Re: Re: Too many open files (was Re: spinlock problems reported earlier)

Peter Eisentraut <peter_e@gmx.net> writes:
> Tom Lane writes:
>> I'm not sure why this didn't get dealt with, but I think it's a "must
>> fix" kind of problem for 7.1.  The dbadmin has *got* to be able to
>> limit Postgres' appetite for open file descriptors.

> Use ulimit.

Even if ulimit exists and is able to control that parameter on a given
platform (highly unportable assumptions), it's not really a workable
answer.  fd.c has to stop short of using up all of the actual nfile
limit, or else stuff like the dynamic loader is likely to fail.

> I think this is an unreasonable interference with the customary operating
> system interfaces (e.g., ulimit).  The last thing I want to hear is
> "Postgres is slow and it only opens 100 files per process even though I
> <did something> to allow 32 million."

(1) A dbadmin who hasn't read the run-time configuration doc page (that
you did such a nice job with) is going to have lots of performance
issues besides this one.

(2) The last thing *I* want to hear is stories of a default Postgres
installation causing system-wide instability.  But if we don't insert
an open-files limit that's tighter than the "customary operating system
limit", that's exactly the situation we have, at least on several
popular platforms.
        regards, tom lane