3787 : : {
3788 : : LockData *data;
3789 : : PROCLOCK *proclock;
3790 : : HASH_SEQ_STATUS seqstat;
3791 : : int els;
3792 : : int el;
3793 : :
3794 : 297 : data = palloc_object(LockData);
3795 : :
3796 : : /* Guess how much space we'll need. */
3797 : 297 : els = MaxBackends;
3798 : 297 : el = 0;
3799 : 297 : data->locks = palloc_array(LockInstanceData, els);
3800 : :
3801 : : /*
3802 : : * First, we iterate through the per-backend fast-path arrays, locking
3803 : : * them one at a time. This might produce an inconsistent picture of the
3804 : : * system state, but taking all of those LWLocks at the same time seems
3805 : : * impractical (in particular, note MAX_SIMUL_LWLOCKS). It shouldn't
3806 : : * matter too much, because none of these locks can be involved in lock
3807 : : * conflicts anyway - anything that might must be present in the main lock
3808 : : * table. (For the same reason, we don't sweat about making leaderPid
3809 : : * completely valid. We cannot safely dereference another backend's
3810 : : * lockGroupLeader field without holding all lock partition locks, and
3811 : : * it's not worth that.)
3812 : : */
3813 [ + + ]: 44159 : for (uint32 i = 0; i < ProcGlobal->allProcCount; ++i)
3814 : : {
3815 : 43862 : PGPROC *proc = GetPGProcByNumber(i);
3816 : :
3817 : : /* Skip backends with pid=0, as they don't hold fast-path locks */
3818 [ + + ]: 43862 : if (proc->pid == 0)
3819 : 39641 : continue;
3820 : :
3821 : 4221 : LWLockAcquire(&proc->fpInfoLock, LW_SHARED);
3822 : :
3823 [ + + ]: 37989 : for (uint32 g = 0; g < FastPathLockGroupsPerBackend; g++)
3824 : : {
3825 : : /* Skip groups without registered fast-path locks */
3826 [ + + ]: 33768 : if (proc->fpLockBits[g] == 0)
3827 : 30924 : continue;
3828 : :
3829 [ + + ]: 48348 : for (int j = 0; j < FP_LOCK_SLOTS_PER_GROUP; j++)
3830 : : {
3831 : : LockInstanceData *instance;
3832 : 45504 : uint32 f = FAST_PATH_SLOT(g, j);
3833 : 45504 : uint32 lockbits = FAST_PATH_GET_BITS(proc, f);
3834 : :
3835 : : /* Skip unallocated slots */
3836 [ + + ]: 45504 : if (!lockbits)
3837 : 41442 : continue;
3838 : :
3839 [ + + ]: 4062 : if (el >= els)
3840 : : {
3841 : 4 : els += MaxBackends;
3842 : 4 : data->locks = (LockInstanceData *)
3843 : 4 : repalloc(data->locks, sizeof(LockInstanceData) * els);
3844 : : }
3845 : :
3846 : 4062 : instance = &data->locks[el];
3847 : 4062 : SET_LOCKTAG_RELATION(instance->locktag, proc->databaseId,
3848 : : proc->fpRelId[f]);
3849 : 4062 : instance->holdMask = lockbits << FAST_PATH_LOCKNUMBER_OFFSET;
3850 : 4062 : instance->waitLockMode = NoLock;
3851 : 4062 : instance->vxid.procNumber = proc->vxid.procNumber;
3852 : 4062 : instance->vxid.localTransactionId = proc->vxid.lxid;
3853 : 4062 : instance->pid = proc->pid;
3854 : 4062 : instance->leaderPid = proc->pid;
3855 : 4062 : instance->fastpath = true;
3856 : :
3857 : : /*
3858 : : * Successfully taking fast path lock means there were no
3859 : : * conflicting locks.
3860 : : */
3861 : 4062 : instance->waitStart = 0;
3862 : :
3863 : 4062 : el++;
3864 : : }
3865 : : }
3866 : :
3867 [ + + ]: 4221 : if (proc->fpVXIDLock)
3868 : : {
3869 : : VirtualTransactionId vxid;
3870 : : LockInstanceData *instance;
3871 : :
3872 [ + + ]: 1236 : if (el >= els)
3873 : : {
3874 : 2 : els += MaxBackends;
3875 : 2 : data->locks = (LockInstanceData *)
3876 : 2 : repalloc(data->locks, sizeof(LockInstanceData) * els);
3877 : : }
3878 : :
3879 : 1236 : vxid.procNumber = proc->vxid.procNumber;
3880 : 1236 : vxid.localTransactionId = proc->fpLocalTransactionId;
3881 : :
3882 : 1236 : instance = &data->locks[el];
3883 : 1236 : SET_LOCKTAG_VIRTUALTRANSACTION(instance->locktag, vxid);
3884 : 1236 : instance->holdMask = LOCKBIT_ON(ExclusiveLock);
3885 : 1236 : instance->waitLockMode = NoLock;
3886 : 1236 : instance->vxid.procNumber = proc->vxid.procNumber;
3887 : 1236 : instance->vxid.localTransactionId = proc->vxid.lxid;
3888 : 1236 : instance->pid = proc->pid;
3889 : 1236 : instance->leaderPid = proc->pid;
3890 : 1236 : instance->fastpath = true;
3891 : 1236 : instance->waitStart = 0;
3892 : :
3893 : 1236 : el++;
3894 : : }
3895 : :
3896 : 4221 : LWLockRelease(&proc->fpInfoLock);
3897 : : }
3898 : :
3899 : : /*
3900 : : * Next, acquire lock on the entire shared lock data structure. We do
3901 : : * this so that, at least for locks in the primary lock table, the state
3902 : : * will be self-consistent.
3903 : : *
3904 : : * Since this is a read-only operation, we take shared instead of
3905 : : * exclusive lock. There's not a whole lot of point to this, because all
3906 : : * the normal operations require exclusive lock, but it doesn't hurt
3907 : : * anything either. It will at least allow two backends to do
3908 : : * GetLockStatusData in parallel.
3909 : : *
3910 : : * Must grab LWLocks in partition-number order to avoid LWLock deadlock.
