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bgwriter.h File Reference
#include "storage/block.h"
#include "storage/relfilelocator.h"
#include "storage/smgr.h"
#include "storage/sync.h"
Include dependency graph for bgwriter.h:
This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Functions

void BackgroundWriterMain (char *startup_data, size_t startup_data_len) pg_attribute_noreturn()
 
void CheckpointerMain (char *startup_data, size_t startup_data_len) pg_attribute_noreturn()
 
void RequestCheckpoint (int flags)
 
void CheckpointWriteDelay (int flags, double progress)
 
bool ForwardSyncRequest (const FileTag *ftag, SyncRequestType type)
 
void AbsorbSyncRequests (void)
 
Size CheckpointerShmemSize (void)
 
void CheckpointerShmemInit (void)
 
bool FirstCallSinceLastCheckpoint (void)
 

Variables

PGDLLIMPORT int BgWriterDelay
 
PGDLLIMPORT int CheckPointTimeout
 
PGDLLIMPORT int CheckPointWarning
 
PGDLLIMPORT double CheckPointCompletionTarget
 

Function Documentation

◆ AbsorbSyncRequests()

void AbsorbSyncRequests ( void  )

Definition at line 1281 of file checkpointer.c.

1282{
1283 CheckpointerRequest *requests = NULL;
1284 CheckpointerRequest *request;
1285 int n;
1286
1287 if (!AmCheckpointerProcess())
1288 return;
1289
1290 LWLockAcquire(CheckpointerCommLock, LW_EXCLUSIVE);
1291
1292 /*
1293 * We try to avoid holding the lock for a long time by copying the request
1294 * array, and processing the requests after releasing the lock.
1295 *
1296 * Once we have cleared the requests from shared memory, we have to PANIC
1297 * if we then fail to absorb them (eg, because our hashtable runs out of
1298 * memory). This is because the system cannot run safely if we are unable
1299 * to fsync what we have been told to fsync. Fortunately, the hashtable
1300 * is so small that the problem is quite unlikely to arise in practice.
1301 */
1303 if (n > 0)
1304 {
1305 requests = (CheckpointerRequest *) palloc(n * sizeof(CheckpointerRequest));
1306 memcpy(requests, CheckpointerShmem->requests, n * sizeof(CheckpointerRequest));
1307 }
1308
1310
1312
1313 LWLockRelease(CheckpointerCommLock);
1314
1315 for (request = requests; n > 0; request++, n--)
1316 RememberSyncRequest(&request->ftag, request->type);
1317
1319
1320 if (requests)
1321 pfree(requests);
1322}
static CheckpointerShmemStruct * CheckpointerShmem
Definition: checkpointer.c:128
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1168
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1781
@ LW_EXCLUSIVE
Definition: lwlock.h:114
void pfree(void *pointer)
Definition: mcxt.c:1521
void * palloc(Size size)
Definition: mcxt.c:1317
#define AmCheckpointerProcess()
Definition: miscadmin.h:387
#define START_CRIT_SECTION()
Definition: miscadmin.h:149
#define END_CRIT_SECTION()
Definition: miscadmin.h:151
SyncRequestType type
Definition: checkpointer.c:104
CheckpointerRequest requests[FLEXIBLE_ARRAY_MEMBER]
Definition: checkpointer.c:125
void RememberSyncRequest(const FileTag *ftag, SyncRequestType type)
Definition: sync.c:487

References AmCheckpointerProcess, CheckpointerShmem, END_CRIT_SECTION, CheckpointerRequest::ftag, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), CheckpointerShmemStruct::num_requests, palloc(), pfree(), RememberSyncRequest(), CheckpointerShmemStruct::requests, START_CRIT_SECTION, and CheckpointerRequest::type.

Referenced by CheckpointerMain(), CheckpointWriteDelay(), CreateCheckPoint(), ProcessSyncRequests(), SyncPostCheckpoint(), and SyncPreCheckpoint().

◆ BackgroundWriterMain()

void BackgroundWriterMain ( char *  startup_data,
size_t  startup_data_len 
)

Definition at line 87 of file bgwriter.c.

