From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 29 Jul 2009 15:57:11 +0000 (+0000)
Subject: Fix a thinko introduced into CountActiveBackends by a recent patch:
X-Git-Url: http://waps.l3s.uni-hannover.de/gitweb/%20%22mailto:postgres95%40openlink.co.uk%22?a=commitdiff_plain;h=2ffae8405d8d2578af0625350c46bf4919455452;p=users%2Fsimon%2Fpostgres.git

Fix a thinko introduced into CountActiveBackends by a recent patch:
we should ignore NULL array entries, not non-NULL ones.  This had the
effect of disabling commit_delay, and could have caused a crash in the
rare race condition the patch was intended to fix.

Bug report and diagnosis by Jeff Janes, in bug #4952.
---

diff --git a/src/backend/storage/ipc/procarray.c b/src/backend/storage/ipc/procarray.c
index d2c01a06a5..d3b94e76fa 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -1137,7 +1137,7 @@ CountActiveBackends(void)
 		 * free list and are recycled. Its contents are nonsense in that case,
 		 * but that's acceptable for this function.
 		 */
-		if (proc != NULL)
+		if (proc == NULL)
 			continue;
 
 		if (proc == MyProc)