Line data Source code
1 : /* ----------
2 : * pgstat_internal.h
3 : *
4 : * Definitions for the PostgreSQL cumulative statistics system that should
5 : * only be needed by files implementing statistics support (rather than ones
6 : * reporting / querying stats).
7 : *
8 : * Copyright (c) 2001-2024, PostgreSQL Global Development Group
9 : *
10 : * src/include/utils/pgstat_internal.h
11 : * ----------
12 : */
13 : #ifndef PGSTAT_INTERNAL_H
14 : #define PGSTAT_INTERNAL_H
15 :
16 :
17 : #include "common/hashfn_unstable.h"
18 : #include "lib/dshash.h"
19 : #include "lib/ilist.h"
20 : #include "pgstat.h"
21 : #include "storage/lwlock.h"
22 : #include "utils/dsa.h"
23 :
24 :
25 : /*
26 : * Types related to shared memory storage of statistics.
27 : *
28 : * Per-object statistics are stored in the "shared stats" hashtable. That
29 : * table's entries (PgStatShared_HashEntry) contain a pointer to the actual stats
30 : * data for the object (the size of the stats data varies depending on the
31 : * kind of stats). The table is keyed by PgStat_HashKey.
32 : *
33 : * Once a backend has a reference to a shared stats entry, it increments the
34 : * entry's refcount. Even after stats data is dropped (e.g., due to a DROP
35 : * TABLE), the entry itself can only be deleted once all references have been
36 : * released.
37 : *
38 : * These refcounts, in combination with a backend local hashtable
39 : * (pgStatEntryRefHash, with entries pointing to PgStat_EntryRef) in front of
40 : * the shared hash table, mean that most stats work can happen without
41 : * touching the shared hash table, reducing contention.
42 : *
43 : * Once there are pending stats updates for a table PgStat_EntryRef->pending
44 : * is allocated to contain a working space for as-of-yet-unapplied stats
45 : * updates. Once the stats are flushed, PgStat_EntryRef->pending is freed.
46 : *
47 : * Each stat kind in the shared hash table has a fixed member
48 : * PgStatShared_Common as the first element.
49 : */
50 :
51 : /* struct for shared statistics hash entry key. */
52 : typedef struct PgStat_HashKey
53 : {
54 : PgStat_Kind kind; /* statistics entry kind */
55 : Oid dboid; /* database ID. InvalidOid for shared objects. */
56 : uint64 objid; /* object ID (table, function, etc.), or
57 : * identifier. */
58 : } PgStat_HashKey;
59 :
60 : /*
61 : * Shared statistics hash entry. Doesn't itself contain any stats, but points
62 : * to them (with ->body). That allows the stats entries themselves to be of
63 : * variable size.
64 : */
65 : typedef struct PgStatShared_HashEntry
66 : {
67 : PgStat_HashKey key; /* hash key */
68 :
69 : /*
70 : * If dropped is set, backends need to release their references so that
71 : * the memory for the entry can be freed. No new references may be made
72 : * once marked as dropped.
73 : */
74 : bool dropped;
75 :
76 : /*
77 : * Refcount managing lifetime of the entry itself (as opposed to the
78 : * dshash entry pointing to it). The stats lifetime has to be separate
79 : * from the hash table entry lifetime because we allow backends to point
80 : * to a stats entry without holding a hash table lock (and some other
81 : * reasons).
82 : *
83 : * As long as the entry is not dropped, 1 is added to the refcount
84 : * representing that the entry should not be dropped. In addition each
85 : * backend that has a reference to the entry needs to increment the
86 : * refcount as long as it does.
87 : *
88 : * May only be incremented / decremented while holding at least a shared
89 : * lock on the dshash partition containing the entry. It needs to be an
90 : * atomic variable because multiple backends can increment the refcount
91 : * with just a shared lock.
92 : *
93 : * When the refcount reaches 0 the entry needs to be freed.
94 : */
95 : pg_atomic_uint32 refcount;
96 :
97 : /*
98 : * Counter tracking the number of times the entry has been reused.
99 : *
100 : * Set to 0 when the entry is created, and incremented by one each time
101 : * the shared entry is reinitialized with pgstat_reinit_entry().
102 : *
103 : * May only be incremented / decremented while holding at least a shared
104 : * lock on the dshash partition containing the entry. Like refcount, it
105 : * needs to be an atomic variable because multiple backends can increment
106 : * the generation with just a shared lock.
