PostgreSQL Source Code git master
Data Structures | Macros | Typedefs | Functions | Variables
sync.c File Reference
#include "postgres.h"
#include <unistd.h>
#include <fcntl.h>
#include <sys/file.h>
#include "access/clog.h"
#include "access/commit_ts.h"
#include "access/multixact.h"
#include "access/xlog.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "portability/instr_time.h"
#include "postmaster/bgwriter.h"
#include "storage/fd.h"
#include "storage/latch.h"
#include "storage/md.h"
#include "utils/hsearch.h"
#include "utils/memutils.h"
Include dependency graph for sync.c:

Go to the source code of this file.

Data Structures

struct   PendingFsyncEntry
 
struct   PendingUnlinkEntry
 
struct   SyncOps
 

Macros

#define  FSYNCS_PER_ABSORB   10
 
#define  UNLINKS_PER_ABSORB   10
 

Typedefs

typedef uint16  CycleCtr
 
typedef struct SyncOps  SyncOps
 

Functions

void  InitSync (void)
 
void  SyncPreCheckpoint (void)
 
void  SyncPostCheckpoint (void)
 
void  ProcessSyncRequests (void)
 
void  RememberSyncRequest (const FileTag *ftag, SyncRequestType type)
 
bool  RegisterSyncRequest (const FileTag *ftag, SyncRequestType type, bool retryOnError)
 

Variables

static HTAB *  pendingOps = NULL
 
static List *  pendingUnlinks = NIL
 
static MemoryContext  pendingOpsCxt
 
static CycleCtr  sync_cycle_ctr = 0
 
static CycleCtr  checkpoint_cycle_ctr = 0
 
static const SyncOps  syncsw []
 

Macro Definition Documentation

◆ FSYNCS_PER_ABSORB

#define FSYNCS_PER_ABSORB   10

Definition at line 78 of file sync.c.

◆ UNLINKS_PER_ABSORB

#define UNLINKS_PER_ABSORB   10

Definition at line 79 of file sync.c.

Typedef Documentation

◆ CycleCtr

typedef uint16 CycleCtr

Definition at line 54 of file sync.c.

◆ SyncOps

typedef struct SyncOps SyncOps

Function Documentation

◆ InitSync()

void InitSync ( void  )

Definition at line 124 of file sync.c.

125{
126 /*
127 * Create pending-operations hashtable if we need it. Currently, we need
128 * it if we are standalone (not under a postmaster) or if we are a
129 * checkpointer auxiliary process.
130 */
132 {
133 HASHCTL hash_ctl;
134
135 /*
136 * XXX: The checkpointer needs to add entries to the pending ops table
137 * when absorbing fsync requests. That is done within a critical
138 * section, which isn't usually allowed, but we make an exception. It
139 * means that there's a theoretical possibility that you run out of
140 * memory while absorbing fsync requests, which leads to a PANIC.
141 * Fortunately the hash table is small so that's unlikely to happen in
142 * practice.
143 */
145 "Pending ops context",
148
149 hash_ctl.keysize = sizeof(FileTag);
150 hash_ctl.entrysize = sizeof(PendingFsyncEntry);
151 hash_ctl.hcxt = pendingOpsCxt;
152 pendingOps = hash_create("Pending Ops Table",
153 100L,
154 &hash_ctl,
157 }
158}
HTAB * hash_create(const char *tabname, int64 nelem, const HASHCTL *info, int flags)
Definition: dynahash.c:358
bool IsUnderPostmaster
Definition: globals.c:120
#define HASH_CONTEXT
Definition: hsearch.h:102
#define HASH_ELEM
Definition: hsearch.h:95
#define HASH_BLOBS
Definition: hsearch.h:97
MemoryContext TopMemoryContext
Definition: mcxt.c:166
void MemoryContextAllowInCriticalSection(MemoryContext context, bool allow)
Definition: mcxt.c:740
#define AllocSetContextCreate
Definition: memutils.h:129
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:160
#define AmCheckpointerProcess()
Definition: miscadmin.h:388
#define NIL
Definition: pg_list.h:68
Definition: hsearch.h:66
Size keysize
Definition: hsearch.h:75
Size entrysize
Definition: hsearch.h:76
MemoryContext hcxt
Definition: hsearch.h:86
static List * pendingUnlinks
Definition: sync.c:71
static HTAB * pendingOps
Definition: sync.c:70
static MemoryContext pendingOpsCxt
Definition: sync.c:72
struct FileTag FileTag