3911 : : */
3912 [ + + ]: 5049 : for (int i = 0; i < NUM_LOCK_PARTITIONS; i++)
3913 : 4752 : LWLockAcquire(LockHashPartitionLockByIndex(i), LW_SHARED);
3914 : :
3915 : : /* Now we can safely count the number of proclocks */
3916 : 297 : data->nelements = el + hash_get_num_entries(LockMethodProcLockHash);
3917 [ + + ]: 297 : if (data->nelements > els)
3918 : : {
3919 : 11 : els = data->nelements;
3920 : 11 : data->locks = (LockInstanceData *)
3921 : 11 : repalloc(data->locks, sizeof(LockInstanceData) * els);
3922 : : }
3923 : :
3924 : : /* Now scan the tables to copy the data */
3925 : 297 : hash_seq_init(&seqstat, LockMethodProcLockHash);
3926 : :
3927 [ + + ]: 2917 : while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
3928 : : {
3929 : 2620 : PGPROC *proc = proclock->tag.myProc;
3930 : 2620 : LOCK *lock = proclock->tag.myLock;
3931 : 2620 : LockInstanceData *instance = &data->locks[el];
3932 : :
3933 : 2620 : memcpy(&instance->locktag, &lock->tag, sizeof(LOCKTAG));
3934 : 2620 : instance->holdMask = proclock->holdMask;
3935 [ + + ]: 2620 : if (proc->waitLock == proclock->tag.myLock)
3936 : 11 : instance->waitLockMode = proc->waitLockMode;
3937 : : else
3938 : 2609 : instance->waitLockMode = NoLock;
3939 : 2620 : instance->vxid.procNumber = proc->vxid.procNumber;
3940 : 2620 : instance->vxid.localTransactionId = proc->vxid.lxid;
3941 : 2620 : instance->pid = proc->pid;
3942 : 2620 : instance->leaderPid = proclock->groupLeader->pid;
3943 : 2620 : instance->fastpath = false;
3944 : 2620 : instance->waitStart = (TimestampTz) pg_atomic_read_u64(&proc->waitStart);
3945 : :
3946 : 2620 : el++;
3947 : : }
3948 : :
3949 : : /*
3950 : : * And release locks. We do this in reverse order for two reasons: (1)
3951 : : * Anyone else who needs more than one of the locks will be trying to lock
3952 : : * them in increasing order; we don't want to release the other process
3953 : : * until it can get all the locks it needs. (2) This avoids O(N^2)
3954 : : * behavior inside LWLockRelease.
3955 : : */
3956 [ + + ]: 5049 : for (int i = NUM_LOCK_PARTITIONS; --i >= 0;)
3957 : 4752 : LWLockRelease(LockHashPartitionLockByIndex(i));
3958 : :
3959 : : Assert(el == data->nelements);
3960 : :
3961 : 297 : return data;
3962 : : }
3963 : :
3964 : : /*
3965 : : * GetBlockerStatusData - Return a summary of the lock manager's state
3966 : : * concerning locks that are blocking the specified PID or any member of
3967 : : * the PID's lock group, for use in a user-level reporting function.
3968 : : *
3969 : : * For each PID within the lock group that is awaiting some heavyweight lock,
3970 : : * the return data includes an array of LockInstanceData objects, which are
3971 : : * the same data structure used by GetLockStatusData; but unlike that function,
3972 : : * this one reports only the PROCLOCKs associated with the lock that that PID
3973 : : * is blocked on. (Hence, all the locktags should be the same for any one
3974 : : * blocked PID.) In addition, we return an array of the PIDs of those backends
3975 : : * that are ahead of the blocked PID in the lock's wait queue. These can be
3976 : : * compared with the PIDs in the LockInstanceData objects to determine which
3977 : : * waiters are ahead of or behind the blocked PID in the queue.
3978 : : *
3979 : : * If blocked_pid isn't a valid backend PID or nothing in its lock group is
3980 : : * waiting on any heavyweight lock, return empty arrays.
3981 : : *
3982 : : * The design goal is to hold the LWLocks for as short a time as possible;
3983 : : * thus, this function simply makes a copy of the necessary data and releases
3984 : : * the locks, allowing the caller to contemplate and format the data for as
3985 : : * long as it pleases.
3986 : : */
3987 : : BlockedProcsData *
3988 : 1742 : GetBlockerStatusData(int blocked_pid)
3989 : : {
3990 : : BlockedProcsData *data;
3991 : : PGPROC *proc;
3992 : : int i;
3993 : :
3994 : 1742 : data = palloc_object(BlockedProcsData);
3995 : :
3996 : : /*
3997 : : * Guess how much space we'll need, and preallocate. Most of the time
3998 : : * this will avoid needing to do repalloc while holding the LWLocks. (We
3999 : : * assume, but check with an Assert, that MaxBackends is enough entries
4000 : : * for the procs[] array; the other two could need enlargement, though.)
4001 : : */
4002 : 1742 : data->nprocs = data->nlocks = data->npids = 0;
4003 : 1742 : data->maxprocs = data->maxlocks = data->maxpids = MaxBackends;
4004 : 1742 : data->procs = palloc_array(BlockedProcData, data->maxprocs);
4005 : 1742 : data->locks = palloc_array(LockInstanceData, data->maxlocks);
4006 : 1742 : data->waiter_pids = palloc_array(int, data->maxpids);
4007 : :
4008 : : /*
4009 : : * In order to search the ProcArray for blocked_pid and assume that that
4010 : : * entry won't immediately disappear under us, we must hold ProcArrayLock.
4011 : : * In addition, to examine the lock grouping fields of any other backend,
4012 : : * we must hold all the hash partition locks. (Only one of those locks is
4013 : : * actually relevant for any one lock group, but we can't know which one
4014 : : * ahead of time.) It's fairly annoying to hold all those locks
4015 : : * throughout this, but it's no worse than GetLockStatusData(), and it
4016 : : * does have the advantage that we're guaranteed to return a
4017 : : * self-consistent instantaneous state.
4018 : : */
4019 : 1742 : LWLockAcquire(ProcArrayLock, LW_SHARED);
4020 : :
4021 : 1742 : proc = BackendPidGetProcWithLock(blocked_pid);
4022 : :
4023 : : /* Nothing to do if it's gone */
4024 [ + - ]: 1742 : if (proc != NULL)
4025 : : {
4026 : : /*
4027 : : * Acquire lock on the entire shared lock data structure. See notes
4028 : : * in GetLockStatusData().
4029 : : */
4030 [ + + ]: 29614 : for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
4031 : 27872 : LWLockAcquire(LockHashPartitionLockByIndex(i), LW_SHARED);
4032 : :
4033 [ + + ]: 1742 : if (proc->lockGroupLeader == NULL)
4034 : : {
4035 : : /* Easy case, proc is not a lock group member */
4036 : 1578 : GetSingleProcBlockerStatusData(proc, data);
4037 : : }
4038 : : else
4039 : : {
4040 : : /* Examine all procs in proc's lock group */
4041 : : dlist_iter iter;
4042 : :
4043 [ + - + + ]: 388 : dlist_foreach(iter, &proc->lockGroupLeader->lockGroupMembers)
4044 : : {
4045 : : PGPROC *memberProc;
4046 : :
4047 : 224 : memberProc = dlist_container(PGPROC, lockGroupLink, iter.cur);
4048 : 224 : GetSingleProcBlockerStatusData(memberProc, data);
4049 : : }
4050 : : }
4051 : :
4052 : : /*
4053 : : * And release locks. See notes in GetLockStatusData().
