Re: [HACKERS] file descriptors leak?

On Tue, 2 Nov 1999, Tom Lane wrote:

> Date: Tue, 02 Nov 1999 10:18:15 -0500
> From: Tom Lane <tgl@sss.pgh.pa.us>
> To: Gene Sokolov <hook@aktrad.ru>
> Cc: pgsql-hackers@postgreSQL.org
> Subject: Re: [HACKERS] file descriptors leak? 
> 
> "Gene Sokolov" <hook@aktrad.ru> writes:
> > We disconnected all clients and the number of descriptors dropped from 800
> > to about 200, which is reasonable. We currently have 3 connections and ~300
> > used descriptors. The "lsof -u postgres" is attached.
> 
> Hmm, I see a postmaster with 8 open files and one backend with 34.
> Doesn't look out of the ordinary to me.

I see 617 open files (using lsof| grep post | wc).
This is a Linux 2.0.37, postgres 6.5.3, 1 postamster and
10 backends. I  already complained about this and would glad
to understand now is it ok or postgres just wast fd ?



> 
> > It seems ok except for a large number of open /dev/null.
> 
> I see /dev/null at the stdin/stdout/stderr positions, which I suppose
> means that you started the postmaster with -S instead of directing its
> output to a logfile.

In my case most files just /dev/sda.....

> 
> It is true that on a system that'll let individual processes have as
> many open file descriptors as they want, Postgres can soak up a lot.
> Over time I'd expect each backend to acquire an FD for practically
> every file in the database directory (including system tables and
> indexes).  So in a large installation you could be looking at thousands
> of open files.  But the situation you're describing doesn't seem like
> it should reach those kinds of numbers.
> 
> The number of open files per backend can be constrained by fd.c, but
> AFAIK there isn't any way to set a manually-specified upper limit; it's
> all automatic.  Perhaps there should be a configuration option to add
> a limit.
> 
>             regards, tom lane
> 
> ************
> 

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