Fix obsolete comment in GetSnapshotData

Hi all

There's an outdated reference to GetOldestXmin(true, true) in
GetSnapshotData. It hasn't had that call signature for a long while
now. Update the comment to reflect the current signature.

diff --git a/src/backend/storage/ipc/procarray.c
b/src/backend/storage/ipc/procarray.c
index f32881b..4bf0243 100644
--- a/src/backend/storage/ipc/procarray.c
+++ b/src/backend/storage/ipc/procarray.c
@@ -1556,7 +1556,8 @@ GetMaxSnapshotSubxidCount(void) *          older than this are known not running any more. *
RecentGlobalXmin:the global xmin (oldest TransactionXmin across all *          running transactions, except those
runningLAZY VACUUM).  This is
 
- *          the same computation done by GetOldestXmin(true, true).
+ *          the same computation done by
+ *          GetOldestXmin(NULL, PROCARRAY_FLAGS_DEFAULT|PROCARRAY_FLAGS_VACUUM) *      RecentGlobalDataXmin: the
globalxmin for non-catalog tables *          >= RecentGlobalXmin *
 


-- Craig Ringer                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services