Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * buf_internals.h
4 : * Internal definitions for buffer manager and the buffer replacement
5 : * strategy.
6 : *
7 : *
8 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
9 : * Portions Copyright (c) 1994, Regents of the University of California
10 : *
11 : * src/include/storage/buf_internals.h
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #ifndef BUFMGR_INTERNALS_H
16 : #define BUFMGR_INTERNALS_H
17 :
18 : #include "pgstat.h"
19 : #include "port/atomics.h"
20 : #include "storage/aio_types.h"
21 : #include "storage/buf.h"
22 : #include "storage/bufmgr.h"
23 : #include "storage/condition_variable.h"
24 : #include "storage/lwlock.h"
25 : #include "storage/procnumber.h"
26 : #include "storage/shmem.h"
27 : #include "storage/smgr.h"
28 : #include "storage/spin.h"
29 : #include "utils/relcache.h"
30 : #include "utils/resowner.h"
31 :
32 : /*
33 : * Buffer state is a single 32-bit variable where following data is combined.
34 : *
35 : * - 18 bits refcount
36 : * - 4 bits usage count
37 : * - 10 bits of flags
38 : *
39 : * Combining these values allows to perform some operations without locking
40 : * the buffer header, by modifying them together with a CAS loop.
41 : *
42 : * The definition of buffer state components is below.
43 : */
44 : #define BUF_REFCOUNT_BITS 18
45 : #define BUF_USAGECOUNT_BITS 4
46 : #define BUF_FLAG_BITS 10
47 :
48 : StaticAssertDecl(BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS + BUF_FLAG_BITS == 32,
49 : "parts of buffer state space need to equal 32");
50 :
51 : #define BUF_REFCOUNT_ONE 1
52 : #define BUF_REFCOUNT_MASK ((1U << BUF_REFCOUNT_BITS) - 1)
53 : #define BUF_USAGECOUNT_MASK (((1U << BUF_USAGECOUNT_BITS) - 1) << (BUF_REFCOUNT_BITS))
54 : #define BUF_USAGECOUNT_ONE (1U << BUF_REFCOUNT_BITS)
55 : #define BUF_USAGECOUNT_SHIFT BUF_REFCOUNT_BITS
56 : #define BUF_FLAG_MASK (((1U << BUF_FLAG_BITS) - 1) << (BUF_REFCOUNT_BITS + BUF_USAGECOUNT_BITS))
57 :
58 : /* Get refcount and usagecount from buffer state */
59 : #define BUF_STATE_GET_REFCOUNT(state) ((state) & BUF_REFCOUNT_MASK)
60 : #define BUF_STATE_GET_USAGECOUNT(state) (((state) & BUF_USAGECOUNT_MASK) >> BUF_USAGECOUNT_SHIFT)
61 :
62 : /*
63 : * Flags for buffer descriptors
64 : *
65 : * Note: BM_TAG_VALID essentially means that there is a buffer hashtable
66 : * entry associated with the buffer's tag.
67 : */
68 : #define BM_LOCKED (1U << 22) /* buffer header is locked */
69 : #define BM_DIRTY (1U << 23) /* data needs writing */
70 : #define BM_VALID (1U << 24) /* data is valid */
71 : #define BM_TAG_VALID (1U << 25) /* tag is assigned */
72 : #define BM_IO_IN_PROGRESS (1U << 26) /* read or write in progress */
73 : #define BM_IO_ERROR (1U << 27) /* previous I/O failed */
74 : #define BM_JUST_DIRTIED (1U << 28) /* dirtied since write started */
75 : #define BM_PIN_COUNT_WAITER (1U << 29) /* have waiter for sole pin */
76 : #define BM_CHECKPOINT_NEEDED (1U << 30) /* must write for checkpoint */
77 : #define BM_PERMANENT (1U << 31) /* permanent buffer (not unlogged,
78 : * or init fork) */
79 : /*
80 : * The maximum allowed value of usage_count represents a tradeoff between
81 : * accuracy and speed of the clock-sweep buffer management algorithm. A
82 : * large value (comparable to NBuffers) would approximate LRU semantics.
83 : * But it can take as many as BM_MAX_USAGE_COUNT+1 complete cycles of the
84 : * clock-sweep hand to find a free buffer, so in practice we don't want the
85 : * value to be very large.