107 : */
108 : pg_atomic_uint32 generation;
109 :
110 : /*
111 : * Pointer to shared stats. The stats entry always starts with
112 : * PgStatShared_Common, embedded in a larger struct containing the
113 : * PgStat_Kind specific stats fields.
114 : */
115 : dsa_pointer body;
116 : } PgStatShared_HashEntry;
117 :
118 : /*
119 : * Common header struct for PgStatShared_*.
120 : */
121 : typedef struct PgStatShared_Common
122 : {
123 : uint32 magic; /* just a validity cross-check */
124 : /* lock protecting stats contents (i.e. data following the header) */
125 : LWLock lock;
126 : } PgStatShared_Common;
127 :
128 : /*
129 : * A backend local reference to a shared stats entry. As long as at least one
130 : * such reference exists, the shared stats entry will not be released.
131 : *
132 : * If there are pending stats update to the shared stats, these are stored in
133 : * ->pending.
134 : */
135 : typedef struct PgStat_EntryRef
136 : {
137 : /*
138 : * Pointer to the PgStatShared_HashEntry entry in the shared stats
139 : * hashtable.
140 : */
141 : PgStatShared_HashEntry *shared_entry;
142 :
143 : /*
144 : * Pointer to the stats data (i.e. PgStatShared_HashEntry->body), resolved
145 : * as a local pointer, to avoid repeated dsa_get_address() calls.
146 : */
147 : PgStatShared_Common *shared_stats;
148 :
149 : /*
150 : * Copy of PgStatShared_HashEntry->generation, keeping locally track of
151 : * the shared stats entry "generation" retrieved (number of times reused).
152 : */
153 : uint32 generation;
154 :
155 : /*
156 : * Pending statistics data that will need to be flushed to shared memory
157 : * stats eventually. Each stats kind utilizing pending data defines what
158 : * format its pending data has and needs to provide a
159 : * PgStat_KindInfo->flush_pending_cb callback to merge pending into shared
160 : * stats.
161 : */
162 : void *pending;
163 : dlist_node pending_node; /* membership in pgStatPending list */
164 : } PgStat_EntryRef;
165 :
166 :
167 : /*
168 : * Some stats changes are transactional. To maintain those, a stack of
169 : * PgStat_SubXactStatus entries is maintained, which contain data pertaining
170 : * to the current transaction and its active subtransactions.
171 : */
172 : typedef struct PgStat_SubXactStatus
173 : {
174 : int nest_level; /* subtransaction nest level */
175 :
176 : struct PgStat_SubXactStatus *prev; /* higher-level subxact if any */
177 :
178 : /*
179 : * Statistics for transactionally dropped objects need to be
180 : * transactionally dropped as well. Collect the stats dropped in the
181 : * current (sub-)transaction and only execute the stats drop when we know
182 : * if the transaction commits/aborts. To handle replicas and crashes,
183 : * stats drops are included in commit / abort records.
184 : */
185 : dclist_head pending_drops;
186 :
187 : /*
188 : * Tuple insertion/deletion counts for an open transaction can't be
189 : * propagated into PgStat_TableStatus counters until we know if it is
190 : * going to commit or abort. Hence, we keep these counts in per-subxact
191 : * structs that live in TopTransactionContext. This data structure is
192 : * designed on the assumption that subxacts won't usually modify very many
193 : * tables.
194 : */
195 : PgStat_TableXactStatus *first; /* head of list for this subxact */
196 : } PgStat_SubXactStatus;
197 :
198 :
199 : /*
200 : * Metadata for a specific kind of statistics.
201 : */
202 : typedef struct PgStat_KindInfo
203 : {
204 : /*
205 : * Do a fixed number of stats objects exist for this kind of stats (e.g.
206 : * bgwriter stats) or not (e.g. tables).
207 : */
208 : bool fixed_amount:1;
209 :
210 : /*
211 : * Can stats of this kind be accessed from another database? Determines
212 : * whether a stats object gets included in stats snapshots.
213 : */
214 : bool accessed_across_databases:1;
215 :
216 : /*
217 : * The size of an entry in the shared stats hash table (pointed to by
218 : * PgStatShared_HashEntry->body). For fixed-numbered statistics, this is
219 : * the size of an entry in PgStat_ShmemControl->custom_data.
220 : */
221 : uint32 shared_size;
222 :
223 : /*
224 : * The offset of the statistics struct in the cached statistics snapshot
225 : * PgStat_Snapshot, for fixed-numbered statistics.
