Date: Wed, 8 Sep 2010 10:46:29 -0700
From: David Kerr <dmk@mr-paradox.net>
To: pgsql-performance@postgresql.org
Subject: pgbench could not send data to client: Broken pipe
Message-ID: <20100908174629.GD40339@mr-paradox.net>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
User-Agent: Mutt/1.4.2.3i

Howdy,

I'm running pgbench with a fairly large # of clients and getting this error in my PG log file.

Here's the command:
./pgbench -c 1100 testdb -l

I get:
LOG:  could not send data to client: Broken pipe

(I had to modify the pgbench.c file to make it go that high, i changed:
MAXCLIENTS = 2048

I thought maybe i was running out of resources so i checked my ulimits:

 ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) unlimited
max locked memory       (kbytes, -l) unlimited
max memory size         (kbytes, -m) unlimited
open files                      (-n) 2048
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) unlimited
real-time priority              (-r) 0
stack size              (kbytes, -s) unlimited
cpu time               (seconds, -t) unlimited
max user processes              (-u) unlimited
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited


This is Pg 8.3.10. Redhat 64bit, the system has 48 cores, 256G of ram.. 


Any idea what would be causing the error?

thanks

Dave