Re: sidewinder has one failure - Mailing list pgsql-hackers

From Amit Kapila
Subject Re: sidewinder has one failure
Date
Msg-id CAA4eK1++qy3Q4h+gS2cy7941fm01EJkojJ3N7a27xrwg=_QrhQ@mail.gmail.com
Whole thread Raw
In response to Re: sidewinder has one failure  (Mikael Kjellström <mikael.kjellstrom@mksoft.nu>)
Responses Re: sidewinder has one failure  (Amit Kapila <amit.kapila16@gmail.com>)
Re: sidewinder has one failure  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Fri, Jan 3, 2020 at 6:34 PM Mikael Kjellström
<mikael.kjellstrom@mksoft.nu> wrote:
>
>
> On 2020-01-03 13:01, Amit Kapila wrote:
>
> > 2020-01-02 19:51:05.687 CET [24138:3] FATAL:  insufficient file
> > descriptors available to start server process
> > 2020-01-02 19:51:05.687 CET [24138:4] DETAIL:  System allows 19, we
> > need at least 20.
> > 2020-01-02 19:51:05.687 CET [24138:5] LOG:  database system is shut down
> >
> > Here, I think it is clear that the failure happens because we are
> > setting the value of max_files_per_process as 26 which is low for this
> > machine.  It seems to me that the reason it is failing is that before
> > reaching set_max_safe_fds, it has already seven open files.  Now, I
> > see on my CentOS system, the value of already_open files is 3, 6 and 6
> > respectively for versions HEAD, 12 and 10.  We can easily see the
> > number of already opened files by changing the error level from DEBUG2
> > to LOG for elog message in set_max_safe_fds.  It is not very clear to
> > me how many files we can expect to be kept open during startup?  Can
> > the number vary on different setups?
>
> Hm, where does it get the limit from?  Is it something we set?
>
> Why is this machine different from everybody else when it comes to this
> limit?
>

The problem we are seeing on this machine is that I think we have
seven files opened before we reach function set_max_safe_fds during
startup.  Now, it is not clear to me why it is opening extra file(s)
during start-up as compare to other machines.  I think this kind of
problem could occur if one has set shared_preload_libraries and via
that, some file is getting opened which is not closed or there is some
other configuration due to which this extra file is getting opened.

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



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