86 : */
87 : #define BM_MAX_USAGE_COUNT 5
88 :
89 : StaticAssertDecl(BM_MAX_USAGE_COUNT < (1 << BUF_USAGECOUNT_BITS),
90 : "BM_MAX_USAGE_COUNT doesn't fit in BUF_USAGECOUNT_BITS bits");
91 : StaticAssertDecl(MAX_BACKENDS_BITS <= BUF_REFCOUNT_BITS,
92 : "MAX_BACKENDS_BITS needs to be <= BUF_REFCOUNT_BITS");
93 :
94 : /*
95 : * Buffer tag identifies which disk block the buffer contains.
96 : *
97 : * Note: the BufferTag data must be sufficient to determine where to write the
98 : * block, without reference to pg_class or pg_tablespace entries. It's
99 : * possible that the backend flushing the buffer doesn't even believe the
100 : * relation is visible yet (its xact may have started before the xact that
101 : * created the rel). The storage manager must be able to cope anyway.
102 : *
103 : * Note: if there's any pad bytes in the struct, InitBufferTag will have
104 : * to be fixed to zero them, since this struct is used as a hash key.
105 : */
106 : typedef struct buftag
107 : {
108 : Oid spcOid; /* tablespace oid */
109 : Oid dbOid; /* database oid */
110 : RelFileNumber relNumber; /* relation file number */
111 : ForkNumber forkNum; /* fork number */
112 : BlockNumber blockNum; /* blknum relative to begin of reln */
113 : } BufferTag;
114 :
115 : static inline RelFileNumber
116 304594710 : BufTagGetRelNumber(const BufferTag *tag)
117 : {
118 304594710 : return tag->relNumber;
119 : }
120 :
121 : static inline ForkNumber
122 43722948 : BufTagGetForkNum(const BufferTag *tag)
123 : {
124 43722948 : return tag->forkNum;
125 : }
126 :
127 : static inline void
128 146020752 : BufTagSetRelForkDetails(BufferTag *tag, RelFileNumber relnumber,
129 : ForkNumber forknum)
130 : {
131 146020752 : tag->relNumber = relnumber;
132 146020752 : tag->forkNum = forknum;
133 146020752 : }
134 :
135 : static inline RelFileLocator
136 35113680 : BufTagGetRelFileLocator(const BufferTag *tag)
137 : {
138 : RelFileLocator rlocator;
139 :
140 35113680 : rlocator.spcOid = tag->spcOid;
141 35113680 : rlocator.dbOid = tag->dbOid;
142 35113680 : rlocator.relNumber = BufTagGetRelNumber(tag);
143 :
144 35113680 : return rlocator;
145 : }
146 :
147 : static inline void
148 23193434 : ClearBufferTag(BufferTag *tag)
149 : {
150 23193434 : tag->spcOid = InvalidOid;
151 23193434 : tag->dbOid = InvalidOid;
152 23193434 : BufTagSetRelForkDetails(tag, InvalidRelFileNumber, InvalidForkNumber);
153 23193434 : tag->blockNum = InvalidBlockNumber;
154 23193434 : }
155 :
156 : static inline void
157 122827318 : InitBufferTag(BufferTag *tag, const RelFileLocator *rlocator,
158 : ForkNumber forkNum, BlockNumber blockNum)
159 : {
160 122827318 : tag->spcOid = rlocator->spcOid;
161 122827318 : tag->dbOid = rlocator->dbOid;
162 122827318 : BufTagSetRelForkDetails(tag, rlocator->relNumber, forkNum);
163 122827318 : tag->blockNum = blockNum;
164 122827318 : }
165 :
166 : static inline bool
167 249122 : BufferTagsEqual(const BufferTag *tag1, const BufferTag *tag2)
168 : {
169 498242 : return (tag1->spcOid == tag2->spcOid) &&
170 249120 : (tag1->dbOid == tag2->dbOid) &&
171 249120 : (tag1->relNumber == tag2->relNumber) &&
172 747278 : (tag1->blockNum == tag2->blockNum) &&
173 249036 : (tag1->forkNum == tag2->forkNum);
174 : }
175 :
176 : static inline bool
177 818566096 : BufTagMatchesRelFileLocator(const BufferTag *tag,
178 : const RelFileLocator *rlocator)
179 : {
180 1154099606 : return (tag->spcOid == rlocator->spcOid) &&
181 1087391004 : (tag->dbOid == rlocator->dbOid) &&
182 268824908 : (BufTagGetRelNumber(tag) == rlocator->relNumber);
183 : }
184 :
185 :
186 : /*
187 : * The shared buffer mapping table is partitioned to reduce contention.