226 : */
227 : uint32 snapshot_ctl_off;
228 :
229 : /*
230 : * The offset of the statistics struct in the containing shared memory
231 : * control structure PgStat_ShmemControl, for fixed-numbered statistics.
232 : */
233 : uint32 shared_ctl_off;
234 :
235 : /*
236 : * The offset/size of statistics inside the shared stats entry. Used when
237 : * [de-]serializing statistics to / from disk respectively. Separate from
238 : * shared_size because [de-]serialization may not include in-memory state
239 : * like lwlocks.
240 : */
241 : uint32 shared_data_off;
242 : uint32 shared_data_len;
243 :
244 : /*
245 : * The size of the pending data for this kind. E.g. how large
246 : * PgStat_EntryRef->pending is. Used for allocations.
247 : *
248 : * 0 signals that an entry of this kind should never have a pending entry.
249 : */
250 : uint32 pending_size;
251 :
252 : /*
253 : * Perform custom actions when initializing a backend (standalone or under
254 : * postmaster). Optional.
255 : */
256 : void (*init_backend_cb) (void);
257 :
258 : /*
259 : * For variable-numbered stats: flush pending stats. Required if pending
260 : * data is used. See flush_fixed_cb for fixed-numbered stats.
261 : */
262 : bool (*flush_pending_cb) (PgStat_EntryRef *sr, bool nowait);
263 :
264 : /*
265 : * For variable-numbered stats: delete pending stats. Optional.
266 : */
267 : void (*delete_pending_cb) (PgStat_EntryRef *sr);
268 :
269 : /*
270 : * For variable-numbered stats: reset the reset timestamp. Optional.
271 : */
272 : void (*reset_timestamp_cb) (PgStatShared_Common *header, TimestampTz ts);
273 :
274 : /*
275 : * For variable-numbered stats. Optional.
276 : */
277 : void (*to_serialized_name) (const PgStat_HashKey *key,
278 : const PgStatShared_Common *header, NameData *name);
279 : bool (*from_serialized_name) (const NameData *name, PgStat_HashKey *key);
280 :
281 : /*
282 : * For fixed-numbered statistics: Initialize shared memory state.
283 : *
284 : * "stats" is the pointer to the allocated shared memory area.
285 : */
286 : void (*init_shmem_cb) (void *stats);
287 :
288 : /*
289 : * For fixed-numbered statistics: Flush pending stats. Returns true if
290 : * some of the stats could not be flushed, due to lock contention for
291 : * example. Optional.
292 : */
293 : bool (*flush_fixed_cb) (bool nowait);
294 :
295 : /*
296 : * For fixed-numbered statistics: Check for pending stats in need of
297 : * flush. Returns true if there are any stats pending for flush. Optional.
298 : */
299 : bool (*have_fixed_pending_cb) (void);
300 :
301 : /*
302 : * For fixed-numbered statistics: Reset All.
303 : */
304 : void (*reset_all_cb) (TimestampTz ts);
305 :
306 : /*
307 : * For fixed-numbered statistics: Build snapshot for entry
308 : */
309 : void (*snapshot_cb) (void);
310 :
311 : /* name of the kind of stats */
312 : const char *const name;
313 : } PgStat_KindInfo;
314 :
315 :
316 : /*
317 : * List of SLRU names that we keep stats for. There is no central registry of
318 : * SLRUs, so we use this fixed list instead. The "other" entry is used for
319 : * all SLRUs without an explicit entry (e.g. SLRUs in extensions).
320 : *
321 : * This is only defined here so that SLRU_NUM_ELEMENTS is known for later type
322 : * definitions.
323 : */
324 : static const char *const slru_names[] = {
325 : "commit_timestamp",
326 : "multixact_member",
327 : "multixact_offset",
328 : "notify",
329 : "serializable",
330 : "subtransaction",
331 : "transaction",
332 : "other" /* has to be last */
333 : };
334 :
335 : #define SLRU_NUM_ELEMENTS lengthof(slru_names)
336 :
337 :
338 : /* ----------
339 : * Types and definitions for different kinds of fixed-amount stats.
340 : *
341 : * Single-writer stats use the changecount mechanism to achieve low-overhead
342 : * writes - they're obviously more performance critical than reads. Check the
343 : * definition of struct PgBackendStatus for some explanation of the
344 : * changecount mechanism.