4054 : : */
4055 [ + + ]: 29614 : for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
4056 : 27872 : LWLockRelease(LockHashPartitionLockByIndex(i));
4057 : :
4058 : : Assert(data->nprocs <= data->maxprocs);
4059 : : }
4060 : :
4061 : 1742 : LWLockRelease(ProcArrayLock);
4062 : :
4063 : 1742 : return data;
4064 : : }
4065 : :
4066 : : /* Accumulate data about one possibly-blocked proc for GetBlockerStatusData */
4067 : : static void
4068 : 1802 : GetSingleProcBlockerStatusData(PGPROC *blocked_proc, BlockedProcsData *data)
4069 : : {
4070 : 1802 : LOCK *theLock = blocked_proc->waitLock;
4071 : : BlockedProcData *bproc;
4072 : : dlist_iter proclock_iter;
4073 : : dlist_iter proc_iter;
4074 : : dclist_head *waitQueue;
4075 : : int queue_size;
4076 : :
4077 : : /* Nothing to do if this proc is not blocked */
4078 [ + + ]: 1802 : if (theLock == NULL)
4079 : 515 : return;
4080 : :
4081 : : /* Set up a procs[] element */
4082 : 1287 : bproc = &data->procs[data->nprocs++];
4083 : 1287 : bproc->pid = blocked_proc->pid;
4084 : 1287 : bproc->first_lock = data->nlocks;
4085 : 1287 : bproc->first_waiter = data->npids;
4086 : :
4087 : : /*
4088 : : * We may ignore the proc's fast-path arrays, since nothing in those could
4089 : : * be related to a contended lock.
4090 : : */
4091 : :
4092 : : /* Collect all PROCLOCKs associated with theLock */
4093 [ + - + + ]: 3908 : dlist_foreach(proclock_iter, &theLock->procLocks)
4094 : : {
4095 : 2621 : PROCLOCK *proclock =
4096 : 2621 : dlist_container(PROCLOCK, lockLink, proclock_iter.cur);
4097 : 2621 : PGPROC *proc = proclock->tag.myProc;
4098 : 2621 : LOCK *lock = proclock->tag.myLock;
4099 : : LockInstanceData *instance;
4100 : :
4101 [ - + ]: 2621 : if (data->nlocks >= data->maxlocks)
4102 : : {
4103 : 0 : data->maxlocks += MaxBackends;
4104 : 0 : data->locks = (LockInstanceData *)
4105 : 0 : repalloc(data->locks, sizeof(LockInstanceData) * data->maxlocks);
4106 : : }
4107 : :
4108 : 2621 : instance = &data->locks[data->nlocks];
4109 : 2621 : memcpy(&instance->locktag, &lock->tag, sizeof(LOCKTAG));
4110 : 2621 : instance->holdMask = proclock->holdMask;
4111 [ + + ]: 2621 : if (proc->waitLock == lock)
4112 : 1329 : instance->waitLockMode = proc->waitLockMode;
4113 : : else
4114 : 1292 : instance->waitLockMode = NoLock;
4115 : 2621 : instance->vxid.procNumber = proc->vxid.procNumber;
4116 : 2621 : instance->vxid.localTransactionId = proc->vxid.lxid;
4117 : 2621 : instance->pid = proc->pid;
4118 : 2621 : instance->leaderPid = proclock->groupLeader->pid;
4119 : 2621 : instance->fastpath = false;
4120 : 2621 : data->nlocks++;
4121 : : }
4122 : :
4123 : : /* Enlarge waiter_pids[] if it's too small to hold all wait queue PIDs */
4124 : 1287 : waitQueue = &(theLock->waitProcs);
4125 : 1287 : queue_size = dclist_count(waitQueue);
4126 : :
4127 [ - + ]: 1287 : if (queue_size > data->maxpids - data->npids)
4128 : : {
4129 : 0 : data->maxpids = Max(data->maxpids + MaxBackends,
4130 : : data->npids + queue_size);
4131 : 0 : data->waiter_pids = (int *) repalloc(data->waiter_pids,
4132 : 0 : sizeof(int) * data->maxpids);
4133 : : }
4134 : :
4135 : : /* Collect PIDs from the lock's wait queue, stopping at blocked_proc */
4136 [ + - + - ]: 1307 : dclist_foreach(proc_iter, waitQueue)
4137 : : {
4138 : 1307 : PGPROC *queued_proc = dlist_container(PGPROC, waitLink, proc_iter.cur);
4139 : :
4140 [ + + ]: 1307 : if (queued_proc == blocked_proc)
4141 : 1287 : break;
4142 : 20 : data->waiter_pids[data->npids++] = queued_proc->pid;
4143 : : }
4144 : :
4145 : 1287 : bproc->num_locks = data->nlocks - bproc->first_lock;
4146 : 1287 : bproc->num_waiters = data->npids - bproc->first_waiter;
4147 : : }
4148 : :
4149 : : /*
4150 : : * Returns a list of currently held AccessExclusiveLocks, for use by
4151 : : * LogStandbySnapshot(). The result is a palloc'd array,
4152 : : * with the number of elements returned into *nlocks.
4153 : : *
4154 : : * XXX This currently takes a lock on all partitions of the lock table,
4155 : : * but it's possible to do better. By reference counting locks and storing
4156 : : * the value in the ProcArray entry for each backend we could tell if any
4157 : : * locks need recording without having to acquire the partition locks and
4158 : : * scan the lock table. Whether that's worth the additional overhead
4159 : : * is pretty dubious though.
4160 : : */
4161 : : xl_standby_lock *
4162 : 1545 : GetRunningTransactionLocks(int *nlocks)
4163 : : {
4164 : : xl_standby_lock *accessExclusiveLocks;
4165 : : PROCLOCK *proclock;
4166 : : HASH_SEQ_STATUS seqstat;
4167 : : int i;
4168 : : int index;
4169 : : int els;
4170 : :
4171 : : /*
4172 : : * Acquire lock on the entire shared lock data structure.
4173 : : *
4174 : : * Must grab LWLocks in partition-number order to avoid LWLock deadlock.
