From 1eb0266fed7ccb63a2430e4fbbaef2300f2aa0d0 Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Tue, 1 Mar 2022 11:38:27 +1300 Subject: [PATCH v2 2/3] Fix waiting in RegisterSyncRequest(). If we run out of space in the checkpointer sync request queue (which is hopefully rare on real systems, but common with very small buffer pool), we wait for it to drain. While waiting, we should report that as a wait event so that users know what is going on, and also handle postmaster death, since otherwise the loop might never terminate if the checkpointer has exited. Discussion: https://postgr.es/m/20220226213942.nb7uvb2pamyu26dj%40alap3.anarazel.de --- doc/src/sgml/monitoring.sgml | 5 +++++ src/backend/storage/sync/sync.c | 4 +++- src/backend/utils/activity/wait_event.c | 3 +++ src/include/utils/wait_event.h | 1 + 4 files changed, 12 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 8620aaddc7..71559442f0 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -2254,6 +2254,11 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser Waiting during recovery when WAL data is not available from any source (pg_wal, archive or stream). + + RegisterSyncRequest + Waiting while sending synchronization requests to the + checkpointer, because the request queue is full. + VacuumDelay Waiting in a cost-based vacuum delay point. diff --git a/src/backend/storage/sync/sync.c b/src/backend/storage/sync/sync.c index e161d57761..0c4d9ce687 100644 --- a/src/backend/storage/sync/sync.c +++ b/src/backend/storage/sync/sync.c @@ -31,6 +31,7 @@ #include "storage/bufmgr.h" #include "storage/fd.h" #include "storage/ipc.h" +#include "storage/latch.h" #include "storage/md.h" #include "utils/hsearch.h" #include "utils/inval.h" @@ -606,7 +607,8 @@ RegisterSyncRequest(const FileTag *ftag, SyncRequestType type, if (ret || (!ret && !retryOnError)) break; - pg_usleep(10000L); + WaitLatch(NULL, WL_EXIT_ON_PM_DEATH | WL_TIMEOUT, 10, + WAIT_EVENT_REGISTER_SYNC_REQUEST); } return ret; diff --git a/src/backend/utils/activity/wait_event.c b/src/backend/utils/activity/wait_event.c index 0706e922b5..ff46a0e3c7 100644 --- a/src/backend/utils/activity/wait_event.c +++ b/src/backend/utils/activity/wait_event.c @@ -497,6 +497,9 @@ pgstat_get_wait_timeout(WaitEventTimeout w) case WAIT_EVENT_RECOVERY_RETRIEVE_RETRY_INTERVAL: event_name = "RecoveryRetrieveRetryInterval"; break; + case WAIT_EVENT_REGISTER_SYNC_REQUEST: + event_name = "RegisterSyncRequest"; + break; case WAIT_EVENT_VACUUM_DELAY: event_name = "VacuumDelay"; break; diff --git a/src/include/utils/wait_event.h b/src/include/utils/wait_event.h index d0345c6b49..1c39ce031a 100644 --- a/src/include/utils/wait_event.h +++ b/src/include/utils/wait_event.h @@ -145,6 +145,7 @@ typedef enum WAIT_EVENT_PG_SLEEP, WAIT_EVENT_RECOVERY_APPLY_DELAY, WAIT_EVENT_RECOVERY_RETRIEVE_RETRY_INTERVAL, + WAIT_EVENT_REGISTER_SYNC_REQUEST, WAIT_EVENT_VACUUM_DELAY, WAIT_EVENT_VACUUM_TRUNCATE } WaitEventTimeout; -- 2.30.2