345 : *
346 : * Because the obvious implementation of resetting single-writer stats isn't
347 : * compatible with that (another backend needs to write), we don't scribble on
348 : * shared stats while resetting. Instead, just record the current counter
349 : * values in a copy of the stats data, which is protected by ->lock. See
350 : * pgstat_fetch_stat_(archiver|bgwriter|checkpointer) for the reader side.
351 : *
352 : * The only exception to that is the stat_reset_timestamp in these structs,
353 : * which is protected by ->lock, because it has to be written by another
354 : * backend while resetting.
355 : * ----------
356 : */
357 :
358 : typedef struct PgStatShared_Archiver
359 : {
360 : /* lock protects ->reset_offset as well as stats->stat_reset_timestamp */
361 : LWLock lock;
362 : uint32 changecount;
363 : PgStat_ArchiverStats stats;
364 : PgStat_ArchiverStats reset_offset;
365 : } PgStatShared_Archiver;
366 :
367 : typedef struct PgStatShared_BgWriter
368 : {
369 : /* lock protects ->reset_offset as well as stats->stat_reset_timestamp */
370 : LWLock lock;
371 : uint32 changecount;
372 : PgStat_BgWriterStats stats;
373 : PgStat_BgWriterStats reset_offset;
374 : } PgStatShared_BgWriter;
375 :
376 : typedef struct PgStatShared_Checkpointer
377 : {
378 : /* lock protects ->reset_offset as well as stats->stat_reset_timestamp */
379 : LWLock lock;
380 : uint32 changecount;
381 : PgStat_CheckpointerStats stats;
382 : PgStat_CheckpointerStats reset_offset;
383 : } PgStatShared_Checkpointer;
384 :
385 : /* Shared-memory ready PgStat_IO */
386 : typedef struct PgStatShared_IO
387 : {
388 : /*
389 : * locks[i] protects stats.stats[i]. locks[0] also protects
390 : * stats.stat_reset_timestamp.
391 : */
392 : LWLock locks[BACKEND_NUM_TYPES];
393 : PgStat_IO stats;
394 : } PgStatShared_IO;
395 :
396 : typedef struct PgStatShared_SLRU
397 : {
398 : /* lock protects ->stats */
399 : LWLock lock;
400 : PgStat_SLRUStats stats[SLRU_NUM_ELEMENTS];
401 : } PgStatShared_SLRU;
402 :
403 : typedef struct PgStatShared_Wal
404 : {
405 : /* lock protects ->stats */
406 : LWLock lock;
407 : PgStat_WalStats stats;
408 : } PgStatShared_Wal;
409 :
410 :
411 :
412 : /* ----------
413 : * Types and definitions for different kinds of variable-amount stats.
414 : *
415 : * Each struct has to start with PgStatShared_Common, containing information
416 : * common across the different types of stats. Kind-specific data follows.
417 : * ----------
418 : */
419 :
420 : typedef struct PgStatShared_Database
421 : {
422 : PgStatShared_Common header;
423 : PgStat_StatDBEntry stats;
424 : } PgStatShared_Database;
425 :
426 : typedef struct PgStatShared_Relation
427 : {
428 : PgStatShared_Common header;
429 : PgStat_StatTabEntry stats;
430 : } PgStatShared_Relation;
431 :
432 : typedef struct PgStatShared_Function
433 : {
434 : PgStatShared_Common header;
435 : PgStat_StatFuncEntry stats;
436 : } PgStatShared_Function;
437 :
438 : typedef struct PgStatShared_Subscription
439 : {
440 : PgStatShared_Common header;
441 : PgStat_StatSubEntry stats;
442 : } PgStatShared_Subscription;
443 :
444 : typedef struct PgStatShared_ReplSlot
445 : {
446 : PgStatShared_Common header;
447 : PgStat_StatReplSlotEntry stats;
448 : } PgStatShared_ReplSlot;
449 :
450 :
451 : /*
452 : * Central shared memory entry for the cumulative stats system.
453 : *
454 : * Fixed amount stats, the dynamic shared memory hash table for
455 : * non-fixed-amount stats, as well as remaining bits and pieces are all
456 : * reached from here.
457 : */
458 : typedef struct PgStat_ShmemControl
459 : {
460 : void *raw_dsa_area;
461 :
462 : /*
463 : * Stats for variable-numbered objects are kept in this shared hash table.
464 : * See comment above PgStat_Kind for details.
