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Introduce a WaitEventSet for the stats collector.

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This avoids avoids some epoll/kqueue system calls for every wait.

Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
This commit is contained in:
Thomas Munro 2020-07-30 17:25:48 +12:00
parent e2d394df5d
commit e7591fd3ca
1 changed files with 14 additions and 10 deletions
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22
src/backend/postmaster/pgstat.c
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@ -4458,6 +4458,8 @@ PgstatCollectorMain(int argc, char *argv[])
int len;
PgStat_Msg msg;
int wr;
WaitEvent event;
WaitEventSet *wes;
/*
* Ignore all signals usually bound to some action in the postmaster,
@ -4485,6 +4487,12 @@ PgstatCollectorMain(int argc, char *argv[])
pgStatRunningInCollector = true;
pgStatDBHash = pgstat_read_statsfiles(InvalidOid, true, true);
/* Prepare to wait for our latch or data in our socket. */
wes = CreateWaitEventSet(CurrentMemoryContext, 3);
AddWaitEventToSet(wes, WL_LATCH_SET, PGINVALID_SOCKET, MyLatch, NULL);
AddWaitEventToSet(wes, WL_POSTMASTER_DEATH, PGINVALID_SOCKET, NULL, NULL);
AddWaitEventToSet(wes, WL_SOCKET_READABLE, pgStatSock, NULL, NULL);
/*
* Loop to process messages until we get SIGQUIT or detect ungraceful
* death of our parent postmaster.
@ -4672,10 +4680,7 @@ PgstatCollectorMain(int argc, char *argv[])
/* Sleep until there's something to do */
#ifndef WIN32
wr = WaitLatchOrSocket(MyLatch,
WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE,
pgStatSock, -1L,
WAIT_EVENT_PGSTAT_MAIN);
wr = WaitEventSetWait(wes, -1L, &event, 1, WAIT_EVENT_PGSTAT_MAIN);
#else
/*
@ -4688,10 +4693,7 @@ PgstatCollectorMain(int argc, char *argv[])
* to not provoke "using stale statistics" complaints from
* backend_read_statsfile.
*/
wr = WaitLatchOrSocket(MyLatch,
WL_LATCH_SET | WL_POSTMASTER_DEATH | WL_SOCKET_READABLE | WL_TIMEOUT,
pgStatSock,
2 * 1000L /* msec */ ,
wr = WaitEventSetWait(wes, 2 * 1000L /* msec */ , &event, 1,
WAIT_EVENT_PGSTAT_MAIN);
#endif
@ -4699,7 +4701,7 @@ PgstatCollectorMain(int argc, char *argv[])
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (wr & WL_POSTMASTER_DEATH)
if (wr == 1 && event.events == WL_POSTMASTER_DEATH)
break;
} /* end of outer loop */
@ -4708,6 +4710,8 @@ PgstatCollectorMain(int argc, char *argv[])
*/
pgstat_write_statsfiles(true, true);
FreeWaitEventSet(wes);
exit(0);
}