88{
89 sigjmp_buf local_sigjmp_buf;
90 MemoryContext bgwriter_context;
91 bool prev_hibernate;
92 WritebackContext wb_context;
93
94 Assert(startup_data_len == 0);
95
98
99 /*
100 * Properly accept or ignore signals that might be sent to us.
101 */
103 pqsignal(SIGINT, SIG_IGN);
105 /* SIGQUIT handler was already set up by InitPostmasterChild */
106 pqsignal(SIGALRM, SIG_IGN);
107 pqsignal(SIGPIPE, SIG_IGN);
109 pqsignal(SIGUSR2, SIG_IGN);
110
111 /*
112 * Reset some signals that are accepted by postmaster but not here
113 */
114 pqsignal(SIGCHLD, SIG_DFL);
115
116 /*
117 * We just started, assume there has been either a shutdown or
118 * end-of-recovery snapshot.
119 */
121
122 /*
123 * Create a memory context that we will do all our work in. We do this so
124 * that we can reset the context during error recovery and thereby avoid
125 * possible memory leaks. Formerly this code just ran in
126 * TopMemoryContext, but resetting that would be a really bad idea.
127 */
128 bgwriter_context = AllocSetContextCreate(TopMemoryContext,
129 "Background Writer",
131 MemoryContextSwitchTo(bgwriter_context);
132
134
135 /*
136 * If an exception is encountered, processing resumes here.
137 *
138 * You might wonder why this isn't coded as an infinite loop around a
139 * PG_TRY construct. The reason is that this is the bottom of the
140 * exception stack, and so with PG_TRY there would be no exception handler
141 * in force at all during the CATCH part. By leaving the outermost setjmp
142 * always active, we have at least some chance of recovering from an error
143 * during error recovery. (If we get into an infinite loop thereby, it
144 * will soon be stopped by overflow of elog.c's internal state stack.)
145 *
146 * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask
147 * (to wit, BlockSig) will be restored when longjmp'ing to here. Thus,
148 * signals other than SIGQUIT will be blocked until we complete error
149 * recovery. It might seem that this policy makes the HOLD_INTERRUPTS()
150 * call redundant, but it is not since InterruptPending might be set
151 * already.
152 */
153 if (sigsetjmp(local_sigjmp_buf, 1) != 0)
154 {
155 /* Since not using PG_TRY, must reset error stack by hand */
156 error_context_stack = NULL;
157
158 /* Prevent interrupts while cleaning up */
160
161 /* Report the error to the server log */
163
164 /*
165 * These operations are really just a minimal subset of
166 * AbortTransaction(). We don't have very many resources to worry
167 * about in bgwriter, but we do have LWLocks, buffers, and temp files.
168 */
173 AtEOXact_Buffers(false);
175 AtEOXact_Files(false);
176 AtEOXact_HashTables(false);
177
178 /*
179 * Now return to normal top-level context and clear ErrorContext for
180 * next time.
181 */
182 MemoryContextSwitchTo(bgwriter_context);
184
185 /* Flush any leaked data in the top-level context */
186 MemoryContextReset(bgwriter_context);
187
188 /* re-initialize to avoid repeated errors causing problems */
190
191 /* Now we can allow interrupts again */
193
194 /*
195 * Sleep at least 1 second after any error. A write error is likely
196 * to be repeated, and we don't want to be filling the error logs as
197 * fast as we can.
198 */
199 pg_usleep(1000000L);
200
201 /* Report wait end here, when there is no further possibility of wait */
203 }
204
205 /* We can now handle ereport(ERROR) */
206 PG_exception_stack = &local_sigjmp_buf;
207
208 /*
209 * Unblock signals (they were blocked when the postmaster forked us)
210 */
211 sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
212
213 /*
214 * Reset hibernation state after any error.
215 */
216 prev_hibernate = false;
217
218 /*
219 * Loop forever
220 */
221 for (;;)
222 {
223 bool can_hibernate;
224 int rc;
225
226 /* Clear any already-pending wakeups */
228
230
231 /*
232 * Do one cycle of dirty-buffer writing.
233 */
234 can_hibernate = BgBufferSync(&wb_context);
235
236 /* Report pending statistics to the cumulative stats system */
238 pgstat_report_wal(true);
239
241 {
242 /*
243 * After any checkpoint, free all smgr objects. Otherwise we
244 * would never do so for dropped relations, as the bgwriter does
245 * not process shared invalidation messages or call
246 * AtEOXact_SMgr().
247 */
249 }
250
251 /*
252 * Log a new xl_running_xacts every now and then so replication can
253 * get into a consistent state faster (think of suboverflowed
254 * snapshots) and clean up resources (locks, KnownXids*) more
255 * frequently. The costs of this are relatively low, so doing it 4
256 * times (LOG_SNAPSHOT_INTERVAL_MS) a minute seems fine.
257 *
258 * We assume the interval for writing xl_running_xacts is
259 * significantly bigger than BgWriterDelay, so we don't complicate the
260 * overall timeout handling but just assume we're going to get called
261 * often enough even if hibernation mode is active. It's not that
262 * important that LOG_SNAPSHOT_INTERVAL_MS is met strictly. To make
263 * sure we're not waking the disk up unnecessarily on an idle system
264 * we check whether there has been any WAL inserted since the last
265 * time we've logged a running xacts.
266 *
267 * We do this logging in the bgwriter as it is the only process that
268 * is run regularly and returns to its mainloop all the time. E.g.
269 * Checkpointer, when active, is barely ever in its mainloop and thus
270 * makes it hard to log regularly.
271 */
273 {
274 TimestampTz timeout = 0;
276
279
280 /*
281 * Only log if enough time has passed and interesting records have
282 * been inserted since the last snapshot. Have to compare with <=
283 * instead of < because GetLastImportantRecPtr() points at the
284 * start of a record, whereas last_snapshot_lsn points just past
285 * the end of the record.
286 */
287 if (now >= timeout &&
289 {
292 }
293 }
294
295 /*
296 * Sleep until we are signaled or BgWriterDelay has elapsed.
297 *
298 * Note: the feedback control loop in BgBufferSync() expects that we
299 * will call it every BgWriterDelay msec. While it's not critical for
300 * correctness that that be exact, the feedback loop might misbehave
301 * if we stray too far from that. Hence, avoid loading this process
302 * down with latch events that are likely to happen frequently during
303 * normal operation.
304 */
305 rc = WaitLatch(MyLatch,
307 BgWriterDelay /* ms */ , WAIT_EVENT_BGWRITER_MAIN);
308
309 /*
310 * If no latch event and BgBufferSync says nothing's happening, extend
311 * the sleep in "hibernation" mode, where we sleep for much longer
312 * than bgwriter_delay says. Fewer wakeups save electricity. When a
313 * backend starts using buffers again, it will wake us up by setting
314 * our latch. Because the extra sleep will persist only as long as no
315 * buffer allocations happen, this should not distort the behavior of
316 * BgBufferSync's control loop too badly; essentially, it will think
317 * that the system-wide idle interval didn't exist.
318 *
319 * There is a race condition here, in that a backend might allocate a
320 * buffer between the time BgBufferSync saw the alloc count as zero
321 * and the time we call StrategyNotifyBgWriter. While it's not
322 * critical that we not hibernate anyway, we try to reduce the odds of
323 * that by only hibernating when BgBufferSync says nothing's happening
324 * for two consecutive cycles. Also, we mitigate any possible
325 * consequences of a missed wakeup by not hibernating forever.
326 */
327 if (rc == WL_TIMEOUT && can_hibernate && prev_hibernate)
328 {
329 /* Ask for notification at next buffer allocation */
331 /* Sleep ... */
332 (void) WaitLatch(MyLatch,
335 WAIT_EVENT_BGWRITER_HIBERNATE);
336 /* Reset the notification request in case we timed out */
338 }
339
340 prev_hibernate = can_hibernate;
341 }
342}
void AuxiliaryProcessMainCommon(void)
Definition: auxprocess.c:39
sigset_t UnBlockSig
Definition: pqsignal.c:22
TimestampTz GetCurrentTimestamp(void)
Definition: timestamp.c:1644
Datum now(PG_FUNCTION_ARGS)
Definition: timestamp.c:1608
static XLogRecPtr last_snapshot_lsn
Definition: bgwriter.c:77
static TimestampTz last_snapshot_ts
Definition: bgwriter.c:76
int BgWriterDelay
Definition: bgwriter.c:57
#define HIBERNATE_FACTOR
Definition: bgwriter.c:63
#define LOG_SNAPSHOT_INTERVAL_MS
Definition: bgwriter.c:69
void AtEOXact_Buffers(bool isCommit)
Definition: bufmgr.c:3559
bool BgBufferSync(WritebackContext *wb_context)
Definition: bufmgr.c:3188
void UnlockBuffers(void)
Definition: bufmgr.c:5072
int bgwriter_flush_after
Definition: bufmgr.c:172
void WritebackContextInit(WritebackContext *context, int *max_pending)
Definition: bufmgr.c:5845
#define Assert(condition)
Definition: c.h:815
bool FirstCallSinceLastCheckpoint(void)
bool ConditionVariableCancelSleep(void)
int64 TimestampTz
Definition: timestamp.h:39
void AtEOXact_HashTables(bool isCommit)
Definition: dynahash.c:1912
void EmitErrorReport(void)
Definition: elog.c:1687
ErrorContextCallback * error_context_stack
Definition: elog.c:94
void FlushErrorState(void)
Definition: elog.c:1867
sigjmp_buf * PG_exception_stack
Definition: elog.c:96
void AtEOXact_Files(bool isCommit)
Definition: fd.c:3187
void StrategyNotifyBgWriter(int bgwprocno)
Definition: freelist.c:431
ProcNumber MyProcNumber
Definition: globals.c:89
struct Latch * MyLatch
Definition: globals.c:62
void SignalHandlerForShutdownRequest(SIGNAL_ARGS)
Definition: interrupt.c:105
void SignalHandlerForConfigReload(SIGNAL_ARGS)
Definition: interrupt.c:61
void HandleMainLoopInterrupts(void)
Definition: interrupt.c:34
void ResetLatch(Latch *latch)
Definition: latch.c:724
int WaitLatch(Latch *latch, int wakeEvents, long timeout, uint32 wait_event_info)
Definition: latch.c:517
#define WL_TIMEOUT
Definition: latch.h:130
#define WL_EXIT_ON_PM_DEATH
Definition: latch.h:132
#define WL_LATCH_SET
Definition: latch.h:127
void LWLockReleaseAll(void)
Definition: lwlock.c:1876
void MemoryContextReset(MemoryContext context)
Definition: mcxt.c:383
MemoryContext TopMemoryContext
Definition: mcxt.c:149
#define AllocSetContextCreate
Definition: memutils.h:129
#define ALLOCSET_DEFAULT_SIZES
Definition: memutils.h:160
#define RESUME_INTERRUPTS()
Definition: miscadmin.h:135
#define HOLD_INTERRUPTS()
Definition: miscadmin.h:133
@ B_BG_WRITER
Definition: miscadmin.h:361
BackendType MyBackendType
Definition: miscinit.c:64
static MemoryContext MemoryContextSwitchTo(MemoryContext context)
Definition: palloc.h:124
void pgstat_report_bgwriter(void)
void pgstat_report_wal(bool force)
Definition: pgstat_wal.c:48
#define pqsignal
Definition: port.h:520
void procsignal_sigusr1_handler(SIGNAL_ARGS)
Definition: procsignal.c:671
void ReleaseAuxProcessResources(bool isCommit)
Definition: resowner.c:1002
void pg_usleep(long microsec)
Definition: signal.c:53
void smgrdestroyall(void)
Definition: smgr.c:335
void AtEOXact_SMgr(void)
Definition: smgr.c:835
XLogRecPtr LogStandbySnapshot(void)
Definition: standby.c:1281
#define TimestampTzPlusMilliseconds(tz, ms)
Definition: timestamp.h:85
static void pgstat_report_wait_end(void)
Definition: wait_event.h:101
#define SIGCHLD
Definition: win32_port.h:168
#define SIGHUP
Definition: win32_port.h:158
#define SIGPIPE
Definition: win32_port.h:163
#define SIGUSR1
Definition: win32_port.h:170
#define SIGALRM
Definition: win32_port.h:164
#define SIGUSR2
Definition: win32_port.h:171
bool RecoveryInProgress(void)
Definition: xlog.c:6334
XLogRecPtr GetLastImportantRecPtr(void)
Definition: xlog.c:6556
#define XLogStandbyInfoActive()
Definition: xlog.h:123

References ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, Assert, AtEOXact_Buffers(), AtEOXact_Files(), AtEOXact_HashTables(), AtEOXact_SMgr(), AuxiliaryProcessMainCommon(), B_BG_WRITER, BgBufferSync(), bgwriter_flush_after, BgWriterDelay, ConditionVariableCancelSleep(), EmitErrorReport(), error_context_stack, FirstCallSinceLastCheckpoint(), FlushErrorState(), GetCurrentTimestamp(), GetLastImportantRecPtr(), HandleMainLoopInterrupts(), HIBERNATE_FACTOR, HOLD_INTERRUPTS, last_snapshot_lsn, last_snapshot_ts, LOG_SNAPSHOT_INTERVAL_MS, LogStandbySnapshot(), LWLockReleaseAll(), MemoryContextReset(), MemoryContextSwitchTo(), MyBackendType, MyLatch, MyProcNumber, now(), PG_exception_stack, pg_usleep(), pgstat_report_bgwriter(), pgstat_report_wait_end(), pgstat_report_wal(), pqsignal, procsignal_sigusr1_handler(), RecoveryInProgress(), ReleaseAuxProcessResources(), ResetLatch(), RESUME_INTERRUPTS, SIGALRM, SIGCHLD, SIGHUP, SignalHandlerForConfigReload(), SignalHandlerForShutdownRequest(), SIGPIPE, SIGUSR1, SIGUSR2, smgrdestroyall(), StrategyNotifyBgWriter(), TimestampTzPlusMilliseconds, TopMemoryContext, UnBlockSig, UnlockBuffers(), WaitLatch(), WL_EXIT_ON_PM_DEATH, WL_LATCH_SET, WL_TIMEOUT, WritebackContextInit(), and XLogStandbyInfoActive.

◆ CheckpointerMain()

void CheckpointerMain ( char *  startup_data,
size_t  startup_data_len 
)

Definition at line 173 of file checkpointer.c.

