Re: inconsistent results querying table partitioned by date

On Sat, 18 May 2019 at 09:30, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Since time is growing short before beta1 wrap, I'm going to go ahead
> and push this in hopes of getting buildfarm cycles on it. But feel
> free to review and look for further improvements. There's plenty
> of time to rethink the data-structure details for the v11 backpatch,
> also.

Thanks for working on this. I did have a look and was a bit
disappointed to see the code will end up calling pull_exec_paramids()
3 times for any expression with exec param IDs. I can knock that down
to just 2 by caching the exec Param IDs of the used quals in
GeneratePruningStepsContext. I imagine you didn't do this since its
possible we reject the qual even after has_exec_param is set, but if
we just delay recording the param IDs until after we're certain we're
using the qual then it should be safe to do this. This also gets rid
of the entire get_partkey_exec_paramids() function, so has the
additional saving of not looping through all the steps once more. I
had thought reducing duplicate work like this was one of the driving
factors for this change, although I understand the main one for this
was fixing the bug Amit was working on.

--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services