From 82a796890029e7dadb72eff5336cd0074e1edc9e Mon Sep 17 00:00:00 2001 From: Masahiko Sawada Date: Wed, 14 Oct 2020 14:23:13 +0900 Subject: [PATCH v7] Log the standby recovery conflict waits. --- doc/src/sgml/config.sgml | 22 +++ src/backend/storage/buffer/bufmgr.c | 13 ++ src/backend/storage/ipc/standby.c | 150 +++++++++++++++--- src/backend/storage/lmgr/proc.c | 26 +++ src/backend/utils/misc/guc.c | 10 +- src/backend/utils/misc/postgresql.conf.sample | 2 + src/include/storage/procsignal.h | 1 + src/include/storage/standby.h | 2 + 8 files changed, 205 insertions(+), 21 deletions(-) diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml index ee914740cc..a4a43dff83 100644 --- a/doc/src/sgml/config.sgml +++ b/doc/src/sgml/config.sgml @@ -6839,6 +6839,28 @@ log_line_prefix = '%m [%p] %q%u@%d/%a ' + + log_recovery_conflict_waits (boolean) + + log_recovery_conflict_waits configuration parameter + + + + + Controls whether a log message is produced when the startup process + is waiting for recovery conflicts longer than + deadlock_timeout. This is useful in determining if + recovery conflicts prevents the recovery from applying WAL. + + + + This parameter can only be set in the postgresql.conf + file or on the server command line. + The default is off. + + + + log_parameter_max_length (integer) diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c index e549fa1d30..648ced33eb 100644 --- a/src/backend/storage/buffer/bufmgr.c +++ b/src/backend/storage/buffer/bufmgr.c @@ -3808,6 +3808,8 @@ LockBufferForCleanup(Buffer buffer) { BufferDesc *bufHdr; char *new_status = NULL; + TimestampTz waitStart = 0; + bool logged_recovery_conflict = false; Assert(BufferIsPinned(buffer)); Assert(PinCountWaitBuf == NULL); @@ -3829,6 +3831,9 @@ LockBufferForCleanup(Buffer buffer) bufHdr = GetBufferDescriptor(buffer - 1); + if (log_recovery_conflict_waits) + waitStart = GetCurrentTimestamp(); + for (;;) { uint32 buf_state; @@ -3881,6 +3886,14 @@ LockBufferForCleanup(Buffer buffer) new_status[len] = '\0'; /* truncate off " waiting" */ } + if (log_recovery_conflict_waits && !logged_recovery_conflict && + TimestampDifferenceExceeds(waitStart, GetCurrentTimestamp(), + DeadlockTimeout)) + { + LogRecoveryConflict(PROCSIG_RECOVERY_CONFLICT_BUFFERPIN, NULL); + logged_recovery_conflict = true; + } + /* Publish the bufid that Startup process waits on */ SetStartupBufferPinWaitBufId(buffer - 1); /* Set alarm and then wait to be signaled by UnpinBuffer() */ diff --git a/src/backend/storage/ipc/standby.c b/src/backend/storage/ipc/standby.c index 52b2809dac..5820713566 100644 --- a/src/backend/storage/ipc/standby.c +++ b/src/backend/storage/ipc/standby.c @@ -39,6 +39,7 @@ int vacuum_defer_cleanup_age; int max_standby_archive_delay = 30 * 1000; int max_standby_streaming_delay = 30 * 1000; +bool log_recovery_conflict_waits = false; static HTAB *RecoveryLockLists; @@ -49,6 +50,7 @@ static void ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlis static void SendRecoveryConflictWithBufferPin(ProcSignalReason reason); static XLogRecPtr LogCurrentRunningXacts(RunningTransactions CurrRunningXacts); static void LogAccessExclusiveLocks(int nlocks, xl_standby_lock *locks); +static const char *get_recovery_conflict_desc(ProcSignalReason reason); /* * Keep track of all the locks owned by a given transaction. @@ -215,15 +217,60 @@ WaitExceedsMaxStandbyDelay(uint32 wait_event_info) return false; } +/* + * Log the recovery conflict. + * + * This function also reports the details about the conflicting process ids + * if *waitlist is not NULL. + */ +void +LogRecoveryConflict(ProcSignalReason reason, VirtualTransactionId *waitlist) +{ + if (waitlist) + { + VirtualTransactionId *vxids; + StringInfoData buf; + int nprocs = 0; + + initStringInfo(&buf); + + /* construct a string of list of the conflicted virtual transactions */ + vxids = waitlist; + while (VirtualTransactionIdIsValid(*vxids)) + { + PGPROC *proc = BackendIdGetProc(vxids->backendId); + + if (nprocs == 0) + appendStringInfo(&buf, "%d", proc->pid); + else + appendStringInfo(&buf, ", %d", proc->pid); + + nprocs++; + vxids++; + } + + ereport(LOG, + (errmsg_internal("%s", get_recovery_conflict_desc(reason)), + (errdetail_log_plural("Conflicting process: %s.", + "Conflicting processes: %s.", + nprocs, buf.data)))); + pfree(buf.data); + } + else + ereport(LOG, + (errmsg_internal("%s", get_recovery_conflict_desc(reason)))); +} + /* * This is the main executioner for any query backend that conflicts with * recovery processing. Judgement has already been passed on it within * a specific rmgr. Here we just issue the orders to the procs. The procs * then throw the required error as instructed. * - * If report_waiting is true, "waiting" is reported in PS display if necessary. - * If the caller has already reported that, report_waiting should be false. - * Otherwise, "waiting" is reported twice unexpectedly. + * If report_waiting is true, "waiting" is reported in PS display and log + * the waits for the recovery conflict if necessary. If the caller has already + * reported that, report_waiting should be false. Otherwise, both are reported + * twice unexpectedly. */ static void ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist, @@ -232,6 +279,7 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist, { TimestampTz waitStart = 0; char *new_status; + bool logged = false; /* Fast exit, to avoid a kernel call if there's no work to be done. */ if (!VirtualTransactionIdIsValid(*waitlist)) @@ -249,13 +297,25 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist, /* wait until the virtual xid is gone */ while (!VirtualXactLock(*waitlist, false)) { + TimestampTz ts; + + if (report_waiting) + ts = GetCurrentTimestamp(); + + /* Log the recovery conflict */ + if (log_recovery_conflict_waits && !logged && report_waiting && + TimestampDifferenceExceeds(waitStart, ts, DeadlockTimeout)) + { + LogRecoveryConflict(reason, waitlist); + logged = true; + } + /* * Report via ps if we have been waiting for more than 500 msec * (should that be configurable?) */ if (update_process_title && new_status == NULL && report_waiting && - TimestampDifferenceExceeds(waitStart, GetCurrentTimestamp(), - 500)) + TimestampDifferenceExceeds(waitStart, ts, 500)) { const char *old_status; int len; @@ -408,7 +468,35 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag) ltime = GetStandbyLimitTime(); - if (GetCurrentTimestamp() >= ltime) + if (ltime == 0 || GetCurrentTimestamp() < ltime) + { + EnableTimeoutParams timeouts[2]; + int cnt = 0; + + /* + * Wait (or wait again) until ltime + */ + if (ltime != 0) + { + timeouts[cnt].id = STANDBY_LOCK_TIMEOUT; + timeouts[cnt].type = TMPARAM_AT; + timeouts[cnt].fin_time = ltime; + cnt++; + } + + /* Also, set deadlock timeout for logging purpose if necessary */ + if (log_recovery_conflict_waits) + { + timeouts[cnt].id = STANDBY_TIMEOUT; + timeouts[cnt].type = TMPARAM_AFTER; + timeouts[cnt].delay_ms = DeadlockTimeout; + cnt++; + } + + if (cnt > 0) + enable_timeouts(timeouts, cnt); + } + else { /* * We're already behind, so clear a path as quickly as possible. @@ -419,26 +507,15 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag) /* * Prevent ResolveRecoveryConflictWithVirtualXIDs() from reporting - * "waiting" in PS display by disabling its argument report_waiting - * because the caller, WaitOnLock(), has already reported that. + * "waiting" in PS display and logging recovery conflict by disabling + * its argument report_waiting because the callers have already reported + * that. */ ResolveRecoveryConflictWithVirtualXIDs(backends, PROCSIG_RECOVERY_CONFLICT_LOCK, PG_WAIT_LOCK | locktag.locktag_type, false); } - else - { - /* - * Wait (or wait again) until ltime - */ - EnableTimeoutParams timeouts[1]; - - timeouts[0].id = STANDBY_LOCK_TIMEOUT; - timeouts[0].type = TMPARAM_AT; - timeouts[0].fin_time = ltime; - enable_timeouts(timeouts, 1); - } /* Wait to be signaled by the release of the Relation Lock */ ProcWaitForSignal(PG_WAIT_LOCK | locktag.locktag_type); @@ -1116,3 +1193,36 @@ LogStandbyInvalidations(int nmsgs, SharedInvalidationMessage *msgs, nmsgs * sizeof(SharedInvalidationMessage)); XLogInsert(RM_STANDBY_ID, XLOG_INVALIDATIONS); } + +/* Return the description of recovery conflict */ +static const char * +get_recovery_conflict_desc(ProcSignalReason reason) +{ + const char *reasonDesc = _("unknown reason"); + + switch (reason) + { + case PROCSIG_RECOVERY_CONFLICT_BUFFERPIN: + reasonDesc = _("recovery is waiting recovery conflict on buffer pin"); + break; + case PROCSIG_RECOVERY_CONFLICT_LOCK: + reasonDesc = _("recovery is waiting recovery conflict on lock"); + break; + case PROCSIG_RECOVERY_CONFLICT_TABLESPACE: + reasonDesc = _("recovery is waiting recovery conflict on tablespace"); + break; + case PROCSIG_RECOVERY_CONFLICT_SNAPSHOT: + reasonDesc = _("recovery is waiting recovery conflict on snapshot"); + break; + case PROCSIG_RECOVERY_CONFLICT_STARTUP_DEADLOCK: + reasonDesc = _("recovery is waiting recovery conflict on buffer deadlock"); + break; + case PROCSIG_RECOVERY_CONFLICT_DATABASE: + reasonDesc = _("recovery is waiting recovery conflict on database"); + break; + default: + break; + } + + return reasonDesc; +} diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index 88566bd9fa..01fb0e8462 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -1068,7 +1068,9 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable) ProcWaitStatus myWaitStatus; PGPROC *proc; PGPROC *leader = MyProc->lockGroupLeader; + TimestampTz standbyWaitStart; int i; + bool logged_recovery_conflict = false; /* * If group locking is in use, locks held by members of my locking group @@ -1260,6 +1262,8 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable) else enable_timeout_after(DEADLOCK_TIMEOUT, DeadlockTimeout); } + else + standbyWaitStart = GetCurrentTimestamp(); /* * If somebody wakes us between LWLockRelease and WaitLatch, the latch @@ -1281,6 +1285,28 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable) { /* Set a timer and wait for that or for the Lock to be granted */ ResolveRecoveryConflictWithLock(locallock->tag.lock); + + if (log_recovery_conflict_waits && !logged_recovery_conflict && + TimestampDifferenceExceeds(standbyWaitStart, GetCurrentTimestamp(), + DeadlockTimeout)) + { + VirtualTransactionId *vxids; + int cnt; + + vxids = GetLockConflicts(&locallock->tag.lock, + AccessExclusiveLock, &cnt); + + /* + * Log the recovery conflict if there are still virtual transactions + * conflicting on the lock. + */ + if (cnt > 0) + { + LogRecoveryConflict(PROCSIG_RECOVERY_CONFLICT_LOCK, + vxids); + logged_recovery_conflict = true; + } + } } else { diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c index a62d64eaa4..9d575fac10 100644 --- a/src/backend/utils/misc/guc.c +++ b/src/backend/utils/misc/guc.c @@ -1570,7 +1570,15 @@ static struct config_bool ConfigureNamesBool[] = false, NULL, NULL, NULL }, - + { + {"log_recovery_conflict_waits", PGC_SIGHUP, LOGGING_WHAT, + gettext_noop("Logs standby recovery conflict waits."), + NULL + }, + &log_recovery_conflict_waits, + false, + NULL, NULL, NULL + }, { {"log_hostname", PGC_SIGHUP, LOGGING_WHAT, gettext_noop("Logs the host name in the connection logs."), diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample index 9cb571f7cc..5625681e8a 100644 --- a/src/backend/utils/misc/postgresql.conf.sample +++ b/src/backend/utils/misc/postgresql.conf.sample @@ -553,6 +553,8 @@ # %% = '%' # e.g. '<%u%%%d> ' #log_lock_waits = off # log lock waits >= deadlock_timeout +#log_recovery_conflict_waits = off # log standby recovery conflict waits + # >= deadlock_timeout #log_parameter_max_length = -1 # when logging statements, limit logged # bind-parameter values to N bytes; # -1 means print in full, 0 disables diff --git a/src/include/storage/procsignal.h b/src/include/storage/procsignal.h index 5cb39697f3..7cd988263d 100644 --- a/src/include/storage/procsignal.h +++ b/src/include/storage/procsignal.h @@ -71,5 +71,6 @@ extern void WaitForProcSignalBarrier(uint64 generation); extern void ProcessProcSignalBarrier(void); extern void procsignal_sigusr1_handler(SIGNAL_ARGS); +extern const char *get_procsignal_reason_desc(ProcSignalReason reason); #endif /* PROCSIGNAL_H */ diff --git a/src/include/storage/standby.h b/src/include/storage/standby.h index faaf1d3817..642ce5201a 100644 --- a/src/include/storage/standby.h +++ b/src/include/storage/standby.h @@ -23,6 +23,7 @@ extern int vacuum_defer_cleanup_age; extern int max_standby_archive_delay; extern int max_standby_streaming_delay; +extern bool log_recovery_conflict_waits; extern void InitRecoveryTransactionEnvironment(void); extern void ShutdownRecoveryTransactionEnvironment(void); @@ -38,6 +39,7 @@ extern void CheckRecoveryConflictDeadlock(void); extern void StandbyDeadLockHandler(void); extern void StandbyTimeoutHandler(void); extern void StandbyLockTimeoutHandler(void); +extern void LogRecoveryConflict(ProcSignalReason reason, VirtualTransactionId *waitlist); /* * Standby Rmgr (RM_STANDBY_ID) -- 2.27.0