Re: BUG #10533: 9.4 beta1 assertion failure in autovacuum process

On 2014-06-05 23:34:36 +0200, Andres Freund wrote:
> Hi,
>
> On 2014-06-05 21:42:23 +0300, Heikki Linnakangas wrote:
> > I think we'll need a variant of GetMultiXactIdMembers() that only returns
> > the update XID, avoiding the palloc(). The straight-forward fix would be to
> > copy-paste contents of GetMultiXactIdMembers() into
> > MultiXactIdGetUpdateXid(), and instead of returning the members in an array,
> > only return the update-xid. But it's a long and complicated function, so
> > copy-pasting is not a good option. I think it needs to be refactored into
> > some kind of a helper function that both MultiXactIdGetUpdateXid() and
> > GetMultiXactIdMembers() could call.
>
> While it certainly would be nice to have such a function I have my doubt
> it's realistic to get it for 9.4 and the backbranches.
>
> I haven't thought particularly much about this, but I don't really see
> why the heap_page_is_all_visible() bit needs to be in a critical
> section? Can't we just do that entire bit after the log_heap_clean()?
> Then the heap_page_is_all_visible() can be done outside a critical
> section.

Before I start working on a patch along those lines, do you see any
problems with making the critical section smaller?

Greetings,

Andres Freund

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Andres Freund http://www.2ndQuadrant.com/
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