diff options
Diffstat (limited to 'src/backend/storage/ipc/procarray.c')
| -rw-r--r-- | src/backend/storage/ipc/procarray.c | 55 |
1 files changed, 28 insertions, 27 deletions
diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c index 0286809d1c4..42ed5865d9c 100644 --- a/src/backend/storage/ipc/procarray.c +++ b/src/backend/storage/ipc/procarray.c @@ -23,7 +23,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.45 2008/07/11 02:10:13 alvherre Exp $ + * $PostgreSQL: pgsql/src/backend/storage/ipc/procarray.c,v 1.46 2008/08/04 18:03:46 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -1177,7 +1177,7 @@ CountUserBackends(Oid roleid) } /* - * CheckOtherDBBackends -- check for other backends running in the given DB + * CountOtherDBBackends -- check for other backends running in the given DB * * If there are other backends in the DB, we will wait a maximum of 5 seconds * for them to exit. Autovacuum backends are encouraged to exit early by @@ -1187,6 +1187,8 @@ CountUserBackends(Oid roleid) * check whether the current backend uses the given DB, if it's important. * * Returns TRUE if there are (still) other backends in the DB, FALSE if not. + * Also, *nbackends and *nprepared are set to the number of other backends + * and prepared transactions in the DB, respectively. * * This function is used to interlock DROP DATABASE and related commands * against there being any active backends in the target DB --- dropping the @@ -1198,19 +1200,24 @@ CountUserBackends(Oid roleid) * indefinitely. */ bool -CheckOtherDBBackends(Oid databaseId) +CountOtherDBBackends(Oid databaseId, int *nbackends, int *nprepared) { ProcArrayStruct *arrayP = procArray; +#define MAXAUTOVACPIDS 10 /* max autovacs to SIGTERM per iteration */ + int autovac_pids[MAXAUTOVACPIDS]; int tries; /* 50 tries with 100ms sleep between tries makes 5 sec total wait */ for (tries = 0; tries < 50; tries++) { + int nautovacs = 0; bool found = false; int index; CHECK_FOR_INTERRUPTS(); + *nbackends = *nprepared = 0; + LWLockAcquire(ProcArrayLock, LW_SHARED); for (index = 0; index < arrayP->numProcs; index++) @@ -1224,38 +1231,32 @@ CheckOtherDBBackends(Oid databaseId) found = true; - if (proc->vacuumFlags & PROC_IS_AUTOVACUUM) - { - /* an autovacuum --- send it SIGTERM before sleeping */ - int autopid = proc->pid; - - /* - * It's a bit awkward to release ProcArrayLock within the - * loop, but we'd probably better do so before issuing kill(). - * We have no idea what might block kill() inside the - * kernel... - */ - LWLockRelease(ProcArrayLock); - - (void) kill(autopid, SIGTERM); /* ignore any error */ - - break; - } + if (proc->pid == 0) + (*nprepared)++; else { - LWLockRelease(ProcArrayLock); - break; + (*nbackends)++; + if ((proc->vacuumFlags & PROC_IS_AUTOVACUUM) && + nautovacs < MAXAUTOVACPIDS) + autovac_pids[nautovacs++] = proc->pid; } } - /* if found is set, we released the lock within the loop body */ + LWLockRelease(ProcArrayLock); + if (!found) - { - LWLockRelease(ProcArrayLock); return false; /* no conflicting backends, so done */ - } - /* else sleep and try again */ + /* + * Send SIGTERM to any conflicting autovacuums before sleeping. + * We postpone this step until after the loop because we don't + * want to hold ProcArrayLock while issuing kill(). + * We have no idea what might block kill() inside the kernel... + */ + for (index = 0; index < nautovacs; index++) + (void) kill(autovac_pids[index], SIGTERM); /* ignore any error */ + + /* sleep, then try again */ pg_usleep(100 * 1000L); /* 100ms */ } |