Re: COPY FROM WHEN condition

On Tue, 29 Jan 2019 at 22:51, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> wrote:
>
> On 1/29/19 8:18 AM, David Rowley wrote:
> > So looks like your change slows this code down 4% for this test case.
> > That's about twice as bad as the 2.2% regression that I had to solve
> > for the multi-insert partition patch (of which you've removed much of
> > the code from)
> >
> > I'd really like to see the alternating batch context code being put
> > back in to fix this. Of course, if you have a better idea, then we can
> > look into that, but just removing code that was carefully written and
> > benchmarked without any new benchmarks to prove that it's okay to do
> > so seems wrong to me.
> >
>
> Yeah, that's not very nice. Do you suggest to revert 36a1281f86c0f, or
> shall we try to massage it a bit first? ISTM we could simply create two
> batch memory contexts and alternate those, just like with the expression
> contexts before.

I don't think a revert should be done. I didn't check in detail, but
it seems what you did fixed the memory leak issue for when many tuples
are filtered out. I'd like to have more detail on what Andres is
proposing, but otherwise, I'd imagine we can just have two batch
contexts and alternate between them, as before, but also keep the
per-tuple context too.

--
David Rowley http://www.2ndQuadrant.com/
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