188 : * To determine which partition lock a given tag requires, compute the tag's
189 : * hash code with BufTableHashCode(), then apply BufMappingPartitionLock().
190 : * NB: NUM_BUFFER_PARTITIONS must be a power of 2!
191 : */
192 : static inline uint32
193 122855572 : BufTableHashPartition(uint32 hashcode)
194 : {
195 122855572 : return hashcode % NUM_BUFFER_PARTITIONS;
196 : }
197 :
198 : static inline LWLock *
199 122855572 : BufMappingPartitionLock(uint32 hashcode)
200 : {
201 122855572 : return &MainLWLockArray[BUFFER_MAPPING_LWLOCK_OFFSET +
202 122855572 : BufTableHashPartition(hashcode)].lock;
203 : }
204 :
205 : static inline LWLock *
206 : BufMappingPartitionLockByIndex(uint32 index)
207 : {
208 : return &MainLWLockArray[BUFFER_MAPPING_LWLOCK_OFFSET + index].lock;
209 : }
210 :
211 : /*
212 : * BufferDesc -- shared descriptor/state data for a single shared buffer.
213 : *
214 : * The state of the buffer is controlled by the, drumroll, state variable. It
215 : * only may be modified using atomic operations. The state variable combines
216 : * various flags, the buffer's refcount and usage count. See comment above
217 : * BUF_REFCOUNT_BITS for details about the division. This layout allow us to
218 : * do some operations in a single atomic operation, without actually acquiring
219 : * and releasing the spinlock; for instance, increasing or decreasing the
220 : * refcount.
221 : *
222 : * One of the aforementioned flags is BM_LOCKED, used to implement the buffer
223 : * header lock. See the following paragraphs, as well as the documentation for
224 : * individual fields, for more details.
225 : *
226 : * The identity of the buffer (BufferDesc.tag) can only be changed by the
227 : * backend holding the buffer header lock.
228 : *
229 : * If the lock is held by another backend, neither additional buffer pins may
230 : * be established (we would like to relax this eventually), nor can flags be
231 : * set/cleared. These operations either need to acquire the buffer header
232 : * spinlock, or need to use a CAS loop, waiting for the lock to be released if
233 : * it is held. However, existing buffer pins may be released while the buffer
234 : * header spinlock is held, using an atomic subtraction.
235 : *
236 : * The LWLock can take care of itself. The buffer header lock is *not* used
237 : * to control access to the data in the buffer!
238 : *
239 : * If we have the buffer pinned, its tag can't change underneath us, so we can
240 : * examine the tag without locking the buffer header. Also, in places we do
241 : * one-time reads of the flags without bothering to lock the buffer header;
242 : * this is generally for situations where we don't expect the flag bit being
243 : * tested to be changing.
244 : *
245 : * We can't physically remove items from a disk page if another backend has
246 : * the buffer pinned. Hence, a backend may need to wait for all other pins
247 : * to go away. This is signaled by storing its own pgprocno into
248 : * wait_backend_pgprocno and setting flag bit BM_PIN_COUNT_WAITER. At present,
249 : * there can be only one such waiter per buffer.
250 : *
251 : * We use this same struct for local buffer headers, but the locks are not
252 : * used and not all of the flag bits are useful either. To avoid unnecessary
253 : * overhead, manipulations of the state field should be done without actual
254 : * atomic operations (i.e. only pg_atomic_read_u32() and
255 : * pg_atomic_unlocked_write_u32()).
256 : *
257 : * Be careful to avoid increasing the size of the struct when adding or
258 : * reordering members. Keeping it below 64 bytes (the most common CPU
259 : * cache line size) is fairly important for performance.
260 : *
261 : * Per-buffer I/O condition variables are currently kept outside this struct in
262 : * a separate array. They could be moved in here and still fit within that
263 : * limit on common systems, but for now that is not done.
264 : */
265 : typedef struct BufferDesc
266 : {
267 : /*
268 : * ID of page contained in buffer. The buffer header spinlock needs to be
269 : * held to modify this field.
