From cfdf4dc4fc9635ac8bf6eaaa5dbbcd364ab29f0c Mon Sep 17 00:00:00 2001 From: Thomas Munro Date: Fri, 23 Nov 2018 20:16:41 +1300 Subject: Add WL_EXIT_ON_PM_DEATH pseudo-event. Users of the WaitEventSet and WaitLatch() APIs can now choose between asking for WL_POSTMASTER_DEATH and then handling it explicitly, or asking for WL_EXIT_ON_PM_DEATH to trigger immediate exit on postmaster death. This reduces code duplication, since almost all callers want the latter. Repair all code that was previously ignoring postmaster death completely, or requesting the event but ignoring it, or requesting the event but then doing an unconditional PostmasterIsAlive() call every time through its event loop (which is an expensive syscall on platforms for which we don't have USE_POSTMASTER_DEATH_SIGNAL support). Assert that callers of WaitLatchXXX() under the postmaster remember to ask for either WL_POSTMASTER_DEATH or WL_EXIT_ON_PM_DEATH, to prevent future bugs. The only process that doesn't handle postmaster death is syslogger. It waits until all backends holding the write end of the syslog pipe (including the postmaster) have closed it by exiting, to be sure to capture any parting messages. By using the WaitEventSet API directly it avoids the new assertion, and as a by-product it may be slightly more efficient on platforms that have epoll(). Author: Thomas Munro Reviewed-by: Kyotaro Horiguchi, Heikki Linnakangas, Tom Lane Discussion: https://postgr.es/m/CAEepm%3D1TCviRykkUb69ppWLr_V697rzd1j3eZsRMmbXvETfqbQ%40mail.gmail.com, https://postgr.es/m/CAEepm=2LqHzizbe7muD7-2yHUbTOoF7Q+qkSD5Q41kuhttRTwA@mail.gmail.com --- src/backend/replication/logical/tablesync.c | 30 ++++++++--------------------- 1 file changed, 8 insertions(+), 22 deletions(-) (limited to 'src/backend/replication/logical/tablesync.c') diff --git a/src/backend/replication/logical/tablesync.c b/src/backend/replication/logical/tablesync.c index 9e682331d2f..38ae1b9ab85 100644 --- a/src/backend/replication/logical/tablesync.c +++ b/src/backend/replication/logical/tablesync.c @@ -159,7 +159,6 @@ finish_sync_worker(void) static bool wait_for_relation_state_change(Oid relid, char expected_state) { - int rc; char state; for (;;) @@ -192,13 +191,9 @@ wait_for_relation_state_change(Oid relid, char expected_state) if (!worker) return false; - rc = WaitLatch(MyLatch, - WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH, - 1000L, WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE); - - /* emergency bailout if postmaster has died */ - if (rc & WL_POSTMASTER_DEATH) - proc_exit(1); + (void) WaitLatch(MyLatch, + WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH, + 1000L, WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE); ResetLatch(MyLatch); } @@ -250,13 +245,9 @@ wait_for_worker_state_change(char expected_state) * but use a timeout in case it dies without sending one. */ rc = WaitLatch(MyLatch, - WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH, + WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH, 1000L, WAIT_EVENT_LOGICAL_SYNC_STATE_CHANGE); - /* emergency bailout if postmaster has died */ - if (rc & WL_POSTMASTER_DEATH) - proc_exit(1); - if (rc & WL_LATCH_SET) ResetLatch(MyLatch); } @@ -593,7 +584,6 @@ copy_read_data(void *outbuf, int minread, int maxread) while (maxread > 0 && bytesread < minread) { pgsocket fd = PGINVALID_SOCKET; - int rc; int len; char *buf = NULL; @@ -632,14 +622,10 @@ copy_read_data(void *outbuf, int minread, int maxread) /* * Wait for more data or latch. */ - rc = WaitLatchOrSocket(MyLatch, - WL_SOCKET_READABLE | WL_LATCH_SET | - WL_TIMEOUT | WL_POSTMASTER_DEATH, - fd, 1000L, WAIT_EVENT_LOGICAL_SYNC_DATA); - - /* Emergency bailout if postmaster has died */ - if (rc & WL_POSTMASTER_DEATH) - proc_exit(1); + (void) WaitLatchOrSocket(MyLatch, + WL_SOCKET_READABLE | WL_LATCH_SET | + WL_TIMEOUT | WL_EXIT_ON_PM_DEATH, + fd, 1000L, WAIT_EVENT_LOGICAL_SYNC_DATA); ResetLatch(MyLatch); } -- cgit v1.2.3