4175 : : */
4176 [ + + ]: 26265 : for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
4177 : 24720 : LWLockAcquire(LockHashPartitionLockByIndex(i), LW_SHARED);
4178 : :
4179 : : /* Now we can safely count the number of proclocks */
4180 : 1545 : els = hash_get_num_entries(LockMethodProcLockHash);
4181 : :
4182 : : /*
4183 : : * Allocating enough space for all locks in the lock table is overkill,
4184 : : * but it's more convenient and faster than having to enlarge the array.
4185 : : */
4186 : 1545 : accessExclusiveLocks = palloc(els * sizeof(xl_standby_lock));
4187 : :
4188 : : /* Now scan the tables to copy the data */
4189 : 1545 : hash_seq_init(&seqstat, LockMethodProcLockHash);
4190 : :
4191 : : /*
4192 : : * If lock is a currently granted AccessExclusiveLock then it will have
4193 : : * just one proclock holder, so locks are never accessed twice in this
4194 : : * particular case. Don't copy this code for use elsewhere because in the
4195 : : * general case this will give you duplicate locks when looking at
4196 : : * non-exclusive lock types.
4197 : : */
4198 : 1545 : index = 0;
4199 [ + + ]: 7150 : while ((proclock = (PROCLOCK *) hash_seq_search(&seqstat)))
4200 : : {
4201 : : /* make sure this definition matches the one used in LockAcquire */
4202 [ + + ]: 5605 : if ((proclock->holdMask & LOCKBIT_ON(AccessExclusiveLock)) &&
4203 [ + + ]: 2513 : proclock->tag.myLock->tag.locktag_type == LOCKTAG_RELATION)
4204 : : {
4205 : 1761 : PGPROC *proc = proclock->tag.myProc;
4206 : 1761 : LOCK *lock = proclock->tag.myLock;
4207 : 1761 : TransactionId xid = proc->xid;
4208 : :
4209 : : /*
4210 : : * Don't record locks for transactions if we know they have
4211 : : * already issued their WAL record for commit but not yet released
4212 : : * lock. It is still possible that we see locks held by already
4213 : : * complete transactions, if they haven't yet zeroed their xids.
4214 : : */
4215 [ + + ]: 1761 : if (!TransactionIdIsValid(xid))
4216 : 6 : continue;
4217 : :
4218 : 1755 : accessExclusiveLocks[index].xid = xid;
4219 : 1755 : accessExclusiveLocks[index].dbOid = lock->tag.locktag_field1;
4220 : 1755 : accessExclusiveLocks[index].relOid = lock->tag.locktag_field2;
4221 : :
4222 : 1755 : index++;
4223 : : }
4224 : : }
4225 : :
4226 : : Assert(index <= els);
4227 : :
4228 : : /*
4229 : : * And release locks. We do this in reverse order for two reasons: (1)
4230 : : * Anyone else who needs more than one of the locks will be trying to lock
4231 : : * them in increasing order; we don't want to release the other process
4232 : : * until it can get all the locks it needs. (2) This avoids O(N^2)
4233 : : * behavior inside LWLockRelease.
4234 : : */
4235 [ + + ]: 26265 : for (i = NUM_LOCK_PARTITIONS; --i >= 0;)
4236 : 24720 : LWLockRelease(LockHashPartitionLockByIndex(i));
4237 : :
4238 : 1545 : *nlocks = index;
4239 : 1545 : return accessExclusiveLocks;
4240 : : }
4241 : :
4242 : : /* Provide the textual name of any lock mode */
4243 : : const char *
4244 : 10430 : GetLockmodeName(LOCKMETHODID lockmethodid, LOCKMODE mode)
4245 : : {
4246 : : Assert(lockmethodid > 0 && lockmethodid < lengthof(LockMethods));
4247 : : Assert(mode > 0 && mode <= LockMethods[lockmethodid]->numLockModes);
4248 : 10430 : return LockMethods[lockmethodid]->lockModeNames[mode];
4249 : : }
4250 : :
4251 : : #ifdef LOCK_DEBUG
4252 : : /*
4253 : : * Dump all locks in the given proc's myProcLocks lists.
4254 : : *
4255 : : * Caller is responsible for having acquired appropriate LWLocks.
4256 : : */
4257 : : void
4258 : : DumpLocks(PGPROC *proc)
4259 : : {
4260 : : int i;
4261 : :
4262 : : if (proc == NULL)
4263 : : return;
4264 : :
4265 : : if (proc->waitLock)
4266 : : LOCK_PRINT("DumpLocks: waiting on", proc->waitLock, 0);
4267 : :
4268 : : for (i = 0; i < NUM_LOCK_PARTITIONS; i++)
4269 : : {
4270 : : dlist_head *procLocks = &proc->myProcLocks[i];
4271 : : dlist_iter iter;
4272 : :
4273 : : dlist_foreach(iter, procLocks)
4274 : : {
4275 : : PROCLOCK *proclock = dlist_container(PROCLOCK, procLink, iter.cur);
4276 : : LOCK *lock = proclock->tag.myLock;
4277 : :
4278 : : Assert(proclock->tag.myProc == proc);
4279 : : PROCLOCK_PRINT("DumpLocks", proclock);
4280 : : LOCK_PRINT("DumpLocks", lock, 0);
4281 : : }
4282 : : }
4283 : : }
4284 : :
4285 : : /*
4286 : : * Dump all lmgr locks.
4287 : : *
4288 : : * Caller is responsible for having acquired appropriate LWLocks.
4289 : : */
4290 : : void
4291 : : DumpAllLocks(void)
4292 : : {
4293 : : PGPROC *proc;
4294 : : PROCLOCK *proclock;
4295 : : LOCK *lock;
4296 : : HASH_SEQ_STATUS status;
4297 : :
4298 : : proc = MyProc;
4299 : :
4300 : : if (proc && proc->waitLock)
4301 : : LOCK_PRINT("DumpAllLocks: waiting on", proc->waitLock, 0);
4302 : :
4303 : : hash_seq_init(&status, LockMethodProcLockHash);
4304 : :
4305 : : while ((proclock = (PROCLOCK *) hash_seq_search(&status)) != NULL)
4306 : : {
4307 : : PROCLOCK_PRINT("DumpAllLocks", proclock);
4308 : :
4309 : : lock = proclock->tag.myLock;
4310 : : if (lock)
4311 : : LOCK_PRINT("DumpAllLocks", lock, 0);
4312 : : else
4313 : : elog(LOG, "DumpAllLocks: proclock->tag.myLock = NULL");
4314 : : }
4315 : : }
4316 : : #endif /* LOCK_DEBUG */
4317 : :
4318 : : /*
4319 : : * LOCK 2PC resource manager's routines
4320 : : */
4321 : :
4322 : : /*
4323 : : * Re-acquire a lock belonging to a transaction that was prepared.