270 : */
271 : BufferTag tag;
272 :
273 : /*
274 : * Buffer's index number (from 0). The field never changes after
275 : * initialization, so does not need locking.
276 : */
277 : int buf_id;
278 :
279 : /*
280 : * State of the buffer, containing flags, refcount and usagecount. See
281 : * BUF_* and BM_* defines at the top of this file.
282 : */
283 : pg_atomic_uint32 state;
284 :
285 : /*
286 : * Backend of pin-count waiter. The buffer header spinlock needs to be
287 : * held to modify this field.
288 : */
289 : int wait_backend_pgprocno;
290 :
291 : PgAioWaitRef io_wref; /* set iff AIO is in progress */
292 : LWLock content_lock; /* to lock access to buffer contents */
293 : } BufferDesc;
294 :
295 : /*
296 : * Concurrent access to buffer headers has proven to be more efficient if
297 : * they're cache line aligned. So we force the start of the BufferDescriptors
298 : * array to be on a cache line boundary and force the elements to be cache
299 : * line sized.
300 : *
301 : * XXX: As this is primarily matters in highly concurrent workloads which
302 : * probably all are 64bit these days, and the space wastage would be a bit
303 : * more noticeable on 32bit systems, we don't force the stride to be cache
304 : * line sized on those. If somebody does actual performance testing, we can
305 : * reevaluate.
306 : *
307 : * Note that local buffer descriptors aren't forced to be aligned - as there's
308 : * no concurrent access to those it's unlikely to be beneficial.
309 : *
310 : * We use a 64-byte cache line size here, because that's the most common
311 : * size. Making it bigger would be a waste of memory. Even if running on a
312 : * platform with either 32 or 128 byte line sizes, it's good to align to
313 : * boundaries and avoid false sharing.
314 : */
315 : #define BUFFERDESC_PAD_TO_SIZE (SIZEOF_VOID_P == 8 ? 64 : 1)
316 :
317 : typedef union BufferDescPadded
318 : {
319 : BufferDesc bufferdesc;
320 : char pad[BUFFERDESC_PAD_TO_SIZE];
321 : } BufferDescPadded;
322 :
323 : /*
324 : * The PendingWriteback & WritebackContext structure are used to keep
325 : * information about pending flush requests to be issued to the OS.
326 : */
327 : typedef struct PendingWriteback
328 : {
329 : /* could store different types of pending flushes here */
330 : BufferTag tag;
331 : } PendingWriteback;
332 :
333 : /* struct forward declared in bufmgr.h */
334 : typedef struct WritebackContext
335 : {
336 : /* pointer to the max number of writeback requests to coalesce */
337 : int *max_pending;
338 :
339 : /* current number of pending writeback requests */
340 : int nr_pending;
341 :
342 : /* pending requests */
343 : PendingWriteback pending_writebacks[WRITEBACK_MAX_PENDING_FLUSHES];
344 : } WritebackContext;
345 :
346 : /* in buf_init.c */
347 : extern PGDLLIMPORT BufferDescPadded *BufferDescriptors;
348 : extern PGDLLIMPORT ConditionVariableMinimallyPadded *BufferIOCVArray;
349 : extern PGDLLIMPORT WritebackContext BackendWritebackContext;
350 :
351 : /* in localbuf.c */
352 : extern PGDLLIMPORT BufferDesc *LocalBufferDescriptors;
353 :
354 :
355 : static inline BufferDesc *
356 1161922162 : GetBufferDescriptor(uint32 id)
357 : {
358 1161922162 : return &(BufferDescriptors[id]).bufferdesc;
359 : }
360 :
361 : static inline BufferDesc *
362 20059934 : GetLocalBufferDescriptor(uint32 id)
363 : {
364 20059934 : return &LocalBufferDescriptors[id];
365 : }
366 :
367 : static inline Buffer
368 546413920 : BufferDescriptorGetBuffer(const BufferDesc *bdesc)
369 : {
370 546413920 : return (Buffer) (bdesc->buf_id + 1);
371 : }
372 :
373 : static inline ConditionVariable *
374 25270684 : BufferDescriptorGetIOCV(const BufferDesc *bdesc)
375 : {
376 25270684 : return &(BufferIOCVArray[bdesc->buf_id]).cv;
377 : }
378 :
379 : static inline LWLock *
380 348010864 : BufferDescriptorGetContentLock(const BufferDesc *bdesc)
381 : {
382 348010864 : return (LWLock *) (&bdesc->content_lock);
383 : }
384 :
385 : /*
386 : * Functions for acquiring/releasing a shared buffer header's spinlock. Do
387 : * not apply these to local buffers!
