diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 15b94c96c0..7c0a673a8d 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -6952,6 +6952,28 @@ log_line_prefix = '%m [%p] %q%u@%d/%a '
</listitem>
</varlistentry>
+ <varlistentry id="guc-log-recovery-conflict-waits" xreflabel="log_recovery_conflict_waits">
+ <term><varname>log_recovery_conflict_waits</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>log_recovery_conflict_waits</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Controls whether a log message is produced when the startup process
+ is waiting longer than <varname>deadlock_timeout</varname>
+ for recovery conflicts. This is useful in determining if recovery
+ conflicts prevent the recovery from applying WAL.
+ </para>
+
+ <para>
+ The default is <literal>off</literal>. This parameter can only be set
+ in the <filename>postgresql.conf</filename> file or on the server
+ command line.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-log-parameter-max-length" xreflabel="log_parameter_max_length">
<term><varname>log_parameter_max_length</varname> (<type>integer</type>)
<indexterm>
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 04f75020e4..efc382cb8d 100644
--- a/doc/src/sgml/high-availability.sgml
+++ b/doc/src/sgml/high-availability.sgml
@@ -2071,6 +2071,12 @@ if (!triggered)
server. The <structname>pg_stat_database</structname> system view also contains
summary information.
</para>
+
+ <para>
+ Users can control whether a log message is produced when WAL replay is waiting
+ longer than <varname>deadlock_timeout</varname> for conflicts. This
+ is controlled by the <xref linkend="guc-log-recovery-conflict-waits"/> parameter.
+ </para>
</sect2>
<sect2 id="hot-standby-admin">
diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 8f2c482bc8..71b5852224 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -3809,6 +3809,8 @@ LockBufferForCleanup(Buffer buffer)
{
BufferDesc *bufHdr;
char *new_status = NULL;
+ TimestampTz waitStart = 0;
+ bool logged_recovery_conflict = false;
Assert(BufferIsPinned(buffer));
Assert(PinCountWaitBuf == NULL);
@@ -3882,6 +3884,34 @@ LockBufferForCleanup(Buffer buffer)
new_status[len] = '\0'; /* truncate off " waiting" */
}
+ /*
+ * Emit the log message if the startup process is waiting longer
+ * than deadlock_timeout for recovery conflict on buffer pin.
+ *
+ * Skip this if first time through because the startup process has
+ * not started waiting yet in this case. So, the wait start
+ * timestamp is set after this logic.
+ */
+ if (waitStart != 0 && !logged_recovery_conflict)
+ {
+ TimestampTz now = GetCurrentTimestamp();
+
+ if (TimestampDifferenceExceeds(waitStart, now,
+ DeadlockTimeout))
+ {
+ LogRecoveryConflict(PROCSIG_RECOVERY_CONFLICT_BUFFERPIN,
+ waitStart, now, NULL);
+ logged_recovery_conflict = true;
+ }
+ }
+
+ /*
+ * Set the wait start timestamp if logging is enabled and first
+ * time through.
+ */
+ if (log_recovery_conflict_waits && waitStart == 0)
+ waitStart = GetCurrentTimestamp();
+
/* 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 77e81bdbc0..d4b0f65ba2 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;
@@ -53,6 +54,7 @@ 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.
@@ -218,15 +220,83 @@ WaitExceedsMaxStandbyDelay(uint32 wait_event_info)
return false;
}
+/*
+ * Log the recovery conflict.
+ *
+ * wait_start is the timestamp when the caller started to wait.
+ * now is the timestamp when this function has been called.
+ * wait_list is the list of virtual transaction ids assigned to
+ * conflicting processes.
+ */
+void
+LogRecoveryConflict(ProcSignalReason reason, TimestampTz wait_start,
+ TimestampTz now, VirtualTransactionId *wait_list)
+{
+ long secs;
+ int usecs;
+ long msecs;
+ StringInfoData buf;
+ int nprocs = 0;
+
+ TimestampDifference(wait_start, now, &secs, &usecs);
+ msecs = secs * 1000 + usecs / 1000;
+ usecs = usecs % 1000;
+
+ if (wait_list)
+ {
+ VirtualTransactionId *vxids;
+
+ /* Construct a string of list of the conflicting processes */
+ vxids = wait_list;
+ while (VirtualTransactionIdIsValid(*vxids))
+ {
+ PGPROC *proc = BackendIdGetProc(vxids->backendId);
+
+ /* proc can be NULL if the target backend is not active */
+ if (proc)
+ {
+ if (nprocs == 0)
+ {
+ initStringInfo(&buf);
+ appendStringInfo(&buf, "%d", proc->pid);
+ }
+ else
+ appendStringInfo(&buf, ", %d", proc->pid);
+
+ nprocs++;
+ }
+
+ vxids++;
+ }
+ }
+
+ /*
+ * If wait_list is specified, report the list of PIDs of active
+ * conflicting backends in a detail message. Note that if all the backends
+ * in the list are not active, no detail message is logged.