4324 : : *
4325 : : * Because this function is run at db startup, re-acquiring the locks should
4326 : : * never conflict with running transactions because there are none. We
4327 : : * assume that the lock state represented by the stored 2PC files is legal.
4328 : : *
4329 : : * When switching from Hot Standby mode to normal operation, the locks will
4330 : : * be already held by the startup process. The locks are acquired for the new
4331 : : * procs without checking for conflicts, so we don't get a conflict between the
4332 : : * startup process and the dummy procs, even though we will momentarily have
4333 : : * a situation where two procs are holding the same AccessExclusiveLock,
4334 : : * which isn't normally possible because the conflict. If we're in standby
4335 : : * mode, but a recovery snapshot hasn't been established yet, it's possible
4336 : : * that some but not all of the locks are already held by the startup process.
4337 : : *
4338 : : * This approach is simple, but also a bit dangerous, because if there isn't
4339 : : * enough shared memory to acquire the locks, an error will be thrown, which
4340 : : * is promoted to FATAL and recovery will abort, bringing down postmaster.
4341 : : * A safer approach would be to transfer the locks like we do in
4342 : : * AtPrepare_Locks, but then again, in hot standby mode it's possible for
4343 : : * read-only backends to use up all the shared lock memory anyway, so that
4344 : : * replaying the WAL record that needs to acquire a lock will throw an error
4345 : : * and PANIC anyway.
4346 : : */
4347 : : void
4348 : 96 : lock_twophase_recover(FullTransactionId fxid, uint16 info,
4349 : : void *recdata, uint32 len)
4350 : : {
4351 : 96 : TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4352 : 96 : PGPROC *proc = TwoPhaseGetDummyProc(fxid, false);
4353 : : LOCKTAG *locktag;
4354 : : LOCKMODE lockmode;
4355 : : LOCKMETHODID lockmethodid;
4356 : : LOCK *lock;
4357 : : PROCLOCK *proclock;
4358 : : PROCLOCKTAG proclocktag;
4359 : : bool found;
4360 : : uint32 hashcode;
4361 : : uint32 proclock_hashcode;
4362 : : int partition;
4363 : : LWLock *partitionLock;
4364 : : LockMethod lockMethodTable;
4365 : :
4366 : : Assert(len == sizeof(TwoPhaseLockRecord));
4367 : 96 : locktag = &rec->locktag;
4368 : 96 : lockmode = rec->lockmode;
4369 : 96 : lockmethodid = locktag->locktag_lockmethodid;
4370 : :
4371 [ + - - + ]: 96 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4372 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4373 : 96 : lockMethodTable = LockMethods[lockmethodid];
4374 : :
4375 : 96 : hashcode = LockTagHashCode(locktag);
4376 : 96 : partition = LockHashPartition(hashcode);
4377 : 96 : partitionLock = LockHashPartitionLock(hashcode);
4378 : :
4379 : 96 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4380 : :
4381 : : /*
4382 : : * Find or create a lock with this tag.
4383 : : */
4384 : 96 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
4385 : : locktag,
4386 : : hashcode,
4387 : : HASH_ENTER_NULL,
4388 : : &found);
4389 [ - + ]: 96 : if (!lock)
4390 : : {
4391 : 0 : LWLockRelease(partitionLock);
4392 [ # # ]: 0 : ereport(ERROR,
4393 : : (errcode(ERRCODE_OUT_OF_MEMORY),
4394 : : errmsg("out of shared memory"),
4395 : : errhint("You might need to increase \"%s\".", "max_locks_per_transaction")));
4396 : : }
4397 : :
4398 : : /*
4399 : : * if it's a new lock object, initialize it
4400 : : */
4401 [ + + ]: 96 : if (!found)
4402 : : {
4403 : 84 : lock->grantMask = 0;
4404 : 84 : lock->waitMask = 0;
4405 : 84 : dlist_init(&lock->procLocks);
4406 : 84 : dclist_init(&lock->waitProcs);
4407 : 84 : lock->nRequested = 0;
4408 : 84 : lock->nGranted = 0;
4409 [ + - + - : 504 : MemSet(lock->requested, 0, sizeof(int) * MAX_LOCKMODES);
+ - + - +
+ ]
4410 [ - + - - : 84 : MemSet(lock->granted, 0, sizeof(int) * MAX_LOCKMODES);
- - - - -
- ]
4411 : : LOCK_PRINT("lock_twophase_recover: new", lock, lockmode);
4412 : : }
4413 : : else
4414 : : {
4415 : : LOCK_PRINT("lock_twophase_recover: found", lock, lockmode);
4416 : : Assert((lock->nRequested >= 0) && (lock->requested[lockmode] >= 0));
4417 : : Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
4418 : : Assert(lock->nGranted <= lock->nRequested);
4419 : : }
4420 : :
4421 : : /*
4422 : : * Create the hash key for the proclock table.
4423 : : */
4424 : 96 : proclocktag.myLock = lock;
4425 : 96 : proclocktag.myProc = proc;
4426 : :
4427 : 96 : proclock_hashcode = ProcLockHashCode(&proclocktag, hashcode);
4428 : :
4429 : : /*
4430 : : * Find or create a proclock entry with this tag
4431 : : */
4432 : 96 : proclock = (PROCLOCK *) hash_search_with_hash_value(LockMethodProcLockHash,
4433 : : &proclocktag,
4434 : : proclock_hashcode,
4435 : : HASH_ENTER_NULL,
4436 : : &found);
4437 [ - + ]: 96 : if (!proclock)
4438 : : {
4439 : : /* Oops, not enough shmem for the proclock */
4440 [ # # ]: 0 : if (lock->nRequested == 0)
4441 : : {
4442 : : /*
4443 : : * There are no other requestors of this lock, so garbage-collect
4444 : : * the lock object. We *must* do this to avoid a permanent leak
4445 : : * of shared memory, because there won't be anything to cause
4446 : : * anyone to release the lock object later.