388 : */
389 : extern uint32 LockBufHdr(BufferDesc *desc);
390 :
391 : /*
392 : * Unlock the buffer header.
393 : *
394 : * This can only be used if the caller did not modify BufferDesc.state. To
395 : * set/unset flag bits or change the refcount use UnlockBufHdrExt().
396 : */
397 : static inline void
398 18653908 : UnlockBufHdr(BufferDesc *desc)
399 : {
400 : Assert(pg_atomic_read_u32(&desc->state) & BM_LOCKED);
401 :
402 18653908 : pg_atomic_fetch_sub_u32(&desc->state, BM_LOCKED);
403 18653908 : }
404 :
405 : /*
406 : * Unlock the buffer header, while atomically adding the flags in set_bits,
407 : * unsetting the ones in unset_bits and changing the refcount by
408 : * refcount_change.
409 : *
410 : * Note that this approach would not work for usagecount, since we need to cap
411 : * the usagecount at BM_MAX_USAGE_COUNT.
412 : */
413 : static inline uint32
414 45010778 : UnlockBufHdrExt(BufferDesc *desc, uint32 old_buf_state,
415 : uint32 set_bits, uint32 unset_bits,
416 : int refcount_change)
417 : {
418 : for (;;)
419 4 : {
420 45010782 : uint32 buf_state = old_buf_state;
421 :
422 : Assert(buf_state & BM_LOCKED);
423 :
424 45010782 : buf_state |= set_bits;
425 45010782 : buf_state &= ~unset_bits;
426 45010782 : buf_state &= ~BM_LOCKED;
427 :
428 45010782 : if (refcount_change != 0)
429 6038770 : buf_state += BUF_REFCOUNT_ONE * refcount_change;
430 :
431 45010782 : if (pg_atomic_compare_exchange_u32(&desc->state, &old_buf_state,
432 : buf_state))
433 : {
434 45010778 : return old_buf_state;
435 : }
436 : }
437 : }
438 :
439 : extern uint32 WaitBufHdrUnlocked(BufferDesc *buf);
440 :
441 : /* in bufmgr.c */
442 :
443 : /*
444 : * Structure to sort buffers per file on checkpoints.
445 : *
446 : * This structure is allocated per buffer in shared memory, so it should be
447 : * kept as small as possible.
448 : */
449 : typedef struct CkptSortItem
450 : {
451 : Oid tsId;
452 : RelFileNumber relNumber;
453 : ForkNumber forkNum;
454 : BlockNumber blockNum;
455 : int buf_id;
456 : } CkptSortItem;
457 :
458 : extern PGDLLIMPORT CkptSortItem *CkptBufferIds;
459 :
460 : /* ResourceOwner callbacks to hold buffer I/Os and pins */
461 : extern PGDLLIMPORT const ResourceOwnerDesc buffer_io_resowner_desc;
462 : extern PGDLLIMPORT const ResourceOwnerDesc buffer_pin_resowner_desc;
463 :
464 : /* Convenience wrappers over ResourceOwnerRemember/Forget */
465 : static inline void
466 146285548 : ResourceOwnerRememberBuffer(ResourceOwner owner, Buffer buffer)
467 : {
468 146285548 : ResourceOwnerRemember(owner, Int32GetDatum(buffer), &buffer_pin_resowner_desc);
469 146285548 : }
470 : static inline void
471 146270350 : ResourceOwnerForgetBuffer(ResourceOwner owner, Buffer buffer)
472 : {
473 146270350 : ResourceOwnerForget(owner, Int32GetDatum(buffer), &buffer_pin_resowner_desc);
474 146270350 : }
475 : static inline void
476 4990058 : ResourceOwnerRememberBufferIO(ResourceOwner owner, Buffer buffer)
477 : {
478 4990058 : ResourceOwnerRemember(owner, Int32GetDatum(buffer), &buffer_io_resowner_desc);
479 4990058 : }
480 : static inline void
481 4990028 : ResourceOwnerForgetBufferIO(ResourceOwner owner, Buffer buffer)
482 : {
