Re: sidewinder has one failure

On Sat, Jan 04, 2020 at 06:56:48AM +0530, Amit Kapila wrote:
> On Sat, Jan 4, 2020 at 6:19 AM Tom Lane <[email protected]> wrote:
> > =?UTF-8?Q?Mikael_Kjellstr=c3=b6m?= <[email protected]> writes:
> > > I tried starting it from cron and then I got:
> > >   max_safe_fds = 981, usable_fds = 1000, already_open = 9
> >
> > Oh!  There we have it then.
> >
> 
> Right.
> 
> >  I wonder if that's a cron bug (neglecting
> > to close its own FDs before forking children) or intentional (maybe
> > it uses those FDs to keep tabs on the children?).
> >
> 
> So, where do we go from here?  Shall we try to identify why cron is
> keeping extra FDs or we assume that we can't predict how many
> pre-opened files there will be?

The latter.  If it helps, you could add a regress.c function
leak_fd_until_max_fd_is(integer) so the main part of the test starts from a
known FD consumption state.

> In the latter case, we either want to
> (a) tweak the test to raise the value of max_files_per_process, (b)
> remove the test entirely.

I generally favor keeping the test, but feel free to decide it's too hard.