4447 : : */
4448 : : Assert(dlist_is_empty(&lock->procLocks));
4449 [ # # ]: 0 : if (!hash_search_with_hash_value(LockMethodLockHash,
4450 : 0 : &(lock->tag),
4451 : : hashcode,
4452 : : HASH_REMOVE,
4453 : : NULL))
4454 [ # # ]: 0 : elog(PANIC, "lock table corrupted");
4455 : : }
4456 : 0 : LWLockRelease(partitionLock);
4457 [ # # ]: 0 : ereport(ERROR,
4458 : : (errcode(ERRCODE_OUT_OF_MEMORY),
4459 : : errmsg("out of shared memory"),
4460 : : errhint("You might need to increase \"%s\".", "max_locks_per_transaction")));
4461 : : }
4462 : :
4463 : : /*
4464 : : * If new, initialize the new entry
4465 : : */
4466 [ + + ]: 96 : if (!found)
4467 : : {
4468 : : Assert(proc->lockGroupLeader == NULL);
4469 : 88 : proclock->groupLeader = proc;
4470 : 88 : proclock->holdMask = 0;
4471 : 88 : proclock->releaseMask = 0;
4472 : : /* Add proclock to appropriate lists */
4473 : 88 : dlist_push_tail(&lock->procLocks, &proclock->lockLink);
4474 : 88 : dlist_push_tail(&proc->myProcLocks[partition],
4475 : : &proclock->procLink);
4476 : : PROCLOCK_PRINT("lock_twophase_recover: new", proclock);
4477 : : }
4478 : : else
4479 : : {
4480 : : PROCLOCK_PRINT("lock_twophase_recover: found", proclock);
4481 : : Assert((proclock->holdMask & ~lock->grantMask) == 0);
4482 : : }
4483 : :
4484 : : /*
4485 : : * lock->nRequested and lock->requested[] count the total number of
4486 : : * requests, whether granted or waiting, so increment those immediately.
4487 : : */
4488 : 96 : lock->nRequested++;
4489 : 96 : lock->requested[lockmode]++;
4490 : : Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
4491 : :
4492 : : /*
4493 : : * We shouldn't already hold the desired lock.
4494 : : */
4495 [ - + ]: 96 : if (proclock->holdMask & LOCKBIT_ON(lockmode))
4496 [ # # ]: 0 : elog(ERROR, "lock %s on object %u/%u/%u is already held",
4497 : : lockMethodTable->lockModeNames[lockmode],
4498 : : lock->tag.locktag_field1, lock->tag.locktag_field2,
4499 : : lock->tag.locktag_field3);
4500 : :
4501 : : /*
4502 : : * We ignore any possible conflicts and just grant ourselves the lock. Not
4503 : : * only because we don't bother, but also to avoid deadlocks when
4504 : : * switching from standby to normal mode. See function comment.
4505 : : */
4506 : 96 : GrantLock(lock, proclock, lockmode);
4507 : :
4508 : : /*
4509 : : * Bump strong lock count, to make sure any fast-path lock requests won't
4510 : : * be granted without consulting the primary lock table.
4511 : : */
4512 [ + - + + : 96 : if (ConflictsWithRelationFastPath(&lock->tag, lockmode))
+ - + + ]
4513 : : {
4514 : 18 : uint32 fasthashcode = FastPathStrongLockHashPartition(hashcode);
4515 : :
4516 : 18 : SpinLockAcquire(&FastPathStrongRelationLocks->mutex);
4517 : 18 : FastPathStrongRelationLocks->count[fasthashcode]++;
4518 : 18 : SpinLockRelease(&FastPathStrongRelationLocks->mutex);
4519 : : }
4520 : :
4521 : 96 : LWLockRelease(partitionLock);
4522 : 96 : }
4523 : :
4524 : : /*
4525 : : * Re-acquire a lock belonging to a transaction that was prepared, when
4526 : : * starting up into hot standby mode.
4527 : : */
4528 : : void
4529 : 0 : lock_twophase_standby_recover(FullTransactionId fxid, uint16 info,
4530 : : void *recdata, uint32 len)
4531 : : {
4532 : 0 : TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4533 : : LOCKTAG *locktag;
4534 : : LOCKMODE lockmode;
4535 : : LOCKMETHODID lockmethodid;
4536 : :
4537 : : Assert(len == sizeof(TwoPhaseLockRecord));
4538 : 0 : locktag = &rec->locktag;
4539 : 0 : lockmode = rec->lockmode;
4540 : 0 : lockmethodid = locktag->locktag_lockmethodid;
4541 : :
4542 [ # # # # ]: 0 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4543 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4544 : :
4545 [ # # ]: 0 : if (lockmode == AccessExclusiveLock &&
4546 [ # # ]: 0 : locktag->locktag_type == LOCKTAG_RELATION)
4547 : : {
4548 : 0 : StandbyAcquireAccessExclusiveLock(XidFromFullTransactionId(fxid),
4549 : : locktag->locktag_field1 /* dboid */ ,
4550 : : locktag->locktag_field2 /* reloid */ );
4551 : : }
4552 : 0 : }
4553 : :
4554 : :
4555 : : /*
4556 : : * 2PC processing routine for COMMIT PREPARED case.
4557 : : *
4558 : : * Find and release the lock indicated by the 2PC record.
4559 : : */
4560 : : void
4561 : 917 : lock_twophase_postcommit(FullTransactionId fxid, uint16 info,
4562 : : void *recdata, uint32 len)
4563 : : {
4564 : 917 : TwoPhaseLockRecord *rec = (TwoPhaseLockRecord *) recdata;
4565 : 917 : PGPROC *proc = TwoPhaseGetDummyProc(fxid, true);
4566 : : LOCKTAG *locktag;
4567 : : LOCKMETHODID lockmethodid;
4568 : : LockMethod lockMethodTable;
4569 : :
4570 : : Assert(len == sizeof(TwoPhaseLockRecord));
4571 : 917 : locktag = &rec->locktag;
4572 : 917 : lockmethodid = locktag->locktag_lockmethodid;
4573 : :
4574 [ + - - + ]: 917 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4575 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4576 : 917 : lockMethodTable = LockMethods[lockmethodid];
4577 : :
4578 : 917 : LockRefindAndRelease(lockMethodTable, proc, locktag, rec->lockmode, true);
4579 : 917 : }
4580 : :
4581 : : /*
4582 : : * 2PC processing routine for ROLLBACK PREPARED case.
4583 : : *
4584 : : * This is actually just the same as the COMMIT case.
4585 : : */
4586 : : void
4587 : 186 : lock_twophase_postabort(FullTransactionId fxid, uint16 info,
4588 : : void *recdata, uint32 len)
4589 : : {
4590 : 186 : lock_twophase_postcommit(fxid, info, recdata, len);
4591 : 186 : }
4592 : :
4593 : : /*
4594 : : * VirtualXactLockTableInsert
4595 : : *
4596 : : * Take vxid lock via the fast-path. There can't be any pre-existing
4597 : : * lockers, as we haven't advertised this vxid via the ProcArray yet.