465 : */
466 : dshash_table_handle hash_handle; /* shared dbstat hash */
467 :
468 : /* Has the stats system already been shut down? Just a debugging check. */
469 : bool is_shutdown;
470 :
471 : /*
472 : * Whenever statistics for dropped objects could not be freed - because
473 : * backends still have references - the dropping backend calls
474 : * pgstat_request_entry_refs_gc() incrementing this counter. Eventually
475 : * that causes backends to run pgstat_gc_entry_refs(), allowing memory to
476 : * be reclaimed.
477 : */
478 : pg_atomic_uint64 gc_request_count;
479 :
480 : /*
481 : * Stats data for fixed-numbered objects.
482 : */
483 : PgStatShared_Archiver archiver;
484 : PgStatShared_BgWriter bgwriter;
485 : PgStatShared_Checkpointer checkpointer;
486 : PgStatShared_IO io;
487 : PgStatShared_SLRU slru;
488 : PgStatShared_Wal wal;
489 :
490 : /*
491 : * Custom stats data with fixed-numbered objects, indexed by (PgStat_Kind
492 : * - PGSTAT_KIND_CUSTOM_MIN).
493 : */
494 : void *custom_data[PGSTAT_KIND_CUSTOM_SIZE];
495 :
496 : } PgStat_ShmemControl;
497 :
498 :
499 : /*
500 : * Cached statistics snapshot
501 : */
502 : typedef struct PgStat_Snapshot
503 : {
504 : PgStat_FetchConsistency mode;
505 :
506 : /* time at which snapshot was taken */
507 : TimestampTz snapshot_timestamp;
508 :
509 : bool fixed_valid[PGSTAT_KIND_BUILTIN_SIZE];
510 :
511 : PgStat_ArchiverStats archiver;
512 :
513 : PgStat_BgWriterStats bgwriter;
514 :
515 : PgStat_CheckpointerStats checkpointer;
516 :
517 : PgStat_IO io;
518 :
519 : PgStat_SLRUStats slru[SLRU_NUM_ELEMENTS];
520 :
521 : PgStat_WalStats wal;
522 :
523 : /*
524 : * Data in snapshot for custom fixed-numbered statistics, indexed by
525 : * (PgStat_Kind - PGSTAT_KIND_CUSTOM_MIN). Each entry is allocated in
526 : * TopMemoryContext, for a size of PgStat_KindInfo->shared_data_len.
527 : */
528 : bool custom_valid[PGSTAT_KIND_CUSTOM_SIZE];
529 : void *custom_data[PGSTAT_KIND_CUSTOM_SIZE];
530 :
531 : /* to free snapshot in bulk */
532 : MemoryContext context;
533 : struct pgstat_snapshot_hash *stats;
534 : } PgStat_Snapshot;
535 :
536 :
537 : /*
538 : * Collection of backend-local stats state.
539 : */
540 : typedef struct PgStat_LocalState
541 : {
542 : PgStat_ShmemControl *shmem;
543 : dsa_area *dsa;
544 : dshash_table *shared_hash;
545 :
546 : /* the current statistics snapshot */
547 : PgStat_Snapshot snapshot;
548 : } PgStat_LocalState;
549 :
550 :
551 : /*
552 : * Inline functions defined further below.
553 : */
554 :
555 : static inline void pgstat_begin_changecount_write(uint32 *cc);
556 : static inline void pgstat_end_changecount_write(uint32 *cc);
557 : static inline uint32 pgstat_begin_changecount_read(uint32 *cc);
558 : static inline bool pgstat_end_changecount_read(uint32 *cc, uint32 cc_before);
559 :
560 : static inline void pgstat_copy_changecounted_stats(void *dst, void *src, size_t len,
561 : uint32 *cc);
562 :
563 : static inline int pgstat_cmp_hash_key(const void *a, const void *b, size_t size, void *arg);
564 : static inline uint32 pgstat_hash_hash_key(const void *d, size_t size, void *arg);
565 : static inline size_t pgstat_get_entry_len(PgStat_Kind kind);
566 : static inline void *pgstat_get_entry_data(PgStat_Kind kind, PgStatShared_Common *entry);
567 : static inline void *pgstat_get_custom_shmem_data(PgStat_Kind kind);
568 : static inline void *pgstat_get_custom_snapshot_data(PgStat_Kind kind);
569 :
570 :
571 : /*
572 : * Functions in pgstat.c
573 : */
574 :
575 : extern const PgStat_KindInfo *pgstat_get_kind_info(PgStat_Kind kind);
576 : extern void pgstat_register_kind(PgStat_Kind kind,
577 : const PgStat_KindInfo *kind_info);
578 :
579 : #ifdef USE_ASSERT_CHECKING
