diff options
| -rw-r--r-- | src/backend/storage/lmgr/proc.c | 35 |
1 files changed, 22 insertions, 13 deletions
diff --git a/src/backend/storage/lmgr/proc.c b/src/backend/storage/lmgr/proc.c index d1738c65f57..40eac704dc0 100644 --- a/src/backend/storage/lmgr/proc.c +++ b/src/backend/storage/lmgr/proc.c @@ -1311,14 +1311,28 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable) { PGPROC *autovac = GetBlockingAutoVacuumPgproc(); uint8 statusFlags; + uint8 lockmethod_copy; + LOCKTAG locktag_copy; + /* + * Grab info we need, then release lock immediately. Note this + * coding means that there is a tiny chance that the process + * terminates its current transaction and starts a different one + * before we have a change to send the signal; the worst possible + * consequence is that a for-wraparound vacuum is cancelled. But + * that could happen in any case unless we were to do kill() with + * the lock held, which is much more undesirable. + */ LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE); + statusFlags = ProcGlobal->statusFlags[autovac->pgxactoff]; + lockmethod_copy = lock->tag.locktag_lockmethodid; + locktag_copy = lock->tag; + LWLockRelease(ProcArrayLock); /* * Only do it if the worker is not working to protect against Xid * wraparound. */ - statusFlags = ProcGlobal->statusFlags[autovac->pgxactoff]; if ((statusFlags & PROC_IS_AUTOVACUUM) && !(statusFlags & PROC_VACUUM_FOR_WRAPAROUND)) { @@ -1326,25 +1340,25 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable) StringInfoData locktagbuf; StringInfoData logbuf; /* errdetail for server log */ + /* report the case, if configured to do so */ initStringInfo(&locktagbuf); initStringInfo(&logbuf); - DescribeLockTag(&locktagbuf, &lock->tag); + DescribeLockTag(&locktagbuf, &locktag_copy); appendStringInfo(&logbuf, _("Process %d waits for %s on %s."), MyProcPid, - GetLockmodeName(lock->tag.locktag_lockmethodid, - lockmode), + GetLockmodeName(lockmethod_copy, lockmode), locktagbuf.data); - /* release lock as quickly as possible */ - LWLockRelease(ProcArrayLock); - - /* send the autovacuum worker Back to Old Kent Road */ ereport(DEBUG1, (errmsg("sending cancel to blocking autovacuum PID %d", pid), errdetail_log("%s", logbuf.data))); + pfree(logbuf.data); + pfree(locktagbuf.data); + + /* send the autovacuum worker Back to Old Kent Road */ if (kill(pid, SIGINT) < 0) { /* @@ -1362,12 +1376,7 @@ ProcSleep(LOCALLOCK *locallock, LockMethod lockMethodTable) (errmsg("could not send signal to process %d: %m", pid))); } - - pfree(logbuf.data); - pfree(locktagbuf.data); } - else - LWLockRelease(ProcArrayLock); /* prevent signal from being sent again more than once */ allow_autovacuum_cancel = false; |