Thomas Munro wrote:
> On 25 August 2014 02:57, Alvaro Herrera <alvhe...@2ndquadrant.com> wrote:
> > Thomas Munro wrote:
> >> The difficulty of course will be testing all these racy cases
> >> reproducibly...
> > Does this help?
> > http://www.postgresql.org/message-id/51fb4305.3070...@2ndquadrant.com
> > The useful trick there is forcing a query to get its snapshot and then
> > go to sleep before actually doing anything, by way of an advisory lock.
> Yes it does, thanks Alvaro and Craig. I think the attached spec
> reproduces the problem using that trick, ie shows NOWAIT blocking,
> presumably in EvalPlanQualFetch (though I haven't stepped through it
> with a debugger yet). I'm afraid I'm out of Postgres hacking cycles
> for a few days, but next weekend I should have a new patch that fixes
> this by teaching EvalPlanQualFetch about wait policies, with isolation
> tests for NOWAIT and SKIP LOCKED.
Álvaro Herrera http://www.2ndQuadrant.com/
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