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, AmCheckpointerProcess, HASHCTL::entrysize, HASH_BLOBS, HASH_CONTEXT, hash_create(), HASH_ELEM, HASHCTL::hcxt, IsUnderPostmaster, HASHCTL::keysize, MemoryContextAllowInCriticalSection(), NIL, pendingOps, pendingOpsCxt, pendingUnlinks, and TopMemoryContext.

Referenced by BaseInit().

◆ ProcessSyncRequests()

void ProcessSyncRequests ( void  )

Definition at line 286 of file sync.c.

287{
288 static bool sync_in_progress = false;
289
290 HASH_SEQ_STATUS hstat;
291 PendingFsyncEntry *entry;
292 int absorb_counter;
293
294 /* Statistics on sync times */
295 int processed = 0;
296 instr_time sync_start,
297 sync_end,
298 sync_diff;
299 uint64 elapsed;
300 uint64 longest = 0;
301 uint64 total_elapsed = 0;
302
303 /*
304 * This is only called during checkpoints, and checkpoints should only
305 * occur in processes that have created a pendingOps.
306 */
307 if (!pendingOps)
308 elog(ERROR, "cannot sync without a pendingOps table");
309
310 /*
311 * If we are in the checkpointer, the sync had better include all fsync
312 * requests that were queued by backends up to this point. The tightest
313 * race condition that could occur is that a buffer that must be written
314 * and fsync'd for the checkpoint could have been dumped by a backend just
315 * before it was visited by BufferSync(). We know the backend will have
316 * queued an fsync request before clearing the buffer's dirtybit, so we
317 * are safe as long as we do an Absorb after completing BufferSync().
318 */
320
321 /*
322 * To avoid excess fsync'ing (in the worst case, maybe a never-terminating
323 * checkpoint), we want to ignore fsync requests that are entered into the
324 * hashtable after this point --- they should be processed next time,
325 * instead. We use sync_cycle_ctr to tell old entries apart from new
326 * ones: new ones will have cycle_ctr equal to the incremented value of
327 * sync_cycle_ctr.
328 *
329 * In normal circumstances, all entries present in the table at this point
330 * will have cycle_ctr exactly equal to the current (about to be old)
331 * value of sync_cycle_ctr. However, if we fail partway through the
332 * fsync'ing loop, then older values of cycle_ctr might remain when we
333 * come back here to try again. Repeated checkpoint failures would
334 * eventually wrap the counter around to the point where an old entry
335 * might appear new, causing us to skip it, possibly allowing a checkpoint
336 * to succeed that should not have. To forestall wraparound, any time the
337 * previous ProcessSyncRequests() failed to complete, run through the
338 * table and forcibly set cycle_ctr = sync_cycle_ctr.
339 *
340 * Think not to merge this loop with the main loop, as the problem is
341 * exactly that that loop may fail before having visited all the entries.
342 * From a performance point of view it doesn't matter anyway, as this path
343 * will never be taken in a system that's functioning normally.
344 */
345 if (sync_in_progress)
346 {
347 /* prior try failed, so update any stale cycle_ctr values */
348 hash_seq_init(&hstat, pendingOps);
349 while ((entry = (PendingFsyncEntry *) hash_seq_search(&hstat)) != NULL)
350 {
351 entry->cycle_ctr = sync_cycle_ctr;
352 }
353 }
354
355 /* Advance counter so that new hashtable entries are distinguishable */
357
358 /* Set flag to detect failure if we don't reach the end of the loop */
359 sync_in_progress = true;
360
361 /* Now scan the hashtable for fsync requests to process */
362 absorb_counter = FSYNCS_PER_ABSORB;
363 hash_seq_init(&hstat, pendingOps);
364 while ((entry = (PendingFsyncEntry *) hash_seq_search(&hstat)) != NULL)
365 {
366 int failures;
367
368 /*
369 * If the entry is new then don't process it this time; it is new.
370 * Note "continue" bypasses the hash-remove call at the bottom of the
371 * loop.
372 */
373 if (entry->cycle_ctr == sync_cycle_ctr)
374 continue;
375
376 /* Else assert we haven't missed it */
377 Assert((CycleCtr) (entry->cycle_ctr + 1) == sync_cycle_ctr);
378
379 /*
380 * If fsync is off then we don't have to bother opening the file at
381 * all. (We delay checking until this point so that changing fsync on
382 * the fly behaves sensibly.)
383 */
384 if (enableFsync)
385 {
386 /*
387 * If in checkpointer, we want to absorb pending requests every so
388 * often to prevent overflow of the fsync request queue. It is
389 * unspecified whether newly-added entries will be visited by
390 * hash_seq_search, but we don't care since we don't need to
