Re: SELECT creates millions of temp files in a single directory

On Sat, Apr 23, 2022 at 1:58 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> "David G. Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> writes:
> > v12 what?
>
> That ...
>
> > It would help if you can provide a self-contained demonstration
> > that others can then verify and debug (or explain).
>
> ... and that. As this message stands, it's undocumented whining.
> Please see
>
> https://wiki.postgresql.org/wiki/Slow_Query_Questions
>
> for the sort of information we need to debug performance issues.
> There's also
>
> https://wiki.postgresql.org/wiki/Guide_to_reporting_problems
>
> although that's not oriented specifically to performance issues.
>
> (I recall that we have fixed some problems in the past that could
> lead to unreasonable numbers of temp files in hash joins. Whether
> there's more to do, or Peter is running a version that lacks those
> fixes, is impossible to tell with the given info.)
>

Thanks.

I'll add that given the nature of the problem that changing temp_file_limit
away from its default of unlimited may be useful.

https://www.postgresql.org/docs/current/runtime-config-resource.html#RUNTIME-CONFIG-RESOURCE-DISK

David J.