On Wed, 2010-04-21 at 15:27 +0300, Heikki Linnakangas wrote: > Given the discussion about the cyclic nature of XIDs, it would be good > to add an assertion that when a new XID is added to the array, it is > > a) larger than the biggest value already in the array > (TransactionIdFollows(new, head)), and > b) not too far from the smallest value in the array to confuse binary > search (TransactionIdFollows(new, tail)).
We discussed this in November. You convinced me it isn't possible for older xids to stay in the standby because anti-wraparound vacuums would conflict and kick them out. The primary can't run with wrapped xids and neither can the standby. I think that is correct. Adding an assertion isn't going to do much because it's unlikely anybody is going to be running for 2^31 transactions with asserts enabled. Worrying about things like this seems strange when real and negative behaviours are right in our faces elsewhere. Performance and scalability are real world concerns. -- Simon Riggs www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