391 * process them anyway.
392 */
393 if (--absorb_counter <= 0)
394 {
396 absorb_counter = FSYNCS_PER_ABSORB;
397 }
398
399 /*
400 * The fsync table could contain requests to fsync segments that
401 * have been deleted (unlinked) by the time we get to them. Rather
402 * than just hoping an ENOENT (or EACCES on Windows) error can be
403 * ignored, what we do on error is absorb pending requests and
404 * then retry. Since mdunlink() queues a "cancel" message before
405 * actually unlinking, the fsync request is guaranteed to be
406 * marked canceled after the absorb if it really was this case.
407 * DROP DATABASE likewise has to tell us to forget fsync requests
408 * before it starts deletions.
409 */
410 for (failures = 0; !entry->canceled; failures++)
411 {
412 char path[MAXPGPATH];
413
414 INSTR_TIME_SET_CURRENT(sync_start);
415 if (syncsw[entry->tag.handler].sync_syncfiletag(&entry->tag,
416 path) == 0)
417 {
418 /* Success; update statistics about sync timing */
419 INSTR_TIME_SET_CURRENT(sync_end);
420 sync_diff = sync_end;
421 INSTR_TIME_SUBTRACT(sync_diff, sync_start);
422 elapsed = INSTR_TIME_GET_MICROSEC(sync_diff);
423 if (elapsed > longest)
424 longest = elapsed;
425 total_elapsed += elapsed;
426 processed++;
427
428 if (log_checkpoints)
429 elog(DEBUG1, "checkpoint sync: number=%d file=%s time=%.3f ms",
430 processed,
431 path,
432 (double) elapsed / 1000);
433
434 break; /* out of retry loop */
435 }
436
437 /*
438 * It is possible that the relation has been dropped or
439 * truncated since the fsync request was entered. Therefore,
440 * allow ENOENT, but only if we didn't fail already on this
441 * file.
442 */
443 if (!FILE_POSSIBLY_DELETED(errno) || failures > 0)
446 errmsg("could not fsync file \"%s\": %m",
447 path)));
448 else
451 errmsg_internal("could not fsync file \"%s\" but retrying: %m",
452 path)));
453
454 /*
455 * Absorb incoming requests and check to see if a cancel
456 * arrived for this relation fork.
457 */
459 absorb_counter = FSYNCS_PER_ABSORB; /* might as well... */
460 } /* end retry loop */
461 }
462
463 /* We are done with this entry, remove it */
464 if (hash_search(pendingOps, &entry->tag, HASH_REMOVE, NULL) == NULL)
465 elog(ERROR, "pendingOps corrupted");
466 } /* end loop over hashtable entries */
467
468 /* Return sync performance metrics for report at checkpoint end */
471 CheckpointStats.ckpt_agg_sync_time = total_elapsed;
472
473 /* Flag successful completion of ProcessSyncRequests */
474 sync_in_progress = false;
475}
uint64_t uint64
Definition: c.h:539
void AbsorbSyncRequests(void)
Definition: checkpointer.c:1429
void * hash_search(HTAB *hashp, const void *keyPtr, HASHACTION action, bool *foundPtr)
Definition: dynahash.c:952
void * hash_seq_search(HASH_SEQ_STATUS *status)
Definition: dynahash.c:1415
void hash_seq_init(HASH_SEQ_STATUS *status, HTAB *hashp)
Definition: dynahash.c:1380
int errmsg_internal(const char *fmt,...)
Definition: elog.c:1161
int errcode_for_file_access(void)
Definition: elog.c:877
int errmsg(const char *fmt,...)
Definition: elog.c:1071
#define DEBUG1
Definition: elog.h:30
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:226
#define ereport(elevel,...)
Definition: elog.h:150
int data_sync_elevel(int elevel)
Definition: fd.c:3998
#define FILE_POSSIBLY_DELETED(err)
Definition: fd.h:78
bool enableFsync
Definition: globals.c:129
Assert(PointerIsAligned(start, uint64))
@ HASH_REMOVE
Definition: hsearch.h:115
#define INSTR_TIME_SET_CURRENT(t)
Definition: instr_time.h:122
#define INSTR_TIME_SUBTRACT(x, y)
Definition: instr_time.h:181
#define INSTR_TIME_GET_MICROSEC(t)
Definition: instr_time.h:194
#define MAXPGPATH
static chr * longest(struct vars *v, struct dfa *d, chr *start, chr *stop, int *hitstopp)
Definition: rege_dfa.c:42
uint64 ckpt_agg_sync_time
Definition: xlog.h:176
uint64 ckpt_longest_sync
Definition: xlog.h:175
int ckpt_sync_rels
Definition: xlog.h:174
int16 handler
Definition: sync.h:52
Definition: hsearch.h:121
FileTag tag
Definition: sync.c:58
CycleCtr cycle_ctr
Definition: sync.c:59
bool canceled
Definition: sync.c:60
int(* sync_syncfiletag)(const FileTag *ftag, char *path)
Definition: sync.c:86
Definition: instr_time.h:70
static const SyncOps syncsw[]
Definition: sync.c:95
static CycleCtr sync_cycle_ctr
Definition: sync.c:74
#define FSYNCS_PER_ABSORB
Definition: sync.c:78
uint16 CycleCtr
Definition: sync.c:54
bool log_checkpoints
Definition: xlog.c:130
CheckpointStatsData CheckpointStats
Definition: xlog.c:210

