Re: pg11+: pg_ls_*dir LIMIT 1: temporary files .. not closed at end-of-transaction

On Sun, Mar 08, 2020 at 02:37:49PM -0400, Tom Lane wrote:
> Justin Pryzby <pryzby(at)telsasoft(dot)com> writes:
> > While working on a patch, I noticed this pre-existing behavior, which seems to
> > be new since v11, maybe due to changes to SRF.
>
> > |postgres=# SELECT pg_ls_dir('.') LIMIT 1;
> > |WARNING: 1 temporary files and directories not closed at end-of-transaction
>
> Hmm, actually it looks to me like pg_ls_dir has been broken forever.
> The reason the warning didn't show up before v11 is that CleanupTempFiles
> didn't bleat about leaked "allocated" directories before that
> (cf 9cb7db3f0).
>
> I guess we ought to change that function to use returns-a-tuplestore
> protocol instead of thinking it can hold a directory open across calls.
> It's not hard to think of use-cases where the existing behavior would
> cause issues worse than a nanny-ish WARNING, especially on platforms
> with tight "ulimit -n" limits.

Thanks for the analysis.

Do you mean it should enumerate all files during the initial SRF call, or use
something other than the SRF_* macros ?

--
Justin