diff options
| -rw-r--r-- | doc/src/sgml/high-availability.sgml | 12 | ||||
| -rw-r--r-- | src/backend/access/transam/xlogrecovery.c | 6 | ||||
| -rw-r--r-- | src/backend/postmaster/postmaster.c | 12 | ||||
| -rw-r--r-- | src/backend/tcop/backend_startup.c | 18 | ||||
| -rw-r--r-- | src/include/storage/pmsignal.h | 1 | ||||
| -rw-r--r-- | src/include/tcop/backend_startup.h | 2 |
6 files changed, 38 insertions, 13 deletions
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index acf3ac0601d..b47d8b4106e 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -1535,7 +1535,8 @@ synchronous_standby_names = 'ANY 2 (s1, s2, s3)' <para> When the <xref linkend="guc-hot-standby"/> parameter is set to true on a standby server, it will begin accepting connections once the recovery has - brought the system to a consistent state. All such connections are + brought the system to a consistent state and be ready for hot standby. + All such connections are strictly read-only; not even temporary tables may be written. </para> @@ -1974,9 +1975,12 @@ LOG: database system is ready to accept read-only connections Consistency information is recorded once per checkpoint on the primary. It is not possible to enable hot standby when reading WAL written during a period when <varname>wal_level</varname> was not set to - <literal>replica</literal> or <literal>logical</literal> on the primary. Reaching - a consistent state can also be delayed in the presence of both of these - conditions: + <literal>replica</literal> or <literal>logical</literal> on the primary. + Even after reaching a consistent state, the recovery snapshot may not + be ready for hot standby if both of the following conditions are met, + delaying accepting read-only connections. To enable hot standby, + long-lived write transactions with more than 64 subtransactions + need to be closed on the primary. <itemizedlist> <listitem> diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.c index 0aa3ab59085..6ce979f2d8b 100644 --- a/src/backend/access/transam/xlogrecovery.c +++ b/src/backend/access/transam/xlogrecovery.c @@ -291,6 +291,11 @@ static bool backupEndRequired = false; * Consistent state means that the system is internally consistent, all * the WAL has been replayed up to a certain point, and importantly, there * is no trace of later actions on disk. + * + * This flag is used only by the startup process and postmaster. When + * minRecoveryPoint is reached, the startup process sets it to true and + * sends a PMSIGNAL_RECOVERY_CONSISTENT signal to the postmaster, + * which then sets it to true upon receiving the signal. */ bool reachedConsistency = false; @@ -2248,6 +2253,7 @@ CheckRecoveryConsistency(void) CheckTablespaceDirectory(); reachedConsistency = true; + SendPostmasterSignal(PMSIGNAL_RECOVERY_CONSISTENT); ereport(LOG, (errmsg("consistent recovery state reached at %X/%X", LSN_FORMAT_ARGS(lastReplayedEndRecPtr)))); diff --git a/src/backend/postmaster/postmaster.c b/src/backend/postmaster/postmaster.c index c966c2e83af..3fe45de5da0 100644 --- a/src/backend/postmaster/postmaster.c +++ b/src/backend/postmaster/postmaster.c @@ -1825,8 +1825,7 @@ canAcceptConnections(BackendType backend_type) else if (!FatalError && pmState == PM_STARTUP) return CAC_STARTUP; /* normal startup */ else if (!FatalError && pmState == PM_RECOVERY) - return CAC_NOTCONSISTENT; /* not yet at consistent recovery - * state */ + return CAC_NOTHOTSTANDBY; /* not yet ready for hot standby */ else return CAC_RECOVERY; /* else must be crash recovery */ } @@ -3699,6 +3698,7 @@ process_pm_pmsignal(void) /* WAL redo has started. We're out of reinitialization. */ FatalError = false; AbortStartTime = 0; + reachedConsistency = false; /* * Start the archiver if we're responsible for (re-)archiving received @@ -3724,9 +3724,15 @@ process_pm_pmsignal(void) UpdatePMState(PM_RECOVERY); } - if (CheckPostmasterSignal(PMSIGNAL_BEGIN_HOT_STANDBY) && + if (CheckPostmasterSignal(PMSIGNAL_RECOVERY_CONSISTENT) && pmState == PM_RECOVERY && Shutdown == NoShutdown) { + reachedConsistency = true; + } + + if (CheckPostmasterSignal(PMSIGNAL_BEGIN_HOT_STANDBY) && + (pmState == PM_RECOVERY && Shutdown == NoShutdown)) + { ereport(LOG, (errmsg("database system is ready to accept read-only connections"))); diff --git a/src/backend/tcop/backend_startup.c b/src/backend/tcop/backend_startup.c index a07c59ece01..84e1c6f2831 100644 --- a/src/backend/tcop/backend_startup.c +++ b/src/backend/tcop/backend_startup.c @@ -18,6 +18,7 @@ #include <unistd.h> #include "access/xlog.h" +#include "access/xlogrecovery.h" #include "common/ip.h" #include "common/string.h" #include "libpq/libpq.h" @@ -306,17 +307,24 @@ BackendInitialize(ClientSocket *client_sock, CAC_state cac) (errcode(ERRCODE_CANNOT_CONNECT_NOW), errmsg("the database system is starting up"))); break; - case CAC_NOTCONSISTENT: - if (EnableHotStandby) + case CAC_NOTHOTSTANDBY: + if (!EnableHotStandby) + ereport(FATAL, + (errcode(ERRCODE_CANNOT_CONNECT_NOW), + errmsg("the database system is not accepting connections"), + errdetail("Hot standby mode is disabled."))); + else if (reachedConsistency) ereport(FATAL, (errcode(ERRCODE_CANNOT_CONNECT_NOW), errmsg("the database system is not yet accepting connections"), - errdetail("Consistent recovery state has not been yet reached."))); + errdetail("Recovery snapshot is not yet ready for hot standby."), + errhint("To enable hot standby, close write transactions with more than %d subtransactions on the primary server.", + PGPROC_MAX_CACHED_SUBXIDS))); else ereport(FATAL, (errcode(ERRCODE_CANNOT_CONNECT_NOW), - errmsg("the database system is not accepting connections"), - errdetail("Hot standby mode is disabled."))); + errmsg("the database system is not yet accepting connections"), + errdetail("Consistent recovery state has not been yet reached."))); break; case CAC_SHUTDOWN: ereport(FATAL, diff --git a/src/include/storage/pmsignal.h b/src/include/storage/pmsignal.h index d84a383047e..67fa9ac06e1 100644 --- a/src/include/storage/pmsignal.h +++ b/src/include/storage/pmsignal.h @@ -33,6 +33,7 @@ typedef enum { PMSIGNAL_RECOVERY_STARTED, /* recovery has started */ + PMSIGNAL_RECOVERY_CONSISTENT, /* recovery has reached consistent state */ PMSIGNAL_BEGIN_HOT_STANDBY, /* begin Hot Standby */ PMSIGNAL_ROTATE_LOGFILE, /* send SIGUSR1 to syslogger to rotate logfile */ PMSIGNAL_START_AUTOVAC_LAUNCHER, /* start an autovacuum launcher */ diff --git a/src/include/tcop/backend_startup.h b/src/include/tcop/backend_startup.h index 578828c1caf..dcb9d056643 100644 --- a/src/include/tcop/backend_startup.h +++ b/src/include/tcop/backend_startup.h @@ -36,7 +36,7 @@ typedef enum CAC_state CAC_STARTUP, CAC_SHUTDOWN, CAC_RECOVERY, - CAC_NOTCONSISTENT, + CAC_NOTHOTSTANDBY, CAC_TOOMANY, } CAC_state; |