References AbsorbSyncRequests(), Assert(), PendingFsyncEntry::canceled, CheckpointStats, CheckpointStatsData::ckpt_agg_sync_time, CheckpointStatsData::ckpt_longest_sync, CheckpointStatsData::ckpt_sync_rels, PendingFsyncEntry::cycle_ctr, data_sync_elevel(), DEBUG1, elog, enableFsync, ereport, errcode_for_file_access(), errmsg(), errmsg_internal(), ERROR, FILE_POSSIBLY_DELETED, FSYNCS_PER_ABSORB, FileTag::handler, HASH_REMOVE, hash_search(), hash_seq_init(), hash_seq_search(), INSTR_TIME_GET_MICROSEC, INSTR_TIME_SET_CURRENT, INSTR_TIME_SUBTRACT, log_checkpoints, longest(), MAXPGPATH, pendingOps, sync_cycle_ctr, SyncOps::sync_syncfiletag, syncsw, and PendingFsyncEntry::tag.

Referenced by CheckPointGuts().

◆ RegisterSyncRequest()

bool RegisterSyncRequest ( const FileTag *  ftag,
SyncRequestType  type,
bool  retryOnError 
)

Definition at line 580 of file sync.c.

582{
583 bool ret;
584
585 if (pendingOps != NULL)
586 {
587 /* standalone backend or startup process: fsync state is local */
589 return true;
590 }
591
592 for (;;)
593 {
594 /*
595 * Notify the checkpointer about it. If we fail to queue a message in
596 * retryOnError mode, we have to sleep and try again ... ugly, but
597 * hopefully won't happen often.
598 *
599 * XXX should we CHECK_FOR_INTERRUPTS in this loop? Escaping with an
600 * error in the case of SYNC_UNLINK_REQUEST would leave the
601 * no-longer-used file still present on disk, which would be bad, so
602 * I'm inclined to assume that the checkpointer will always empty the
603 * queue soon.
604 */
605 ret = ForwardSyncRequest(ftag, type);
606
607 /*
608 * If we are successful in queueing the request, or we failed and were
609 * instructed not to retry on error, break.
610 */
611 if (ret || (!ret && !retryOnError))
612 break;
613
615 WAIT_EVENT_REGISTER_SYNC_REQUEST);
616 }
617
618 return ret;
619}
bool ForwardSyncRequest(const FileTag *ftag, SyncRequestType type)
Definition: checkpointer.c:1217
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:172
void RememberSyncRequest(const FileTag *ftag, SyncRequestType type)
Definition: sync.c:487
const char * type
#define WL_TIMEOUT
Definition: waiteventset.h:37
#define WL_EXIT_ON_PM_DEATH
Definition: waiteventset.h:39