174{
175 sigjmp_buf local_sigjmp_buf;
176 MemoryContext checkpointer_context;
177
178 Assert(startup_data_len == 0);
179
182
184
185 /*
186 * Properly accept or ignore signals the postmaster might send us
187 *
188 * Note: we deliberately ignore SIGTERM, because during a standard Unix
189 * system shutdown cycle, init will SIGTERM all processes at once. We
190 * want to wait for the backends to exit, whereupon the postmaster will
191 * tell us it's okay to shut down (via SIGUSR2).
192 */
194 pqsignal(SIGINT, ReqCheckpointHandler); /* request checkpoint */
195 pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */
196 /* SIGQUIT handler was already set up by InitPostmasterChild */
197 pqsignal(SIGALRM, SIG_IGN);
198 pqsignal(SIGPIPE, SIG_IGN);
201
202 /*
203 * Reset some signals that are accepted by postmaster but not here
204 */
205 pqsignal(SIGCHLD, SIG_DFL);
206
207 /*
208 * Initialize so that first time-driven event happens at the correct time.
209 */
211
212 /*
213 * Write out stats after shutdown. This needs to be called by exactly one
214 * process during a normal shutdown, and since checkpointer is shut down
215 * very late...
216 *
217 * Walsenders are shut down after the checkpointer, but currently don't
218 * report stats. If that changes, we need a more complicated solution.
219 */
221
222 /*
223 * Create a memory context that we will do all our work in. We do this so
224 * that we can reset the context during error recovery and thereby avoid
225 * possible memory leaks. Formerly this code just ran in
226 * TopMemoryContext, but resetting that would be a really bad idea.
227 */
228 checkpointer_context = AllocSetContextCreate(TopMemoryContext,
229 "Checkpointer",
231 MemoryContextSwitchTo(checkpointer_context);
232
233 /*
234 * If an exception is encountered, processing resumes here.
235 *
236 * You might wonder why this isn't coded as an infinite loop around a
237 * PG_TRY construct. The reason is that this is the bottom of the
238 * exception stack, and so with PG_TRY there would be no exception handler
239 * in force at all during the CATCH part. By leaving the outermost setjmp
240 * always active, we have at least some chance of recovering from an error
241 * during error recovery. (If we get into an infinite loop thereby, it
242 * will soon be stopped by overflow of elog.c's internal state stack.)
243 *
244 * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask
245 * (to wit, BlockSig) will be restored when longjmp'ing to here. Thus,
246 * signals other than SIGQUIT will be blocked until we complete error
247 * recovery. It might seem that this policy makes the HOLD_INTERRUPTS()
248 * call redundant, but it is not since InterruptPending might be set
249 * already.
250 */
251 if (sigsetjmp(local_sigjmp_buf, 1) != 0)
252 {
253 /* Since not using PG_TRY, must reset error stack by hand */
254 error_context_stack = NULL;
255
256 /* Prevent interrupts while cleaning up */
258
259 /* Report the error to the server log */
261
262 /*
263 * These operations are really just a minimal subset of
264 * AbortTransaction(). We don't have very many resources to worry
265 * about in checkpointer, but we do have LWLocks, buffers, and temp
266 * files.
267 */
273 AtEOXact_Buffers(false);
275 AtEOXact_Files(false);
276 AtEOXact_HashTables(false);
277
278 /* Warn any waiting backends that the checkpoint failed. */
279 if (ckpt_active)
280 {
285
287
288 ckpt_active = false;
289 }
290
291 /*
292 * Now return to normal top-level context and clear ErrorContext for
293 * next time.
294 */
295 MemoryContextSwitchTo(checkpointer_context);
297
298 /* Flush any leaked data in the top-level context */
299 MemoryContextReset(checkpointer_context);
300
301 /* Now we can allow interrupts again */
303
304 /*
305 * Sleep at least 1 second after any error. A write error is likely
306 * to be repeated, and we don't want to be filling the error logs as
307 * fast as we can.
308 */
309 pg_usleep(1000000L);
310 }
311
312 /* We can now handle ereport(ERROR) */
313 PG_exception_stack = &local_sigjmp_buf;
314
315 /*
316 * Unblock signals (they were blocked when the postmaster forked us)
317 */
318 sigprocmask(SIG_SETMASK, &UnBlockSig, NULL);
319
320 /*
321 * Ensure all shared memory values are set correctly for the config. Doing
322 * this here ensures no race conditions from other concurrent updaters.
323 */
325
326 /*
327 * Advertise our proc number that backends can use to wake us up while
328 * we're sleeping.
329 */
331
332 /*
333 * Loop forever
334 */
335 for (;;)
336 {
337 bool do_checkpoint = false;
338 int flags = 0;
340 int elapsed_secs;
341 int cur_timeout;
342 bool chkpt_or_rstpt_requested = false;
343 bool chkpt_or_rstpt_timed = false;
344
345 /* Clear any already-pending wakeups */
347
348 /*
349 * Process any requests or signals received recently.
350 */
353
354 /*
355 * Detect a pending checkpoint request by checking whether the flags
356 * word in shared memory is nonzero. We shouldn't need to acquire the
357 * ckpt_lck for this.
358 */
359 if (((volatile CheckpointerShmemStruct *) CheckpointerShmem)->ckpt_flags)
360 {
361 do_checkpoint = true;
362 chkpt_or_rstpt_requested = true;
363 }
364
365 /*
366 * Force a checkpoint if too much time has elapsed since the last one.
367 * Note that we count a timed checkpoint in stats only when this
368 * occurs without an external request, but we set the CAUSE_TIME flag
369 * bit even if there is also an external request.
370 */
371 now = (pg_time_t) time(NULL);
372 elapsed_secs = now - last_checkpoint_time;
373 if (elapsed_secs >= CheckPointTimeout)
374 {
375 if (!do_checkpoint)
376 chkpt_or_rstpt_timed = true;
377 do_checkpoint = true;
378 flags |= CHECKPOINT_CAUSE_TIME;
379 }
380
381 /*
382 * Do a checkpoint if requested.
383 */
384 if (do_checkpoint)
385 {
386 bool ckpt_performed = false;
387 bool do_restartpoint;
388
389 /* Check if we should perform a checkpoint or a restartpoint. */
390 do_restartpoint = RecoveryInProgress();
391
392 /*
393 * Atomically fetch the request flags to figure out what kind of a
394 * checkpoint we should perform, and increase the started-counter
395 * to acknowledge that we've started a new checkpoint.
396 */
402
404
405 /*
406 * The end-of-recovery checkpoint is a real checkpoint that's
407 * performed while we're still in recovery.
408 */
409 if (flags & CHECKPOINT_END_OF_RECOVERY)
410 do_restartpoint = false;
411
412 if (chkpt_or_rstpt_timed)
413 {
414 chkpt_or_rstpt_timed = false;
415 if (do_restartpoint)
417 else
419 }
420
421 if (chkpt_or_rstpt_requested)
422 {
423 chkpt_or_rstpt_requested = false;
424 if (do_restartpoint)
426 else
428 }
429
430 /*
431 * We will warn if (a) too soon since last checkpoint (whatever
432 * caused it) and (b) somebody set the CHECKPOINT_CAUSE_XLOG flag
433 * since the last checkpoint start. Note in particular that this
434 * implementation will not generate warnings caused by
435 * CheckPointTimeout < CheckPointWarning.
436 */
437 if (!do_restartpoint &&
438 (flags & CHECKPOINT_CAUSE_XLOG) &&
439 elapsed_secs < CheckPointWarning)
440 ereport(LOG,
441 (errmsg_plural("checkpoints are occurring too frequently (%d second apart)",
442 "checkpoints are occurring too frequently (%d seconds apart)",
443 elapsed_secs,
444 elapsed_secs),
445 errhint("Consider increasing the configuration parameter \"%s\".", "max_wal_size")));
446
447 /*
448 * Initialize checkpointer-private variables used during
449 * checkpoint.
450 */
451 ckpt_active = true;
452 if (do_restartpoint)
454 else
458
459 /*
460 * Do the checkpoint.
461 */
462 if (!do_restartpoint)
463 ckpt_performed = CreateCheckPoint(flags);
464 else
465 ckpt_performed = CreateRestartPoint(flags);
466
467 /*
468 * After any checkpoint, free all smgr objects. Otherwise we
469 * would never do so for dropped relations, as the checkpointer
470 * does not process shared invalidation messages or call
471 * AtEOXact_SMgr().
472 */
474
475 /*
476 * Indicate checkpoint completion to any waiting backends.
477 */
481
483
484 if (!do_restartpoint)
485 {
486 /*
487 * Note we record the checkpoint start time not end time as
488 * last_checkpoint_time. This is so that time-driven
489 * checkpoints happen at a predictable spacing.
490 */
492
493 if (ckpt_performed)
495 }
496 else
497 {
498 if (ckpt_performed)
499 {
500 /*
501 * The same as for checkpoint. Please see the
502 * corresponding comment.
503 */
505
507 }
508 else
509 {
510 /*
511 * We were not able to perform the restartpoint
512 * (checkpoints throw an ERROR in case of error). Most
513 * likely because we have not received any new checkpoint
514 * WAL records since the last restartpoint. Try again in
515 * 15 s.
516 */
518 }
519 }
520
521 ckpt_active = false;
522
523 /* We may have received an interrupt during the checkpoint. */
525 }
526
527 /* Check for archive_timeout and switch xlog files if necessary. */
529
530 /* Report pending statistics to the cumulative stats system */
532 pgstat_report_wal(true);
533
534 /*
535 * If any checkpoint flags have been set, redo the loop to handle the
536 * checkpoint without sleeping.
537 */
538 if (((volatile CheckpointerShmemStruct *) CheckpointerShmem)->ckpt_flags)
539 continue;
540
541 /*
542 * Sleep until we are signaled or it's time for another checkpoint or
543 * xlog file switch.
544 */
545 now = (pg_time_t) time(NULL);
546 elapsed_secs = now - last_checkpoint_time;
547 if (elapsed_secs >= CheckPointTimeout)
548 continue; /* no sleep for us ... */
549 cur_timeout = CheckPointTimeout - elapsed_secs;
551 {
552 elapsed_secs = now - last_xlog_switch_time;
553 if (elapsed_secs >= XLogArchiveTimeout)
554 continue; /* no sleep for us ... */
555 cur_timeout = Min(cur_timeout, XLogArchiveTimeout - elapsed_secs);
556 }
557
558 (void) WaitLatch(MyLatch,
560 cur_timeout * 1000L /* convert to ms */ ,
561 WAIT_EVENT_CHECKPOINTER_MAIN);
562 }
563}
#define Min(x, y)
Definition: c.h:961
static void UpdateSharedMemoryConfig(void)
static XLogRecPtr ckpt_start_recptr
Definition: checkpointer.c:147
static void ReqCheckpointHandler(SIGNAL_ARGS)
Definition: checkpointer.c:870
static void CheckArchiveTimeout(void)
Definition: checkpointer.c:634
static double ckpt_cached_elapsed
Definition: checkpointer.c:148
static bool ckpt_active
Definition: checkpointer.c:143
static void HandleCheckpointerInterrupts(void)
Definition: checkpointer.c:569
void AbsorbSyncRequests(void)
static pg_time_t last_xlog_switch_time
Definition: checkpointer.c:151
int CheckPointWarning
Definition: checkpointer.c:137
int CheckPointTimeout
Definition: checkpointer.c:136
static pg_time_t last_checkpoint_time
Definition: checkpointer.c:150
static pg_time_t ckpt_start_time
Definition: checkpointer.c:146
void ConditionVariableBroadcast(ConditionVariable *cv)
int errmsg_plural(const char *fmt_singular, const char *fmt_plural, unsigned long n,...)
Definition: elog.c:1180
int errhint(const char *fmt,...)
Definition: elog.c:1317
#define LOG
Definition: elog.h:31
#define ereport(elevel,...)
Definition: elog.h:149
int MyProcPid
Definition: globals.c:46
void before_shmem_exit(pg_on_exit_callback function, Datum arg)
Definition: ipc.c:337
@ B_CHECKPOINTER
Definition: miscadmin.h:362
void pgstat_before_server_shutdown(int code, Datum arg)
Definition: pgstat.c:560
void pgstat_report_checkpointer(void)
PgStat_CheckpointerStats PendingCheckpointerStats
int64 pg_time_t
Definition: pgtime.h:23
#define SpinLockRelease(lock)
Definition: spin.h:61
#define SpinLockAcquire(lock)
Definition: spin.h:59
PROC_HDR * ProcGlobal
Definition: proc.c:78
ConditionVariable done_cv
Definition: checkpointer.c:121
ConditionVariable start_cv
Definition: checkpointer.c:120
ProcNumber checkpointerProc
Definition: proc.h:408
PgStat_Counter restartpoints_requested
Definition: pgstat.h:260
PgStat_Counter num_requested
Definition: pgstat.h:257
PgStat_Counter num_performed
Definition: pgstat.h:258
PgStat_Counter restartpoints_timed
Definition: pgstat.h:259
PgStat_Counter num_timed
Definition: pgstat.h:256
PgStat_Counter restartpoints_performed
Definition: pgstat.h:261
bool CreateRestartPoint(int flags)
Definition: xlog.c:7591
XLogRecPtr GetInsertRecPtr(void)
Definition: xlog.c:6482
int XLogArchiveTimeout
Definition: xlog.c:118
bool CreateCheckPoint(int flags)
Definition: xlog.c:6889
#define CHECKPOINT_CAUSE_XLOG
Definition: xlog.h:148
#define CHECKPOINT_END_OF_RECOVERY
Definition: xlog.h:140
#define CHECKPOINT_CAUSE_TIME
Definition: xlog.h:149
XLogRecPtr GetXLogReplayRecPtr(TimeLineID *replayTLI)

