Re: logical decoding : exceeded maxAllocatedDescs for .spill files

On Sat, Jan 11, 2020 at 11:16 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> writes:
> > On Fri, Jan 10, 2020 at 9:31 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >> ... So, we have the below
> >> options:
> >> (a) remove this test entirely from all branches and once we found the
> >> memory leak problem in back-branches, then consider adding it again
> >> without max_files_per_process restriction.
> >> (b) keep this test without max_files_per_process restriction till v11
> >> and once the memory leak issue in v10 is found, we can back-patch to
> >> v10 as well.
>
> > I am planning to go with option (a) and attached are patches to revert
> > the entire test on HEAD and back branches. I am planning to commit
> > these by Tuesday unless someone has a better idea.
>
> Makes sense to me. We've certainly found out something interesting
> from this test, but not what it was expecting to find ;-). I think
> that there could be scope for two sorts of successor tests:
>
> * I still like my idea of directly constraining max_safe_fds through
> some sort of debug option. But to my mind, we want to run the entire
> regression suite with that restriction, not just one small test.
>

Good idea.

> * The seeming bug in v10 suggests that we aren't testing large enough
> logical-decoding cases, or at least aren't noticing leaks in that
> area. I'm not sure what a good design is for testing that. I'm not
> thrilled with just using a larger (and slower) test case, but it's
> not clear to me how else to attack it.
>

It is not clear to me either at this stage, but I think we can decide
that after chasing the issue in v10. My current plan is to revert
this test and make a note of the memory leak problem found (probably
track in Older Bugs section of PostgreSQL 12 Open Items). I think
once we found the issue id v10, we might be in a better position to
decide if the test on the lines of the current test would make sense
or we need something else.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com