References ForwardSyncRequest(), pendingOps, RememberSyncRequest(), type, WaitLatch(), WL_EXIT_ON_PM_DEATH, and WL_TIMEOUT.

Referenced by ForgetDatabaseSyncRequests(), register_dirty_segment(), register_forget_request(), register_unlink_segment(), SlruInternalDeleteSegment(), and SlruPhysicalWritePage().

◆ RememberSyncRequest()

void RememberSyncRequest ( const FileTag *  ftag,
SyncRequestType  type 
)

Definition at line 487 of file sync.c.

488{
490
492 {
493 PendingFsyncEntry *entry;
494
495 /* Cancel previously entered request */
497 ftag,
498 HASH_FIND,
499 NULL);
500 if (entry != NULL)
501 entry->canceled = true;
502 }
503 else if (type == SYNC_FILTER_REQUEST)
504 {
505 HASH_SEQ_STATUS hstat;
507 ListCell *cell;
508
509 /* Cancel matching fsync requests */
510 hash_seq_init(&hstat, pendingOps);
511 while ((pfe = (PendingFsyncEntry *) hash_seq_search(&hstat)) != NULL)
512 {
513 if (pfe->tag.handler == ftag->handler &&
514 syncsw[ftag->handler].sync_filetagmatches(ftag, &pfe->tag))
515 pfe->canceled = true;
516 }
517
518 /* Cancel matching unlink requests */
519 foreach(cell, pendingUnlinks)
520 {
522
523 if (pue->tag.handler == ftag->handler &&
524 syncsw[ftag->handler].sync_filetagmatches(ftag, &pue->tag))
525 pue->canceled = true;
526 }
527 }
528 else if (type == SYNC_UNLINK_REQUEST)
529 {
530 /* Unlink request: put it in the linked list */
532 PendingUnlinkEntry *entry;
533
534 entry = palloc(sizeof(PendingUnlinkEntry));
535 entry->tag = *ftag;
537 entry->canceled = false;
538
540
541 MemoryContextSwitchTo(oldcxt);
542 }
543 else
544 {
545 /* Normal case: enter a request to fsync this segment */
547 PendingFsyncEntry *entry;
548 bool found;
549
551
553 ftag,
555 &found);
556 /* if new entry, or was previously canceled, initialize it */
557 if (!found || entry->canceled)
558 {
559 entry->cycle_ctr = sync_cycle_ctr;
560 entry->canceled = false;
561 }
562
563 /*
564 * NB: it's intentional that we don't change cycle_ctr if the entry
565 * already exists. The cycle_ctr must represent the oldest fsync
566 * request that could be in the entry.
567 */
568
569 MemoryContextSwitchTo(oldcxt);
570 }
571}
@ HASH_FIND
Definition: hsearch.h:113
@ HASH_ENTER
Definition: hsearch.h:114
List * lappend(List *list, void *datum)
Definition: list.c:339
void * palloc(Size size)
Definition: mcxt.c:1365
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:124
#define lfirst(lc)
Definition: pg_list.h:172
FileTag tag
Definition: sync.c:65
CycleCtr cycle_ctr
Definition: sync.c:66
bool canceled
Definition: sync.c:67
bool(* sync_filetagmatches)(const FileTag *ftag, const FileTag *candidate)
Definition: sync.c:88
static CycleCtr checkpoint_cycle_ctr
Definition: sync.c:75
@ SYNC_FILTER_REQUEST
Definition: sync.h:28
@ SYNC_FORGET_REQUEST
Definition: sync.h:27
@ SYNC_UNLINK_REQUEST
Definition: sync.h:26
@ SYNC_REQUEST
Definition: sync.h:25
Definition: pg_list.h:46

