On Tue, Nov 22, 2011 at 3:23 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > Some time ago, I changed GetOldestXmin() to ignore procs in other > databases resulting in a potentially later xmin. > > GetSnapshotData() was not touched when that happened, even though the > comments say "...This is the same computation done by > GetOldestXmin(true, true)." The transam/README file says it stronger > "GetSnapshotData also performs an oldest-xmin calculation (which had > better > match GetOldestXmin's)". Doh. > > As a result, VACUUM ignores procs in other databases, whereas HOT does > not. That means we aren't cleaning up as much as we could do when > running multiple databases. If its OK for VACUUM, then it must be OK > for HOT cleanup also. > > Attached patch ignores procs in other databases during > GetSnapshotData() when IsMVCCSnapshot(), using similar coding to > GetOldestXmin(). > > Any doubters?
I think this is unsafe for shared catalogs. > I suggest this is backpatched a few releases. -1. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
