Performance Woes

Hi,

I have several databases. They are each about 35gb in size and have about
10.5K relations (count from pg_stat_all_tables) in them. Pg_class is about
26k rows and the data directory contains about 70k files. These are busy
machines, they run about 50 xactions per second, ( aproxx insert / update /
delete about 500 rows per second).

We started getting errors about the number of open file descriptors

: 2007-05-09 03:07:50.083 GMT 1146975740: LOG: 53000: out of file
descriptors: Too many open files; release and retry

2007-05-09 03:07:50.083 GMT 1146975740: CONTEXT: SQL statement "insert …..
"

PL/pgSQL function "trigfunc_whatever" line 50 at execute statement

2007-05-09 03:07:50.083 GMT 1146975740: LOCATION: BasicOpenFile, fd.c:471

2007-05-09 03:07:50.091 GMT 0: LOG: 00000: duration: 12.362 ms

2007-05-09 03:07:50.091 GMT 0: LOCATION: exec_simple_query, postgres.c:1090

So we decreased the max_files_per_process to 800. This took care of the
error *BUT* about quadrupled the IO wait that is happening on the machine.
It went from a peek of about 50% to peeks of over 200% (4 processor
machines, 4 gigs ram, raid). The load on the machine remained constant.

I am really to get an understanding of exactly what this setting is and
‘what’ is out of file descriptors and how I can fix that. I need to bring
that IO back down.

Thanks for any help.

Ralph

--
Internal Virus Database is out-of-date.
Checked by AVG Free Edition.
Version: 7.5.432 / Virus Database: 268.15.9/573 - Release Date: 05/12/2006
16:07