4598 : : *
4599 : : * Since MyProc->fpLocalTransactionId will normally contain the same data
4600 : : * as MyProc->vxid.lxid, you might wonder if we really need both. The
4601 : : * difference is that MyProc->vxid.lxid is set and cleared unlocked, and
4602 : : * examined by procarray.c, while fpLocalTransactionId is protected by
4603 : : * fpInfoLock and is used only by the locking subsystem. Doing it this
4604 : : * way makes it easier to verify that there are no funny race conditions.
4605 : : *
4606 : : * We don't bother recording this lock in the local lock table, since it's
4607 : : * only ever released at the end of a transaction. Instead,
4608 : : * LockReleaseAll() calls VirtualXactLockTableCleanup().
4609 : : */
4610 : : void
4611 : 670734 : VirtualXactLockTableInsert(VirtualTransactionId vxid)
4612 : : {
4613 : : Assert(VirtualTransactionIdIsValid(vxid));
4614 : :
4615 : 670734 : LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
4616 : :
4617 : : Assert(MyProc->vxid.procNumber == vxid.procNumber);
4618 : : Assert(MyProc->fpLocalTransactionId == InvalidLocalTransactionId);
4619 : : Assert(MyProc->fpVXIDLock == false);
4620 : :
4621 : 670734 : MyProc->fpVXIDLock = true;
4622 : 670734 : MyProc->fpLocalTransactionId = vxid.localTransactionId;
4623 : :
4624 : 670734 : LWLockRelease(&MyProc->fpInfoLock);
4625 : 670734 : }
4626 : :
4627 : : /*
4628 : : * VirtualXactLockTableCleanup
4629 : : *
4630 : : * Check whether a VXID lock has been materialized; if so, release it,
4631 : : * unblocking waiters.
4632 : : */
4633 : : void
4634 : 671296 : VirtualXactLockTableCleanup(void)
4635 : : {
4636 : : bool fastpath;
4637 : : LocalTransactionId lxid;
4638 : :
4639 : : Assert(MyProc->vxid.procNumber != INVALID_PROC_NUMBER);
4640 : :
4641 : : /*
4642 : : * Clean up shared memory state.
4643 : : */
4644 : 671296 : LWLockAcquire(&MyProc->fpInfoLock, LW_EXCLUSIVE);
4645 : :
4646 : 671296 : fastpath = MyProc->fpVXIDLock;
4647 : 671296 : lxid = MyProc->fpLocalTransactionId;
4648 : 671296 : MyProc->fpVXIDLock = false;
4649 : 671296 : MyProc->fpLocalTransactionId = InvalidLocalTransactionId;
4650 : :
4651 : 671296 : LWLockRelease(&MyProc->fpInfoLock);
4652 : :
4653 : : /*
4654 : : * If fpVXIDLock has been cleared without touching fpLocalTransactionId,
4655 : : * that means someone transferred the lock to the main lock table.
4656 : : */
4657 [ + + + + ]: 671296 : if (!fastpath && LocalTransactionIdIsValid(lxid))
4658 : : {
4659 : : VirtualTransactionId vxid;
4660 : : LOCKTAG locktag;
4661 : :
4662 : 290 : vxid.procNumber = MyProcNumber;
4663 : 290 : vxid.localTransactionId = lxid;
4664 : 290 : SET_LOCKTAG_VIRTUALTRANSACTION(locktag, vxid);
4665 : :
4666 : 290 : LockRefindAndRelease(LockMethods[DEFAULT_LOCKMETHOD], MyProc,
4667 : : &locktag, ExclusiveLock, false);
4668 : : }
4669 : 671296 : }
4670 : :
4671 : : /*
4672 : : * XactLockForVirtualXact
4673 : : *
4674 : : * If TransactionIdIsValid(xid), this is essentially XactLockTableWait(xid,
4675 : : * NULL, NULL, XLTW_None) or ConditionalXactLockTableWait(xid). Unlike those
4676 : : * functions, it assumes "xid" is never a subtransaction and that "xid" is
4677 : : * prepared, committed, or aborted.
4678 : : *
4679 : : * If !TransactionIdIsValid(xid), this locks every prepared XID having been
4680 : : * known as "vxid" before its PREPARE TRANSACTION.
4681 : : */
4682 : : static bool
4683 : 311 : XactLockForVirtualXact(VirtualTransactionId vxid,
4684 : : TransactionId xid, bool wait)
4685 : : {
4686 : 311 : bool more = false;
4687 : :
4688 : : /* There is no point to wait for 2PCs if you have no 2PCs. */
4689 [ + + ]: 311 : if (max_prepared_xacts == 0)
4690 : 137 : return true;
4691 : :
4692 : : do
4693 : : {
4694 : : LockAcquireResult lar;
4695 : : LOCKTAG tag;
4696 : :
4697 : : /* Clear state from previous iterations. */
4698 [ - + ]: 174 : if (more)
4699 : : {
4700 : 0 : xid = InvalidTransactionId;
4701 : 0 : more = false;
4702 : : }
4703 : :
4704 : : /* If we have no xid, try to find one. */
4705 [ + + ]: 174 : if (!TransactionIdIsValid(xid))
4706 : 88 : xid = TwoPhaseGetXidByVirtualXID(vxid, &more);
4707 [ + + ]: 174 : if (!TransactionIdIsValid(xid))
4708 : : {
4709 : : Assert(!more);
4710 : 75 : return true;
4711 : : }
4712 : :
4713 : : /* Check or wait for XID completion. */
4714 : 99 : SET_LOCKTAG_TRANSACTION(tag, xid);
4715 : 99 : lar = LockAcquire(&tag, ShareLock, false, !wait);
4716 [ - + ]: 99 : if (lar == LOCKACQUIRE_NOT_AVAIL)
4717 : 0 : return false;
4718 : 99 : LockRelease(&tag, ShareLock, false);
4719 [ - + ]: 99 : } while (more);
4720 : :
4721 : 99 : return true;
4722 : : }
4723 : :
4724 : : /*
4725 : : * VirtualXactLock
4726 : : *
4727 : : * If wait = true, wait as long as the given VXID or any XID acquired by the
4728 : : * same transaction is still running. Then, return true.
4729 : : *
4730 : : * If wait = false, just check whether that VXID or one of those XIDs is still
4731 : : * running, and return true or false.