580 : extern void pgstat_assert_is_up(void);
581 : #else
582 : #define pgstat_assert_is_up() ((void)true)
583 : #endif
584 :
585 : extern void pgstat_delete_pending_entry(PgStat_EntryRef *entry_ref);
586 : extern PgStat_EntryRef *pgstat_prep_pending_entry(PgStat_Kind kind, Oid dboid,
587 : uint64 objid,
588 : bool *created_entry);
589 : extern PgStat_EntryRef *pgstat_fetch_pending_entry(PgStat_Kind kind,
590 : Oid dboid, uint64 objid);
591 :
592 : extern void *pgstat_fetch_entry(PgStat_Kind kind, Oid dboid, uint64 objid);
593 : extern void pgstat_snapshot_fixed(PgStat_Kind kind);
594 :
595 :
596 : /*
597 : * Functions in pgstat_archiver.c
598 : */
599 :
600 : extern void pgstat_archiver_init_shmem_cb(void *stats);
601 : extern void pgstat_archiver_reset_all_cb(TimestampTz ts);
602 : extern void pgstat_archiver_snapshot_cb(void);
603 :
604 :
605 : /*
606 : * Functions in pgstat_bgwriter.c
607 : */
608 :
609 : extern void pgstat_bgwriter_init_shmem_cb(void *stats);
610 : extern void pgstat_bgwriter_reset_all_cb(TimestampTz ts);
611 : extern void pgstat_bgwriter_snapshot_cb(void);
612 :
613 :
614 : /*
615 : * Functions in pgstat_checkpointer.c
616 : */
617 :
618 : extern void pgstat_checkpointer_init_shmem_cb(void *stats);
619 : extern void pgstat_checkpointer_reset_all_cb(TimestampTz ts);
620 : extern void pgstat_checkpointer_snapshot_cb(void);
621 :
622 :
623 : /*
624 : * Functions in pgstat_database.c
625 : */
626 :
627 : extern void pgstat_report_disconnect(Oid dboid);
628 : extern void pgstat_update_dbstats(TimestampTz ts);
629 : extern void AtEOXact_PgStat_Database(bool isCommit, bool parallel);
630 :
631 : extern PgStat_StatDBEntry *pgstat_prep_database_pending(Oid dboid);
632 : extern void pgstat_reset_database_timestamp(Oid dboid, TimestampTz ts);
633 : extern bool pgstat_database_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
634 : extern void pgstat_database_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts);
635 :
636 :
637 : /*
638 : * Functions in pgstat_function.c
639 : */
640 :
641 : extern bool pgstat_function_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
642 :
643 :
644 : /*
645 : * Functions in pgstat_io.c
646 : */
647 :
648 : extern void pgstat_flush_io(bool nowait);
649 :
650 : extern bool pgstat_io_have_pending_cb(void);
651 : extern bool pgstat_io_flush_cb(bool nowait);
652 : extern void pgstat_io_init_shmem_cb(void *stats);
653 : extern void pgstat_io_reset_all_cb(TimestampTz ts);
654 : extern void pgstat_io_snapshot_cb(void);
655 :
656 :
657 : /*
658 : * Functions in pgstat_relation.c
659 : */
660 :
661 : extern void AtEOXact_PgStat_Relations(PgStat_SubXactStatus *xact_state, bool isCommit);
662 : extern void AtEOSubXact_PgStat_Relations(PgStat_SubXactStatus *xact_state, bool isCommit, int nestDepth);
663 : extern void AtPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state);
664 : extern void PostPrepare_PgStat_Relations(PgStat_SubXactStatus *xact_state);
665 :
666 : extern bool pgstat_relation_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
667 : extern void pgstat_relation_delete_pending_cb(PgStat_EntryRef *entry_ref);
668 :
669 :
670 : /*
671 : * Functions in pgstat_replslot.c
672 : */
673 :
674 : extern void pgstat_replslot_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts);
675 : extern void pgstat_replslot_to_serialized_name_cb(const PgStat_HashKey *key, const PgStatShared_Common *header, NameData *name);
676 : extern bool pgstat_replslot_from_serialized_name_cb(const NameData *name, PgStat_HashKey *key);
677 :
678 :
679 : /*
680 : * Functions in pgstat_shmem.c
681 : */
682 :
683 : extern void pgstat_attach_shmem(void);
