On 2014-04-22 18:01:40 -0300, Alvaro Herrera wrote: > Thanks for the analysis and patches. I've been playing with this on my > own a bit, and one thing that I just noticed is that at least for > heap_update I cannot reproduce a problem when the xmax is originally a > multixact, so AFAICT the number of places that need patched aren't as > many.
I am quite uncomfortable with that assumption. I don't immediately see a problem for some of the cases, but leaving them in a weaker state than 9.2 makes me uncomfortable. > For now I offer a cleaned up version of your patch to add the assertion > that multis don't contain multiple updates. I considered the idea of > making this #ifdef USE_ASSERT_CHECKING, because it has to walk the > complete array of members; and then have full elogs in MultiXactIdExpand > and MultiXactIdCreate, which are lighter because they can check more > easily. But on second thoughts I refrained from doing that, because > surely the arrays are not as large anyway, are they. Yea, I think it's fine to do it where it's in the proposed patch. > I think I should push this patch first, so that Andrew and Josh can try > their respective test cases which should start throwing errors, then > push the actual fixes. Does that sound okay? +1 Greetings, Andres Freund -- Andres Freund 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