References AbsorbSyncRequests(), ALLOCSET_DEFAULT_SIZES, AllocSetContextCreate, Assert, AtEOXact_Buffers(), AtEOXact_Files(), AtEOXact_HashTables(), AtEOXact_SMgr(), AuxiliaryProcessMainCommon(), B_CHECKPOINTER, before_shmem_exit(), CheckArchiveTimeout(), CHECKPOINT_CAUSE_TIME, CHECKPOINT_CAUSE_XLOG, CHECKPOINT_END_OF_RECOVERY, CheckpointerShmemStruct::checkpointer_pid, PROC_HDR::checkpointerProc, CheckpointerShmem, CheckPointTimeout, CheckPointWarning, ckpt_active, ckpt_cached_elapsed, CheckpointerShmemStruct::ckpt_done, CheckpointerShmemStruct::ckpt_failed, CheckpointerShmemStruct::ckpt_flags, CheckpointerShmemStruct::ckpt_lck, ckpt_start_recptr, ckpt_start_time, CheckpointerShmemStruct::ckpt_started, ConditionVariableBroadcast(), ConditionVariableCancelSleep(), CreateCheckPoint(), CreateRestartPoint(), CheckpointerShmemStruct::done_cv, EmitErrorReport(), ereport, errhint(), errmsg_plural(), error_context_stack, FlushErrorState(), GetInsertRecPtr(), GetXLogReplayRecPtr(), HandleCheckpointerInterrupts(), HOLD_INTERRUPTS, last_checkpoint_time, last_xlog_switch_time, LOG, LWLockReleaseAll(), MemoryContextReset(), MemoryContextSwitchTo(), Min, MyBackendType, MyLatch, MyProcNumber, MyProcPid, now(), PgStat_CheckpointerStats::num_performed, PgStat_CheckpointerStats::num_requested, PgStat_CheckpointerStats::num_timed, PendingCheckpointerStats, PG_exception_stack, pg_usleep(), pgstat_before_server_shutdown(), pgstat_report_checkpointer(), pgstat_report_wait_end(), pgstat_report_wal(), pqsignal, ProcGlobal, procsignal_sigusr1_handler(), RecoveryInProgress(), ReleaseAuxProcessResources(), ReqCheckpointHandler(), ResetLatch(), PgStat_CheckpointerStats::restartpoints_performed, PgStat_CheckpointerStats::restartpoints_requested, PgStat_CheckpointerStats::restartpoints_timed, RESUME_INTERRUPTS, SIGALRM, SIGCHLD, SIGHUP, SignalHandlerForConfigReload(), SignalHandlerForShutdownRequest(), SIGPIPE, SIGUSR1, SIGUSR2, smgrdestroyall(), SpinLockAcquire, SpinLockRelease, CheckpointerShmemStruct::start_cv, TopMemoryContext, UnBlockSig, UnlockBuffers(), UpdateSharedMemoryConfig(), WaitLatch(), WL_EXIT_ON_PM_DEATH, WL_LATCH_SET, WL_TIMEOUT, and XLogArchiveTimeout.