References Assert(), PendingFsyncEntry::canceled, PendingUnlinkEntry::canceled, checkpoint_cycle_ctr, PendingFsyncEntry::cycle_ctr, PendingUnlinkEntry::cycle_ctr, FileTag::handler, HASH_ENTER, HASH_FIND, hash_search(), hash_seq_init(), hash_seq_search(), lappend(), lfirst, MemoryContextSwitchTo(), palloc(), pendingOps, pendingOpsCxt, pendingUnlinks, sync_cycle_ctr, SyncOps::sync_filetagmatches, SYNC_FILTER_REQUEST, SYNC_FORGET_REQUEST, SYNC_REQUEST, SYNC_UNLINK_REQUEST, syncsw, PendingFsyncEntry::tag, PendingUnlinkEntry::tag, and type.

Referenced by AbsorbSyncRequests(), and RegisterSyncRequest().

◆ SyncPostCheckpoint()

void SyncPostCheckpoint ( void  )

Definition at line 202 of file sync.c.

203{
204 int absorb_counter;
205 ListCell *lc;
206
207 absorb_counter = UNLINKS_PER_ABSORB;
208 foreach(lc, pendingUnlinks)
209 {
211 char path[MAXPGPATH];
212
213 /* Skip over any canceled entries */
214 if (entry->canceled)
215 continue;
216
217 /*
218 * New entries are appended to the end, so if the entry is new we've
219 * reached the end of old entries.
220 *
221 * Note: if just the right number of consecutive checkpoints fail, we
222 * could be fooled here by cycle_ctr wraparound. However, the only
223 * consequence is that we'd delay unlinking for one more checkpoint,
224 * which is perfectly tolerable.
225 */
226 if (entry->cycle_ctr == checkpoint_cycle_ctr)
227 break;
228
229 /* Unlink the file */
230 if (syncsw[entry->tag.handler].sync_unlinkfiletag(&entry->tag,
231 path) < 0)
232 {
233 /*
234 * There's a race condition, when the database is dropped at the
235 * same time that we process the pending unlink requests. If the
236 * DROP DATABASE deletes the file before we do, we will get ENOENT
237 * here. rmtree() also has to ignore ENOENT errors, to deal with
238 * the possibility that we delete the file first.
239 */
240 if (errno != ENOENT)
243 errmsg("could not remove file \"%s\": %m", path)));
244 }
245
246 /* Mark the list entry as canceled, just in case */
247 entry->canceled = true;
248
249 /*
250 * As in ProcessSyncRequests, we don't want to stop absorbing fsync
251 * requests for a long time when there are many deletions to be done.
252 * We can safely call AbsorbSyncRequests() at this point in the loop.
253 */
254 if (--absorb_counter <= 0)
255 {
257 absorb_counter = UNLINKS_PER_ABSORB;
258 }
259 }
260
261 /*
262 * If we reached the end of the list, we can just remove the whole list
263 * (remembering to pfree all the PendingUnlinkEntry objects). Otherwise,
264 * we must keep the entries at or after "lc".
265 */
266 if (lc == NULL)
267 {
270 }
271 else
272 {
273 int ntodelete = list_cell_number(pendingUnlinks, lc);
274
275 for (int i = 0; i < ntodelete; i++)
277
279 }
280}
#define WARNING
Definition: elog.h:36
i
int i
Definition: isn.c:77
List * list_delete_first_n(List *list, int n)
Definition: list.c:983
void list_free_deep(List *list)
Definition: list.c:1560
void pfree(void *pointer)
Definition: mcxt.c:1594
static void * list_nth(const List *list, int n)
Definition: pg_list.h:299
static int list_cell_number(const List *l, const ListCell *c)
Definition: pg_list.h:333
int(* sync_unlinkfiletag)(const FileTag *ftag, char *path)
Definition: sync.c:87
#define UNLINKS_PER_ABSORB
Definition: sync.c:79

References AbsorbSyncRequests(), PendingUnlinkEntry::canceled, checkpoint_cycle_ctr, PendingUnlinkEntry::cycle_ctr, ereport, errcode_for_file_access(), errmsg(), FileTag::handler, i, lfirst, list_cell_number(), list_delete_first_n(), list_free_deep(), list_nth(), MAXPGPATH, NIL, pendingUnlinks, pfree(), SyncOps::sync_unlinkfiletag, syncsw, PendingUnlinkEntry::tag, UNLINKS_PER_ABSORB, and WARNING.

