From f90c4b58989168a1fe5a2dd48181444a18351bfb Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Mon, 1 Mar 2021 23:08:55 +1300 Subject: [PATCH v5 1/2] Replace some sleep/poll loops with WaitLatch(). Although the replaced sleeps are fairly short, a proposed patch to reduce the frequency of reads of the postmaster pipe could cause the loops to take a very long time to react to postmaster exit. Instead, use the standard waiting infrastructure (with no latch), which can exit automatically based on readiness. Reviewed-by: Heikki Linnakangas Reviewed-by: Fujii Masao Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com --- doc/src/sgml/monitoring.sgml | 4 ++++ src/backend/access/transam/xlog.c | 7 +++---- src/backend/postmaster/pgstat.c | 3 +++ src/backend/replication/walreceiverfuncs.c | 6 ++++-- src/include/pgstat.h | 1 + 5 files changed, 15 insertions(+), 6 deletions(-) diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml index 3513e127b7..cf00210cb3 100644 --- a/doc/src/sgml/monitoring.sgml +++ b/doc/src/sgml/monitoring.sgml @@ -1757,6 +1757,10 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser Waiting for confirmation from a remote server during synchronous replication. + + WalrcvExit + Waiting for the walreceiver to exit. + XactGroupUpdate Waiting for the group leader to update transaction status at diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 377afb8732..e63e19eed3 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -6017,7 +6017,7 @@ recoveryStopsAfter(XLogReaderState *record) * the paused state starts at the end of recovery because of * recovery_target_action=pause, and false otherwise. * - * XXX Could also be done with shared latch, avoiding the pg_usleep loop. + * XXX Could also be done with shared latch, avoiding the WL_TIMEOUT loop. * Probably not worth the trouble though. This state shouldn't be one that * anyone cares about server power consumption in. */ @@ -6046,9 +6046,8 @@ recoveryPausesHere(bool endOfRecovery) HandleStartupProcInterrupts(); if (CheckForStandbyTrigger()) return; - pgstat_report_wait_start(WAIT_EVENT_RECOVERY_PAUSE); - pg_usleep(1000000L); /* 1000 ms */ - pgstat_report_wait_end(); + (void) WaitLatch(NULL, WL_TIMEOUT | WL_EXIT_ON_PM_DEATH, 1000, + WAIT_EVENT_RECOVERY_PAUSE); } } diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index f75b52719d..2dbfb81e40 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -4122,6 +4122,9 @@ pgstat_get_wait_ipc(WaitEventIPC w) case WAIT_EVENT_SYNC_REP: event_name = "SyncRep"; break; + case WAIT_EVENT_WALRCV_EXIT: + event_name = "WalrcvExit"; + break; case WAIT_EVENT_XACT_GROUP_UPDATE: event_name = "XactGroupUpdate"; break; diff --git a/src/backend/replication/walreceiverfuncs.c b/src/backend/replication/walreceiverfuncs.c index 63e60478ea..f51dd2fa20 100644 --- a/src/backend/replication/walreceiverfuncs.c +++ b/src/backend/replication/walreceiverfuncs.c @@ -23,8 +23,10 @@ #include #include "access/xlog_internal.h" +#include "pgstat.h" #include "postmaster/startup.h" #include "replication/walreceiver.h" +#include "storage/latch.h" #include "storage/pmsignal.h" #include "storage/shmem.h" #include "utils/timestamp.h" @@ -208,8 +210,8 @@ ShutdownWalRcv(void) * process. */ HandleStartupProcInterrupts(); - - pg_usleep(100000); /* 100ms */ + (void) WaitLatch(NULL, WL_TIMEOUT | WL_EXIT_ON_PM_DEATH, 100, + WAIT_EVENT_WALRCV_EXIT); } } diff --git a/src/include/pgstat.h b/src/include/pgstat.h index 724068cf87..222e38037c 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -998,6 +998,7 @@ typedef enum WAIT_EVENT_REPLICATION_SLOT_DROP, WAIT_EVENT_SAFE_SNAPSHOT, WAIT_EVENT_SYNC_REP, + WAIT_EVENT_WALRCV_EXIT, WAIT_EVENT_XACT_GROUP_UPDATE } WaitEventIPC; -- 2.30.1