◆ CheckpointerShmemInit()

void CheckpointerShmemInit ( void  )

Definition at line 909 of file checkpointer.c.

910{
912 bool found;
913
915 ShmemInitStruct("Checkpointer Data",
916 size,
917 &found);
918
919 if (!found)
920 {
921 /*
922 * First time through, so initialize. Note that we zero the whole
923 * requests array; this is so that CompactCheckpointerRequestQueue can
924 * assume that any pad bytes in the request structs are zeroes.
925 */
931 }
932}
#define MemSet(start, val, len)
Definition: c.h:977
size_t Size
Definition: c.h:562
Size CheckpointerShmemSize(void)
Definition: checkpointer.c:890
void ConditionVariableInit(ConditionVariable *cv)
int NBuffers
Definition: globals.c:141
void * ShmemInitStruct(const char *name, Size size, bool *foundPtr)
Definition: shmem.c:382
static pg_noinline void Size size
Definition: slab.c:607
#define SpinLockInit(lock)
Definition: spin.h:57

References CheckpointerShmem, CheckpointerShmemSize(), CheckpointerShmemStruct::ckpt_lck, ConditionVariableInit(), CheckpointerShmemStruct::done_cv, CheckpointerShmemStruct::max_requests, MemSet, NBuffers, ShmemInitStruct(), size, SpinLockInit, and CheckpointerShmemStruct::start_cv.

Referenced by CreateOrAttachShmemStructs().

◆ CheckpointerShmemSize()

Size CheckpointerShmemSize ( void  )

Definition at line 890 of file checkpointer.c.

891{
892 Size size;
893
894 /*
895 * Currently, the size of the requests[] array is arbitrarily set equal to
896 * NBuffers. This may prove too large or small ...
897 */
898 size = offsetof(CheckpointerShmemStruct, requests);
900
901 return size;
902}
Size add_size(Size s1, Size s2)
Definition: shmem.c:488
Size mul_size(Size s1, Size s2)
Definition: shmem.c:505

References add_size(), mul_size(), NBuffers, and size.

Referenced by CalculateShmemSize(), and CheckpointerShmemInit().

◆ CheckpointWriteDelay()

void CheckpointWriteDelay ( int  flags,
double  progress 
)

Definition at line 722 of file checkpointer.c.

