On Sun, Feb 5, 2012 at 10:23 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Simon Riggs <si...@2ndquadrant.com> writes: >> Please post the patch rather than fixing directly. There's some subtle >> stuff there and it would be best to discuss first. > > Here's a proposed patch for the issues around unlocked updates of > shared-memory state. After going through this I believe that there is > little risk of any real problems in the current state of the code; this > is more in the nature of future-proofing against foreseeable changes. > (One such is that we'd discussed fixing the age() function to work > during Hot Standby.) So I suggest applying this to HEAD but not > back-patching.
All looks very good to me. Agreed. > Except for one thing. I realized while looking at the NEXTOID replay > code that it is completely broken: it only advances > ShmemVariableCache->nextOid when that's less than the value in the WAL > record. So that comparison fails if the OID counter wraps around during > replay. I've fixed this in the attached patch by just forcibly > assigning the new value instead of trying to be smart, and I think > probably that aspect of it needs to be back-patched. Ouch! Well spotted. Suggest fixing that as a separate patch; looks like backpatch to 8.0. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