+ */
+ ereport(LOG,
+ errmsg("recovery still waiting after %ld.%03d ms: %s",
+ msecs, usecs, _(get_recovery_conflict_desc(reason))),
+ nprocs > 0 ? errdetail_log_plural("Conflicting process: %s.",
+ "Conflicting processes: %s.",
+ nprocs, buf.data) : 0);
+
+ if (nprocs > 0)
+ pfree(buf.data);
+}
+
/*
* 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 the
+ * wait for recovery conflict is reported in the log, if necessary. If
+ * the caller is responsible for reporting them, report_waiting should be
+ * false. Otherwise, both the caller and this function report the same
+ * thing unexpectedly.
*/
static void
ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
@@ -234,15 +304,16 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
bool report_waiting)
{
TimestampTz waitStart = 0;
- char *new_status;
+ char *new_status = NULL;
+ bool logged_recovery_conflict = false;
/* Fast exit, to avoid a kernel call if there's no work to be done. */
if (!VirtualTransactionIdIsValid(*waitlist))
return;
- if (report_waiting)
+ /* Set the wait start timestamp for reporting */
+ if (report_waiting && (log_recovery_conflict_waits || update_process_title))
waitStart = GetCurrentTimestamp();
- new_status = NULL; /* we haven't changed the ps display */
while (VirtualTransactionIdIsValid(*waitlist))
{
@@ -252,25 +323,6 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
/* wait until the virtual xid is gone */
while (!VirtualXactLock(*waitlist, false))
{
- /*
- * 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))
- {
- const char *old_status;
- int len;
-
- old_status = get_ps_display(&len);
- new_status = (char *) palloc(len + 8 + 1);
- memcpy(new_status, old_status, len);
- strcpy(new_status + len, " waiting");
- set_ps_display(new_status);
- new_status[len] = '\0'; /* truncate off " waiting" */
- }
-
/* Is it time to kill it? */
if (WaitExceedsMaxStandbyDelay(wait_event_info))
{
@@ -289,6 +341,50 @@ ResolveRecoveryConflictWithVirtualXIDs(VirtualTransactionId *waitlist,
if (pid != 0)
pg_usleep(5000L);
}
+
+ if (waitStart != 0 && (!logged_recovery_conflict || new_status == NULL))
+ {
+ TimestampTz now = 0;
+ bool maybe_log_conflict;
+ bool maybe_update_title;
+
+ maybe_log_conflict = (log_recovery_conflict_waits && !logged_recovery_conflict);
+ maybe_update_title = (update_process_title && new_status == NULL);
+
+ /* Get the current timestamp if not report yet */
+ if (maybe_log_conflict || maybe_update_title)
+ now = GetCurrentTimestamp();
+
+ /*
+ * Report via ps if we have been waiting for more than 500
+ * msec (should that be configurable?)
+ */
+ if (maybe_update_title &&
+ TimestampDifferenceExceeds(waitStart, now, 500))
+ {
+ const char *old_status;
+ int len;
+
+ old_status = get_ps_display(&len);
+ new_status = (char *) palloc(len + 8 + 1);
+ memcpy(new_status, old_status, len);
+ strcpy(new_status + len, " waiting");
+ set_ps_display(new_status);
+ new_status[len] = '\0'; /* truncate off " waiting" */
+ }
+
+ /*
+ * Emit the log message if the startup process is waiting
+ * longer than deadlock_timeout for recovery conflict on
+ * buffer pin.
+ */
+ if (maybe_log_conflict &&
+ TimestampDifferenceExceeds(waitStart, now, DeadlockTimeout))
+ {
+ LogRecoveryConflict(reason, waitStart, now, waitlist);
+ logged_recovery_conflict = true;
+ }
+ }
}
/* The virtual transaction is gone now, wait for the next one */
@@ -405,9 +501,18 @@ ResolveRecoveryConflictWithDatabase(Oid dbid)
* hot-standby backend processes. If deadlock_timeout is reached in
* this function, all the backends holding the conflicting locks are
* requested to check themselves for deadlocks.
+ *
+ * logging_conflict should be true if the recovery conflict has not been
+ * logged yet even though logging is enabled. After deadlock_timeout is
+ * reached and the request for deadlock check is sent, we wait again to
+ * be signaled by the release of the lock if logging_conflict is false.
+ * Otherwise we return without waiting again so that the caller can report
+ * the recovery conflict. In this case, then, this function is called again
+ * with logging_conflict=false (because the recovery conflict has already
+ * been logged) and we will wait again for the lock to be released.
*/
void
-ResolveRecoveryConflictWithLock(LOCKTAG locktag)
+ResolveRecoveryConflictWithLock(LOCKTAG locktag, bool logging_conflict)
{
TimestampTz ltime;
@@ -494,6 +599,15 @@ ResolveRecoveryConflictWithLock(LOCKTAG locktag)
backends++;
}
+ /*
+ * Exit if the recovery conflict has not been logged yet even though
+ * logging is enabled, so that the caller can log that. Then
+ * RecoveryConflictWithLock() is called again and we will wait again
+ * for the lock to be released.