723{
724 static int absorb_counter = WRITES_PER_ABSORB;
725
726 /* Do nothing if checkpoint is being executed by non-checkpointer process */
728 return;
729
730 /*
731 * Perform the usual duties and take a nap, unless we're behind schedule,
732 * in which case we just try to catch up as quickly as possible.
733 */
734 if (!(flags & CHECKPOINT_IMMEDIATE) &&
738 {
740 {
741 ConfigReloadPending = false;
743 /* update shmem copies of config variables */
745 }
746
748 absorb_counter = WRITES_PER_ABSORB;
749
751
752 /* Report interim statistics to the cumulative stats system */
754
755 /*
756 * This sleep used to be connected to bgwriter_delay, typically 200ms.
757 * That resulted in more frequent wakeups if not much work to do.
758 * Checkpointer and bgwriter are no longer related so take the Big
759 * Sleep.
760 */
762 100,
763 WAIT_EVENT_CHECKPOINT_WRITE_DELAY);
765 }
766 else if (--absorb_counter <= 0)
767 {
768 /*
769 * Absorb pending fsync requests after each WRITES_PER_ABSORB write
770 * operations even when we don't sleep, to prevent overflow of the
771 * fsync request queue.
772 */
774 absorb_counter = WRITES_PER_ABSORB;
775 }
776
777 /* Check for barrier events. */
780}
static bool ImmediateCheckpointRequested(void)
Definition: checkpointer.c:695
static bool IsCheckpointOnSchedule(double progress)
Definition: checkpointer.c:791
#define WRITES_PER_ABSORB
Definition: checkpointer.c:131
volatile sig_atomic_t ProcSignalBarrierPending
Definition: globals.c:39
void ProcessConfigFile(GucContext context)
Definition: guc-file.l:120
@ PGC_SIGHUP
Definition: guc.h:71
volatile sig_atomic_t ShutdownRequestPending
Definition: interrupt.c:28
volatile sig_atomic_t ConfigReloadPending
Definition: interrupt.c:27
static int progress
Definition: pgbench.c:261
void ProcessProcSignalBarrier(void)
Definition: procsignal.c:496
#define CHECKPOINT_IMMEDIATE
Definition: xlog.h:141

References AbsorbSyncRequests(), AmCheckpointerProcess, CheckArchiveTimeout(), CHECKPOINT_IMMEDIATE, ConfigReloadPending, ImmediateCheckpointRequested(), IsCheckpointOnSchedule(), MyLatch, PGC_SIGHUP, pgstat_report_checkpointer(), ProcessConfigFile(), ProcessProcSignalBarrier(), ProcSignalBarrierPending, progress, ResetLatch(), ShutdownRequestPending, UpdateSharedMemoryConfig(), WaitLatch(), WL_EXIT_ON_PM_DEATH, WL_LATCH_SET, WL_TIMEOUT, and WRITES_PER_ABSORB.

Referenced by BufferSync().

◆ FirstCallSinceLastCheckpoint()

bool FirstCallSinceLastCheckpoint ( void  )

Definition at line 1347 of file checkpointer.c.

1348{
1349 static int ckpt_done = 0;
1350 int new_done;
1351 bool FirstCall = false;
1352
1354 new_done = CheckpointerShmem->ckpt_done;
1356
1357 if (new_done != ckpt_done)
1358 FirstCall = true;
1359
1360 ckpt_done = new_done;
1361
1362 return FirstCall;
1363}

References CheckpointerShmem, CheckpointerShmemStruct::ckpt_done, CheckpointerShmemStruct::ckpt_lck, SpinLockAcquire, and SpinLockRelease.

Referenced by BackgroundWriterMain().

◆ ForwardSyncRequest()

bool ForwardSyncRequest ( const FileTag ftag,
SyncRequestType  type 
)

Definition at line 1104 of file checkpointer.c.

1105{
1106 CheckpointerRequest *request;
1107 bool too_full;
1108
1109 if (!IsUnderPostmaster)
1110 return false; /* probably shouldn't even get here */
1111
1113 elog(ERROR, "ForwardSyncRequest must not be called in checkpointer");
1114
1115 LWLockAcquire(CheckpointerCommLock, LW_EXCLUSIVE);
1116
1117 /*
1118 * If the checkpointer isn't running or the request queue is full, the
1119 * backend will have to perform its own fsync request. But before forcing
1120 * that to happen, we can try to compact the request queue.
1121 */
1125 {
1126 LWLockRelease(CheckpointerCommLock);
1127 return false;
1128 }
1129
1130 /* OK, insert request */
1132 request->ftag = *ftag;
1133 request->type = type;
1134
1135 /* If queue is more than half full, nudge the checkpointer to empty it */
1136 too_full = (CheckpointerShmem->num_requests >=
1138
1139 LWLockRelease(CheckpointerCommLock);
1140
1141 /* ... but not till after we release the lock */
1142 if (too_full)
1143 {
1144 volatile PROC_HDR *procglobal = ProcGlobal;
1145 ProcNumber checkpointerProc = procglobal->checkpointerProc;
1146
1147 if (checkpointerProc != INVALID_PROC_NUMBER)
1148 SetLatch(&GetPGProcByNumber(checkpointerProc)->procLatch);
1149 }
1150
1151 return true;
1152}
static bool CompactCheckpointerRequestQueue(void)
#define ERROR
Definition: elog.h:39
#define elog(elevel,...)
Definition: elog.h:225
bool IsUnderPostmaster
Definition: globals.c:119
void SetLatch(Latch *latch)
Definition: latch.c:632
#define GetPGProcByNumber(n)
Definition: proc.h:423
#define INVALID_PROC_NUMBER
Definition: procnumber.h:26
int ProcNumber
Definition: procnumber.h:24
Definition: proc.h:369
const char * type

References AmCheckpointerProcess, CheckpointerShmemStruct::checkpointer_pid, PROC_HDR::checkpointerProc, CheckpointerShmem, CompactCheckpointerRequestQueue(), elog, ERROR, CheckpointerRequest::ftag, GetPGProcByNumber, INVALID_PROC_NUMBER, IsUnderPostmaster, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), CheckpointerShmemStruct::max_requests, CheckpointerShmemStruct::num_requests, ProcGlobal, CheckpointerShmemStruct::requests, SetLatch(), CheckpointerRequest::type, and type.

Referenced by RegisterSyncRequest().