684 : extern void pgstat_detach_shmem(void);
685 :
686 : extern PgStat_EntryRef *pgstat_get_entry_ref(PgStat_Kind kind, Oid dboid, uint64 objid,
687 : bool create, bool *created_entry);
688 : extern bool pgstat_lock_entry(PgStat_EntryRef *entry_ref, bool nowait);
689 : extern bool pgstat_lock_entry_shared(PgStat_EntryRef *entry_ref, bool nowait);
690 : extern void pgstat_unlock_entry(PgStat_EntryRef *entry_ref);
691 : extern bool pgstat_drop_entry(PgStat_Kind kind, Oid dboid, uint64 objid);
692 : extern void pgstat_drop_all_entries(void);
693 : extern PgStat_EntryRef *pgstat_get_entry_ref_locked(PgStat_Kind kind, Oid dboid, uint64 objid,
694 : bool nowait);
695 : extern void pgstat_reset_entry(PgStat_Kind kind, Oid dboid, uint64 objid, TimestampTz ts);
696 : extern void pgstat_reset_entries_of_kind(PgStat_Kind kind, TimestampTz ts);
697 : extern void pgstat_reset_matching_entries(bool (*do_reset) (PgStatShared_HashEntry *, Datum),
698 : Datum match_data,
699 : TimestampTz ts);
700 :
701 : extern void pgstat_request_entry_refs_gc(void);
702 : extern PgStatShared_Common *pgstat_init_entry(PgStat_Kind kind,
703 : PgStatShared_HashEntry *shhashent);
704 :
705 :
706 : /*
707 : * Functions in pgstat_slru.c
708 : */
709 :
710 : extern bool pgstat_slru_have_pending_cb(void);
711 : extern bool pgstat_slru_flush_cb(bool nowait);
712 : extern void pgstat_slru_init_shmem_cb(void *stats);
713 : extern void pgstat_slru_reset_all_cb(TimestampTz ts);
714 : extern void pgstat_slru_snapshot_cb(void);
715 :
716 :
717 : /*
718 : * Functions in pgstat_wal.c
719 : */
720 :
721 : extern void pgstat_flush_wal(bool nowait);
722 :
723 : extern void pgstat_wal_init_backend_cb(void);
724 : extern bool pgstat_wal_have_pending_cb(void);
725 : extern bool pgstat_wal_flush_cb(bool nowait);
726 : extern void pgstat_wal_init_shmem_cb(void *stats);
727 : extern void pgstat_wal_reset_all_cb(TimestampTz ts);
728 : extern void pgstat_wal_snapshot_cb(void);
729 :
730 :
731 : /*
732 : * Functions in pgstat_subscription.c
733 : */
734 :
735 : extern bool pgstat_subscription_flush_cb(PgStat_EntryRef *entry_ref, bool nowait);
736 : extern void pgstat_subscription_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts);
737 :
738 :
739 : /*
740 : * Functions in pgstat_xact.c
741 : */
742 :
743 : extern PgStat_SubXactStatus *pgstat_get_xact_stack_level(int nest_level);
744 : extern void pgstat_drop_transactional(PgStat_Kind kind, Oid dboid, uint64 objid);
745 : extern void pgstat_create_transactional(PgStat_Kind kind, Oid dboid, uint64 objid);
746 :
747 :
748 : /*
749 : * Variables in pgstat.c
750 : */
751 :
752 : extern PGDLLIMPORT PgStat_LocalState pgStatLocal;
753 :
754 :
755 : /*
756 : * Implementation of inline functions declared above.
757 : */
758 :
759 : /*
760 : * Helpers for changecount manipulation. See comments around struct
761 : * PgBackendStatus for details.
762 : */
763 :
764 : static inline void
765 18452 : pgstat_begin_changecount_write(uint32 *cc)
766 : {
767 : Assert((*cc & 1) == 0);
768 :
769 18452 : START_CRIT_SECTION();
770 18452 : (*cc)++;
771 18452 : pg_write_barrier();
772 18452 : }
773 :
774 : static inline void
775 18452 : pgstat_end_changecount_write(uint32 *cc)
776 : {
777 : Assert((*cc & 1) == 1);
778 :
779 18452 : pg_write_barrier();
780 :
781 18452 : (*cc)++;
782 :
783 18452 : END_CRIT_SECTION();
784 18452 : }
785 :
786 : static inline uint32
787 4918 : pgstat_begin_changecount_read(uint32 *cc)
788 : {
789 4918 : uint32 before_cc = *cc;
790 :
791 4918 : CHECK_FOR_INTERRUPTS();
792 :
793 4918 : pg_read_barrier();
794 :
795 4918 : return before_cc;
796 : }
797 :
798 : /*
799 : * Returns true if the read succeeded, false if it needs to be repeated.
