From 9508754ed7e3b5688c97a26bbe15af7e11d7f06a Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas Date: Thu, 4 Apr 2013 16:31:44 +0300 Subject: [PATCH] Calculate # of semaphores correctly with --disable-spinlocks. The old formula didn't take into account that each WAL sender process needs a spinlock. We had also already exceeded the fixed number of spinlocks reserved for misc purposes (10). Bump that to 30. Backpatch to 9.0, where WAL senders were introduced. If I counted correctly, 9.0 had exactly 10 predefined spinlocks, and 9.1 exceeded that, but bump the limit in 9.0 too because 10 is uncomfortably close to the edge. --- src/backend/storage/lmgr/spin.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/src/backend/storage/lmgr/spin.c b/src/backend/storage/lmgr/spin.c index d262efa300f..56442ed073e 100644 --- a/src/backend/storage/lmgr/spin.c +++ b/src/backend/storage/lmgr/spin.c @@ -23,6 +23,7 @@ #include "postgres.h" #include "miscadmin.h" +#include "replication/walsender.h" #include "storage/lwlock.h" #include "storage/spin.h" @@ -50,14 +51,21 @@ SpinlockSemas(void) int SpinlockSemas(void) { + int nsemas; + /* * It would be cleaner to distribute this logic into the affected modules, * similar to the way shmem space estimation is handled. * - * For now, though, we just need a few spinlocks (10 should be plenty) - * plus one for each LWLock and one for each buffer header. + * For now, though, there are few enough users of spinlocks that we just + * keep the knowledge here. */ - return NumLWLocks() + NBuffers + 10; + nsemas = NumLWLocks(); /* one for each lwlock */ + nsemas += NBuffers; /* one for each buffer header */ + nsemas += max_wal_senders; /* one for each wal sender process */ + nsemas += 30; /* plus a bunch for other small-scale use */ + + return nsemas; } /*