On Fri, 2008-03-28 at 10:35 -0300, Alvaro Herrera wrote: > The problem is that we always consider every transaction's PGPROC->xid > in calculating MyProc->xmin. So if you have a long running > transaction, it doesn't matter how far beyond the snapshots are -- the > value returned by GetOldestXmin will always be at most the old > transaction's Xid. Even if that transaction cannot see the old rows > because all of its snapshots are way in the future.
It may not have a TransactionId yet. So we should have the capability to prevent long running read-only transactions from causing a build up of dead row versions. But long running write transactions would still be a problem. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com PostgreSQL UK 2008 Conference: http://www.postgresql.org.uk -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