800 : */
801 : static inline bool
802 4918 : pgstat_end_changecount_read(uint32 *cc, uint32 before_cc)
803 : {
804 : uint32 after_cc;
805 :
806 4918 : pg_read_barrier();
807 :
808 4918 : after_cc = *cc;
809 :
810 : /* was a write in progress when we started? */
811 4918 : if (before_cc & 1)
812 0 : return false;
813 :
814 : /* did writes start and complete while we read? */
815 4918 : return before_cc == after_cc;
816 : }
817 :
818 :
819 : /*
820 : * helper function for PgStat_KindInfo->snapshot_cb
821 : * PgStat_KindInfo->reset_all_cb callbacks.
822 : *
823 : * Copies out the specified memory area following change-count protocol.
824 : */
825 : static inline void
826 4918 : pgstat_copy_changecounted_stats(void *dst, void *src, size_t len,
827 : uint32 *cc)
828 : {
829 : uint32 cc_before;
830 :
831 : do
832 : {
833 4918 : cc_before = pgstat_begin_changecount_read(cc);
834 :
835 4918 : memcpy(dst, src, len);
836 : }
837 4918 : while (!pgstat_end_changecount_read(cc, cc_before));
838 4918 : }
839 :
840 : /* helpers for dshash / simplehash hashtables */
841 : static inline int
842 7677176 : pgstat_cmp_hash_key(const void *a, const void *b, size_t size, void *arg)
843 : {
844 : Assert(size == sizeof(PgStat_HashKey) && arg == NULL);
845 7677176 : return memcmp(a, b, sizeof(PgStat_HashKey));
846 : }
847 :
848 : static inline uint32
849 9818600 : pgstat_hash_hash_key(const void *d, size_t size, void *arg)
850 : {
851 9818600 : const char *key = (const char *) d;
852 :
853 : Assert(size == sizeof(PgStat_HashKey) && arg == NULL);
854 9818600 : return fasthash32(key, size, 0);
855 : }
856 :
857 : /*
858 : * The length of the data portion of a shared memory stats entry (i.e. without
859 : * transient data such as refcounts, lwlocks, ...).
860 : */
861 : static inline size_t
862 646232 : pgstat_get_entry_len(PgStat_Kind kind)
863 : {
864 646232 : return pgstat_get_kind_info(kind)->shared_data_len;
865 : }
866 :
867 : /*
868 : * Returns a pointer to the data portion of a shared memory stats entry.
869 : */
870 : static inline void *
871 880934 : pgstat_get_entry_data(PgStat_Kind kind, PgStatShared_Common *entry)
872 : {
873 880934 : size_t off = pgstat_get_kind_info(kind)->shared_data_off;
874 :
875 : Assert(off != 0 && off < PG_UINT32_MAX);
876 :
877 880934 : return ((char *) (entry)) + off;
878 : }
879 :
880 : /*
881 : * Returns a pointer to the shared memory area of custom stats for
882 : * fixed-numbered statistics.
883 : */
884 : static inline void *
885 24 : pgstat_get_custom_shmem_data(PgStat_Kind kind)
886 : {
887 24 : int idx = kind - PGSTAT_KIND_CUSTOM_MIN;
888 :
889 : Assert(pgstat_is_kind_custom(kind));
890 : Assert(pgstat_get_kind_info(kind)->fixed_amount);
891 :
892 24 : return pgStatLocal.shmem->custom_data[idx];
893 : }
894 :
895 : /*
896 : * Returns a pointer to the portion of custom data for fixed-numbered
897 : * statistics in the current snapshot.
898 : */
899 : static inline void *
900 18 : pgstat_get_custom_snapshot_data(PgStat_Kind kind)
901 : {
902 18 : int idx = kind - PGSTAT_KIND_CUSTOM_MIN;
903 :
904 : Assert(pgstat_is_kind_custom(kind));
905 : Assert(pgstat_get_kind_info(kind)->fixed_amount);
906 :
907 18 : return pgStatLocal.snapshot.custom_data[idx];
908 : }
909 :
910 : #endif /* PGSTAT_INTERNAL_H */
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