4732 : : */
4733 : : bool
4734 : 351 : VirtualXactLock(VirtualTransactionId vxid, bool wait)
4735 : : {
4736 : : LOCKTAG tag;
4737 : : PGPROC *proc;
4738 : 351 : TransactionId xid = InvalidTransactionId;
4739 : :
4740 : : Assert(VirtualTransactionIdIsValid(vxid));
4741 : :
4742 [ + + ]: 351 : if (VirtualTransactionIdIsRecoveredPreparedXact(vxid))
4743 : : /* no vxid lock; localTransactionId is a normal, locked XID */
4744 : 1 : return XactLockForVirtualXact(vxid, vxid.localTransactionId, wait);
4745 : :
4746 : 350 : SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid);
4747 : :
4748 : : /*
4749 : : * If a lock table entry must be made, this is the PGPROC on whose behalf
4750 : : * it must be done. Note that the transaction might end or the PGPROC
4751 : : * might be reassigned to a new backend before we get around to examining
4752 : : * it, but it doesn't matter. If we find upon examination that the
4753 : : * relevant lxid is no longer running here, that's enough to prove that
4754 : : * it's no longer running anywhere.
4755 : : */
4756 : 350 : proc = ProcNumberGetProc(vxid.procNumber);
4757 [ + + ]: 350 : if (proc == NULL)
4758 : 3 : return XactLockForVirtualXact(vxid, InvalidTransactionId, wait);
4759 : :
4760 : : /*
4761 : : * We must acquire this lock before checking the procNumber and lxid
4762 : : * against the ones we're waiting for. The target backend will only set
4763 : : * or clear lxid while holding this lock.
4764 : : */
4765 : 347 : LWLockAcquire(&proc->fpInfoLock, LW_EXCLUSIVE);
4766 : :
4767 [ + - ]: 347 : if (proc->vxid.procNumber != vxid.procNumber
4768 [ + + ]: 347 : || proc->fpLocalTransactionId != vxid.localTransactionId)
4769 : : {
4770 : : /* VXID ended */
4771 : 33 : LWLockRelease(&proc->fpInfoLock);
4772 : 33 : return XactLockForVirtualXact(vxid, InvalidTransactionId, wait);
4773 : : }
4774 : :
4775 : : /*
4776 : : * If we aren't asked to wait, there's no need to set up a lock table
4777 : : * entry. The transaction is still in progress, so just return false.
4778 : : */
4779 [ + + ]: 314 : if (!wait)
4780 : : {
4781 : 15 : LWLockRelease(&proc->fpInfoLock);
4782 : 15 : return false;
4783 : : }
4784 : :
4785 : : /*
4786 : : * OK, we're going to need to sleep on the VXID. But first, we must set
4787 : : * up the primary lock table entry, if needed (ie, convert the proc's
4788 : : * fast-path lock on its VXID to a regular lock).
4789 : : */
4790 [ + + ]: 299 : if (proc->fpVXIDLock)
4791 : : {
4792 : : PROCLOCK *proclock;
4793 : : uint32 hashcode;
4794 : : LWLock *partitionLock;
4795 : :
4796 : 290 : hashcode = LockTagHashCode(&tag);
4797 : :
4798 : 290 : partitionLock = LockHashPartitionLock(hashcode);
4799 : 290 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4800 : :
4801 : 290 : proclock = SetupLockInTable(LockMethods[DEFAULT_LOCKMETHOD], proc,
4802 : : &tag, hashcode, ExclusiveLock);
4803 [ - + ]: 290 : if (!proclock)
4804 : : {
4805 : 0 : LWLockRelease(partitionLock);
4806 : 0 : LWLockRelease(&proc->fpInfoLock);
4807 [ # # ]: 0 : ereport(ERROR,
4808 : : (errcode(ERRCODE_OUT_OF_MEMORY),
4809 : : errmsg("out of shared memory"),
4810 : : errhint("You might need to increase \"%s\".", "max_locks_per_transaction")));
4811 : : }
4812 : 290 : GrantLock(proclock->tag.myLock, proclock, ExclusiveLock);
4813 : :
4814 : 290 : LWLockRelease(partitionLock);
4815 : :
4816 : 290 : proc->fpVXIDLock = false;
4817 : : }
4818 : :
4819 : : /*
4820 : : * If the proc has an XID now, we'll avoid a TwoPhaseGetXidByVirtualXID()
4821 : : * search. The proc might have assigned this XID but not yet locked it,
4822 : : * in which case the proc will lock this XID before releasing the VXID.
4823 : : * The fpInfoLock critical section excludes VirtualXactLockTableCleanup(),
4824 : : * so we won't save an XID of a different VXID. It doesn't matter whether
4825 : : * we save this before or after setting up the primary lock table entry.
4826 : : */
4827 : 299 : xid = proc->xid;
4828 : :
4829 : : /* Done with proc->fpLockBits */
4830 : 299 : LWLockRelease(&proc->fpInfoLock);
4831 : :
4832 : : /* Time to wait. */
4833 : 299 : (void) LockAcquire(&tag, ShareLock, false, false);
4834 : :
4835 : 274 : LockRelease(&tag, ShareLock, false);
4836 : 274 : return XactLockForVirtualXact(vxid, xid, wait);
4837 : : }
4838 : :
4839 : : /*
4840 : : * LockWaiterCount
4841 : : *
4842 : : * Find the number of lock requester on this locktag
4843 : : */
4844 : : int
4845 : 95158 : LockWaiterCount(const LOCKTAG *locktag)
4846 : : {
4847 : 95158 : LOCKMETHODID lockmethodid = locktag->locktag_lockmethodid;
4848 : : LOCK *lock;
4849 : : bool found;
4850 : : uint32 hashcode;
4851 : : LWLock *partitionLock;
4852 : 95158 : int waiters = 0;
4853 : :
4854 [ + - - + ]: 95158 : if (lockmethodid <= 0 || lockmethodid >= lengthof(LockMethods))
4855 [ # # ]: 0 : elog(ERROR, "unrecognized lock method: %d", lockmethodid);
4856 : :
4857 : 95158 : hashcode = LockTagHashCode(locktag);
4858 : 95158 : partitionLock = LockHashPartitionLock(hashcode);
4859 : 95158 : LWLockAcquire(partitionLock, LW_EXCLUSIVE);
4860 : :
4861 : 95158 : lock = (LOCK *) hash_search_with_hash_value(LockMethodLockHash,
4862 : : locktag,
4863 : : hashcode,
4864 : : HASH_FIND,
4865 : : &found);
4866 [ + + ]: 95158 : if (found)
4867 : : {
4868 : : Assert(lock != NULL);
4869 : 15 : waiters = lock->nRequested;
4870 : : }
4871 : 95158 : LWLockRelease(partitionLock);
4872 : :
4873 : 95158 : return waiters;
4874 : : }
|
