Re: open file counts in 8.1.2? - Mailing list pgsql-general

From Ed L.
Subject Re: open file counts in 8.1.2?
Date
Msg-id 200603141046.19215.pgsql@bluepolka.net
Whole thread Raw
In response to Re: open file counts in 8.1.2?  ("Ed L." <pgsql@bluepolka.net>)
Responses Re: open file counts in 8.1.2?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general
On Tuesday March 14 2006 10:31 am, Ed L. wrote:
> On Tuesday March 14 2006 10:25 am, Tom Lane wrote:
> > "Ed L." <pgsql@bluepolka.net> writes:
> > > We're trying to make sense of the number of open files on
> > > an HP-UX 11.23 system that's getting several new 8.1.2
> > > clusters, and in particular why the numbers appear to be
> > > significantly larger than our 7.4 clusters on similar
> > > hardware.  Would there be anything particular to 8.1.2
> > > over 7.4 that would lead to a larger number of open files?
> >
> > This is much too handwavy to provide an intelligent comment
> > on. Get a copy of "lsof" and find out exactly which
> > processes have how many files open, then we'll have some
> > idea what's going on...
>
> We have 3 clusters with 24K, 34K, and 47K open files according
> to lsof.  These same clusters have 164, 179, and 210 active
> connections, respectively.  Their schemas, counting the number
> of user and system entries in pg_class as a generously rough
> measure of potential open files, contain roughly 2000 entries
> each.  Those open files seem pretty plausible, they're just
> much higher than what we see on the older systems.

One lsof curiosity is that one cluster seems to have it's
partition directory listing open about 10K times, including
many times by the same backend process:

COMMAND     PID    USER   FD   TYPE             DEVICE   SIZE/OFF   NODE NAME
postgres   4023  db1dba   49u   REG         64,0x10001      16384   7435 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba   62u   REG         64,0x10001       8192   7673 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba   68u   REG         64,0x10001      16384   7601 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba   78u   REG         64,0x10001      16384   7379 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba   79u   REG         64,0x10001      16384   7380 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba  135u   REG         64,0x10001     352256   7305 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba  136u   REG         64,0x10001     262144   7640 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba  137u   REG         64,0x10001     262144   7642 /db1 (/dev/vgdb1/lvol1)
postgres   4023  db1dba  138u   REG         64,0x10001     262144   7643 /db1 (/dev/vgdb1/lvol1)

Ed

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