483 4990028 : ResourceOwnerForget(owner, Int32GetDatum(buffer), &buffer_io_resowner_desc);
484 4990028 : }
485 :
486 : /*
487 : * Internal buffer management routines
488 : */
489 : /* bufmgr.c */
490 : extern void WritebackContextInit(WritebackContext *context, int *max_pending);
491 : extern void IssuePendingWritebacks(WritebackContext *wb_context, IOContext io_context);
492 : extern void ScheduleBufferTagForWriteback(WritebackContext *wb_context,
493 : IOContext io_context, BufferTag *tag);
494 :
495 : extern void TrackNewBufferPin(Buffer buf);
496 :
497 : /* solely to make it easier to write tests */
498 : extern bool StartBufferIO(BufferDesc *buf, bool forInput, bool nowait);
499 : extern void TerminateBufferIO(BufferDesc *buf, bool clear_dirty, uint32 set_flag_bits,
500 : bool forget_owner, bool release_aio);
501 :
502 :
503 : /* freelist.c */
504 : extern IOContext IOContextForStrategy(BufferAccessStrategy strategy);
505 : extern BufferDesc *StrategyGetBuffer(BufferAccessStrategy strategy,
506 : uint32 *buf_state, bool *from_ring);
507 : extern bool StrategyRejectBuffer(BufferAccessStrategy strategy,
508 : BufferDesc *buf, bool from_ring);
509 :
510 : extern int StrategySyncStart(uint32 *complete_passes, uint32 *num_buf_alloc);
511 : extern void StrategyNotifyBgWriter(int bgwprocno);
512 :
513 : extern Size StrategyShmemSize(void);
514 : extern void StrategyInitialize(bool init);
515 :
516 : /* buf_table.c */
517 : extern Size BufTableShmemSize(int size);
518 : extern void InitBufTable(int size);
519 : extern uint32 BufTableHashCode(BufferTag *tagPtr);
520 : extern int BufTableLookup(BufferTag *tagPtr, uint32 hashcode);
521 : extern int BufTableInsert(BufferTag *tagPtr, uint32 hashcode, int buf_id);
522 : extern void BufTableDelete(BufferTag *tagPtr, uint32 hashcode);
523 :
524 : /* localbuf.c */
525 : extern bool PinLocalBuffer(BufferDesc *buf_hdr, bool adjust_usagecount);
526 : extern void UnpinLocalBuffer(Buffer buffer);
527 : extern void UnpinLocalBufferNoOwner(Buffer buffer);
528 : extern PrefetchBufferResult PrefetchLocalBuffer(SMgrRelation smgr,
529 : ForkNumber forkNum,
530 : BlockNumber blockNum);
531 : extern BufferDesc *LocalBufferAlloc(SMgrRelation smgr, ForkNumber forkNum,
532 : BlockNumber blockNum, bool *foundPtr);
533 : extern BlockNumber ExtendBufferedRelLocal(BufferManagerRelation bmr,
534 : ForkNumber fork,
535 : uint32 flags,
536 : uint32 extend_by,
537 : BlockNumber extend_upto,
538 : Buffer *buffers,
539 : uint32 *extended_by);
540 : extern void MarkLocalBufferDirty(Buffer buffer);
541 : extern void TerminateLocalBufferIO(BufferDesc *bufHdr, bool clear_dirty,
542 : uint32 set_flag_bits, bool release_aio);
543 : extern bool StartLocalBufferIO(BufferDesc *bufHdr, bool forInput, bool nowait);
544 : extern void FlushLocalBuffer(BufferDesc *bufHdr, SMgrRelation reln);
545 : extern void InvalidateLocalBuffer(BufferDesc *bufHdr, bool check_unreferenced);
546 : extern void DropRelationLocalBuffers(RelFileLocator rlocator,
547 : ForkNumber *forkNum, int nforks,
548 : BlockNumber *firstDelBlock);
549 : extern void DropRelationAllLocalBuffers(RelFileLocator rlocator);
550 : extern void AtEOXact_LocalBuffers(bool isCommit);
551 :
552 : #endif /* BUFMGR_INTERNALS_H */
|