+ */
+ if (logging_conflict)
+ goto cleanup;
+
/*
* Wait again here to be signaled by the release of the Relation Lock,
* to prevent the subsequent RecoveryConflictWithLock() from causing
@@ -1209,3 +1323,36 @@ 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 = gettext_noop("unknown reason");
+
+ switch (reason)
+ {
+ case PROCSIG_RECOVERY_CONFLICT_BUFFERPIN:
+ reasonDesc = gettext_noop("recovery conflict on buffer pin");
+ break;
+ case PROCSIG_RECOVERY_CONFLICT_LOCK:
+ reasonDesc = gettext_noop("recovery conflict on lock");
+ break;
+ case PROCSIG_RECOVERY_CONFLICT_TABLESPACE:
+ reasonDesc = gettext_noop("recovery conflict on tablespace");
+ break;
+ case PROCSIG_RECOVERY_CONFLICT_SNAPSHOT:
+ reasonDesc = gettext_noop("recovery conflict on snapshot");
+ break;
+ case PROCSIG_RECOVERY_CONFLICT_STARTUP_DEADLOCK:
+ reasonDesc = gettext_noop("recovery conflict on buffer deadlock");
+ break;
+ case PROCSIG_RECOVERY_CONFLICT_DATABASE:
+ reasonDesc = gettext_noop("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 0366a7cc00..db0cfaa360 100644
--- a/src/backend/storage/lmgr/proc.c
+++ b/src/backend/storage/lmgr/proc.c
@@ -1064,8 +1064,10 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
LWLock *partitionLock = LockHashPartitionLock(hashcode);
PROC_QUEUE *waitQueue = &(lock->waitProcs);
LOCKMASK myHeldLocks = MyProc->heldLocks;
+ TimestampTz standbyWaitStart = 0;
bool early_deadlock = false;
bool allow_autovacuum_cancel = true;
+ bool logged_recovery_conflict = false;
ProcWaitStatus myWaitStatus;
PGPROC *proc;
PGPROC *leader = MyProc->lockGroupLeader;
@@ -1261,6 +1263,14 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
else
enable_timeout_after(DEADLOCK_TIMEOUT, DeadlockTimeout);
}
+ else if (log_recovery_conflict_waits)
+ {
+ /*
+ * Set the wait start timestamp if logging is enabled and in hot
+ * standby.
+ */
+ standbyWaitStart = GetCurrentTimestamp();
+ }
/*
* If somebody wakes us between LWLockRelease and WaitLatch, the latch
@@ -1280,8 +1290,42 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable)
{
if (InHotStandby)
{
- /* Set a timer and wait for that or for the Lock to be granted */
- ResolveRecoveryConflictWithLock(locallock->tag.lock);
+ bool maybe_log_conflict =
+ (standbyWaitStart != 0 && !logged_recovery_conflict);
+
+ /* Set a timer and wait for that or for the lock to be granted */
+ ResolveRecoveryConflictWithLock(locallock->tag.lock,
+ maybe_log_conflict);
+
+ /*
+ * Emit the log message if the startup process is waiting longer
+ * than deadlock_timeout for recovery conflict on lock.
+ */
+ if (maybe_log_conflict)
+ {
+ TimestampTz now = GetCurrentTimestamp();
+
+ if (TimestampDifferenceExceeds(standbyWaitStart, now,
+ DeadlockTimeout))
+ {
+ VirtualTransactionId *vxids;
+ int cnt;
+
+ vxids = GetLockConflicts(&locallock->tag.lock,
+ AccessExclusiveLock, &cnt);
+
+ /*
+ * Log the recovery conflict and the list of PIDs of
+ * backends holding the conflicting lock. Note that we do
+ * logging even if there are no such backends right now
+ * because the startup process here has already waited
+ * longer than deadlock_timeout.
+ */
+ LogRecoveryConflict(PROCSIG_RECOVERY_CONFLICT_LOCK,
+ standbyWaitStart, now, cnt > 0 ? vxids : NULL);
+ logged_recovery_conflict = true;
+ }
+ }
}
else
{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index daf9c127cd..17579eeaca 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -1573,7 +1573,15 @@ 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 033aa335a0..8930a94fff 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -552,6 +552,8 @@
# %% = '%'
# 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/standby.h b/src/include/storage/standby.h
index 9b5cc01c97..a0f3e0bdf0 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);
@@ -32,12 +33,14 @@ extern void ResolveRecoveryConflictWithSnapshot(TransactionId latestRemovedXid,
extern void ResolveRecoveryConflictWithTablespace(Oid tsid);
extern void ResolveRecoveryConflictWithDatabase(Oid dbid);
-extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag);
+extern void ResolveRecoveryConflictWithLock(LOCKTAG locktag, bool logging_conflict);
extern void ResolveRecoveryConflictWithBufferPin(void);
extern void CheckRecoveryConflictDeadlock(void);
extern void StandbyDeadLockHandler(void);
extern void StandbyTimeoutHandler(void);
extern void StandbyLockTimeoutHandler(void);
+extern void LogRecoveryConflict(ProcSignalReason reason, TimestampTz wait_start,
+ TimestampTz cur_ts, VirtualTransactionId *wait_list);
/*
* Standby Rmgr (RM_STANDBY_ID)