Re: open file counts in 8.1.2?

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(at)bluepolka(dot)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