◆ RequestCheckpoint()

void RequestCheckpoint ( int  flags)

Definition at line 952 of file checkpointer.c.

953{
954 int ntries;
955 int old_failed,
956 old_started;
957
958 /*
959 * If in a standalone backend, just do it ourselves.
960 */
962 {
963 /*
964 * There's no point in doing slow checkpoints in a standalone backend,
965 * because there's no other backends the checkpoint could disrupt.
966 */
968
969 /* Free all smgr objects, as CheckpointerMain() normally would. */
971
972 return;
973 }
974
975 /*
976 * Atomically set the request flags, and take a snapshot of the counters.
977 * When we see ckpt_started > old_started, we know the flags we set here
978 * have been seen by checkpointer.
979 *
980 * Note that we OR the flags with any existing flags, to avoid overriding
981 * a "stronger" request by another backend. The flag senses must be
982 * chosen to make this work!
983 */
985
986 old_failed = CheckpointerShmem->ckpt_failed;
987 old_started = CheckpointerShmem->ckpt_started;
989
991
992 /*
993 * Send signal to request checkpoint. It's possible that the checkpointer
994 * hasn't started yet, or is in process of restarting, so we will retry a
995 * few times if needed. (Actually, more than a few times, since on slow
996 * or overloaded buildfarm machines, it's been observed that the
997 * checkpointer can take several seconds to start.) However, if not told
998 * to wait for the checkpoint to occur, we consider failure to send the
999 * signal to be nonfatal and merely LOG it. The checkpointer should see
1000 * the request when it does start, with or without getting a signal.
1001 */
1002#define MAX_SIGNAL_TRIES 600 /* max wait 60.0 sec */
1003 for (ntries = 0;; ntries++)
1004 {
1006 {
1007 if (ntries >= MAX_SIGNAL_TRIES || !(flags & CHECKPOINT_WAIT))
1008 {
1009 elog((flags & CHECKPOINT_WAIT) ? ERROR : LOG,
1010 "could not signal for checkpoint: checkpointer is not running");
1011 break;
1012 }
1013 }
1014 else if (kill(CheckpointerShmem->checkpointer_pid, SIGINT) != 0)
1015 {
1016 if (ntries >= MAX_SIGNAL_TRIES || !(flags & CHECKPOINT_WAIT))
1017 {
1018 elog((flags & CHECKPOINT_WAIT) ? ERROR : LOG,
1019 "could not signal for checkpoint: %m");
1020 break;
1021 }
1022 }
1023 else
1024 break; /* signal sent successfully */
1025
1027 pg_usleep(100000L); /* wait 0.1 sec, then retry */
1028 }
1029
1030 /*
1031 * If requested, wait for completion. We detect completion according to
1032 * the algorithm given above.
1033 */
1034 if (flags & CHECKPOINT_WAIT)
1035 {
1036 int new_started,
1037 new_failed;
1038
1039 /* Wait for a new checkpoint to start. */
1041 for (;;)
1042 {
1044 new_started = CheckpointerShmem->ckpt_started;
1046
1047 if (new_started != old_started)
1048 break;
1049
1051 WAIT_EVENT_CHECKPOINT_START);
1052 }
1054
1055 /*
1056 * We are waiting for ckpt_done >= new_started, in a modulo sense.
1057 */
1059 for (;;)
1060 {
1061 int new_done;
1062
1064 new_done = CheckpointerShmem->ckpt_done;
1065 new_failed = CheckpointerShmem->ckpt_failed;
1067
1068 if (new_done - new_started >= 0)
1069 break;
1070
1072 WAIT_EVENT_CHECKPOINT_DONE);
1073 }
1075
1076 if (new_failed != old_failed)
1077 ereport(ERROR,
1078 (errmsg("checkpoint request failed"),
1079 errhint("Consult recent messages in the server log for details.")));
1080 }
1081}
#define MAX_SIGNAL_TRIES
void ConditionVariablePrepareToSleep(ConditionVariable *cv)
void ConditionVariableSleep(ConditionVariable *cv, uint32 wait_event_info)
int errmsg(const char *fmt,...)
Definition: elog.c:1070
bool IsPostmasterEnvironment
Definition: globals.c:118
#define CHECK_FOR_INTERRUPTS()
Definition: miscadmin.h:122
#define kill(pid, sig)
Definition: win32_port.h:493
#define CHECKPOINT_REQUESTED
Definition: xlog.h:146
#define CHECKPOINT_WAIT
Definition: xlog.h:145

References CHECK_FOR_INTERRUPTS, CHECKPOINT_IMMEDIATE, CHECKPOINT_REQUESTED, CHECKPOINT_WAIT, CheckpointerShmemStruct::checkpointer_pid, CheckpointerShmem, CheckpointerShmemStruct::ckpt_done, CheckpointerShmemStruct::ckpt_failed, CheckpointerShmemStruct::ckpt_flags, CheckpointerShmemStruct::ckpt_lck, CheckpointerShmemStruct::ckpt_started, ConditionVariableCancelSleep(), ConditionVariablePrepareToSleep(), ConditionVariableSleep(), CreateCheckPoint(), CheckpointerShmemStruct::done_cv, elog, ereport, errhint(), errmsg(), ERROR, IsPostmasterEnvironment, kill, LOG, MAX_SIGNAL_TRIES, pg_usleep(), smgrdestroyall(), SpinLockAcquire, SpinLockRelease, and CheckpointerShmemStruct::start_cv.

Referenced by CreateDatabaseUsingFileCopy(), do_pg_backup_start(), dropdb(), DropTableSpace(), movedb(), PerformRecoveryXLogAction(), standard_ProcessUtility(), StartupXLOG(), XLogPageRead(), and XLogWrite().

Variable Documentation

◆ BgWriterDelay

PGDLLIMPORT int BgWriterDelay
extern

Definition at line 57 of file bgwriter.c.

Referenced by BackgroundWriterMain(), and BgBufferSync().

◆ CheckPointCompletionTarget

PGDLLIMPORT double CheckPointCompletionTarget
extern

◆ CheckPointTimeout

PGDLLIMPORT int CheckPointTimeout
extern

Definition at line 136 of file checkpointer.c.

Referenced by CheckpointerMain(), and IsCheckpointOnSchedule().

◆ CheckPointWarning

PGDLLIMPORT int CheckPointWarning
extern

Definition at line 137 of file checkpointer.c.

Referenced by CheckpointerMain().