Log Message:
-----------
Xmin calculations should consider only top transaction IDs, and
therefore starting with GetCurrentTransactionId is wrong. Fixes
miscomputation of RecentGlobalXmin leading to bizarre behavior
reported by Gavin Sherry.
Modified Files:
--------------
pgsql-server/src/backend/storage/ipc:
sinval.c (r1.67 -> r1.68)
(http://developer.postgresql.org/cvsweb.cgi/pgsql-server/src/backend/storage/ipc/sinval.c.diff?r1=1.67&r2=1.68)