Referenced by CreateCheckPoint().

◆ SyncPreCheckpoint()

void SyncPreCheckpoint ( void  )

Definition at line 177 of file sync.c.

178{
179 /*
180 * Operations such as DROP TABLESPACE assume that the next checkpoint will
181 * process all recently forwarded unlink requests, but if they aren't
182 * absorbed prior to advancing the cycle counter, they won't be processed
183 * until a future checkpoint. The following absorb ensures that any
184 * unlink requests forwarded before the checkpoint began will be processed
185 * in the current checkpoint.
186 */
188
189 /*
190 * Any unlink requests arriving after this point will be assigned the next
191 * cycle counter, and won't be unlinked until next checkpoint.
192 */
194}

References AbsorbSyncRequests(), and checkpoint_cycle_ctr.

Referenced by CreateCheckPoint().

Variable Documentation

◆ checkpoint_cycle_ctr

CycleCtr checkpoint_cycle_ctr = 0
static

Definition at line 75 of file sync.c.

Referenced by RememberSyncRequest(), SyncPostCheckpoint(), and SyncPreCheckpoint().

◆ pendingOps

HTAB* pendingOps = NULL
static

Definition at line 70 of file sync.c.

Referenced by InitSync(), ProcessSyncRequests(), RegisterSyncRequest(), and RememberSyncRequest().

◆ pendingOpsCxt

MemoryContext pendingOpsCxt
static

Definition at line 72 of file sync.c.

Referenced by InitSync(), and RememberSyncRequest().

◆ pendingUnlinks

List* pendingUnlinks = NIL
static

Definition at line 71 of file sync.c.

Referenced by InitSync(), RememberSyncRequest(), and SyncPostCheckpoint().

◆ sync_cycle_ctr

CycleCtr sync_cycle_ctr = 0
static

Definition at line 74 of file sync.c.

Referenced by ProcessSyncRequests(), and RememberSyncRequest().

◆ syncsw

const SyncOps syncsw[]
static
Initial value:
= {
.sync_syncfiletag = mdsyncfiletag,
.sync_unlinkfiletag = mdunlinkfiletag,
.sync_filetagmatches = mdfiletagmatches
},
.sync_syncfiletag = clogsyncfiletag
},
.sync_syncfiletag = committssyncfiletag
},
.sync_syncfiletag = multixactoffsetssyncfiletag
},
.sync_syncfiletag = multixactmemberssyncfiletag
}
}
int clogsyncfiletag(const FileTag *ftag, char *path)
Definition: clog.c:1094
int committssyncfiletag(const FileTag *ftag, char *path)
Definition: commit_ts.c:1020
bool mdfiletagmatches(const FileTag *ftag, const FileTag *candidate)
Definition: md.c:1950
int mdunlinkfiletag(const FileTag *ftag, char *path)
Definition: md.c:1932
int mdsyncfiletag(const FileTag *ftag, char *path)
Definition: md.c:1880
int multixactoffsetssyncfiletag(const FileTag *ftag, char *path)
Definition: multixact.c:3429
int multixactmemberssyncfiletag(const FileTag *ftag, char *path)
Definition: multixact.c:3438
@ SYNC_HANDLER_MD
Definition: sync.h:37
@ SYNC_HANDLER_COMMIT_TS
Definition: sync.h:39
@ SYNC_HANDLER_MULTIXACT_MEMBER
Definition: sync.h:41
@ SYNC_HANDLER_CLOG
Definition: sync.h:38
@ SYNC_HANDLER_MULTIXACT_OFFSET
Definition: sync.h:40

Definition at line 95 of file sync.c.

Referenced by ProcessSyncRequests(), RememberSyncRequest(), and SyncPostCheckpoint().

AltStyle によって変換されたページ (->オリジナル) /