Re: [HACKERS] Hashjoin status report

> The Hermit Hacker <scrappy(at)hub(dot)org> writes:
> >> Opinions? Should I plow ahead, or leave this to fix after 6.5 release?
>
> > Estimate of time involved to fix this? vs likelihood of someone
> > triggering the bug in production?
>
> I could probably get the coding done this weekend, unless something else
> comes up to distract me. It's the question of how much testing it'd
> receive before release that worries me...
>
> As for the likelihood, that's hard to say. It's very easy to trigger
> the bug as a test case. (Arrange for a hashjoin where the inner table
> has a lot of identical rows, or at least many sets of more-than-10-
> rows-with-the-same-value-in-the-field-being-hashed-on.) In real life
> you'd like to think that that's pretty improbable.
>
> What started this go-round was Contzen's report of seeing the
> "hash table out of memory. Use -B parameter to increase buffers"
> message in what was evidently a real-life scenario. So it can happen.
> Do you recall having seen many complaints about that error before?

New optimizer does more hashjoins, so we will see it more often.

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