pq_recvbuf: unexpected EOF

Hi

We went live a months back with very low volumn (so far) on
subscription based website.  And we are very happy.  App built on 100%
open source toolstack, with PostgreSQL (of course) at it's heart.  I
Can't tell you how pleased I am with Pg (coming from 5 year experience
with Oracle).

I'm writing to discuss some scaling issues.  After bombarding the
system using HTTPD::Bench::ApacheBench (from CPAN), she starts to fail
some where around 30-50 concurrent requests, depending on the query.
See error messages below.

Any advice would be helpful.
Thanks.  David Link, White Plains, NY

Specs:
 h/w: Dual AMD Athalon
 Red Hat 8.0 / Linux 2.4.7
 Apache 1.3.27 (w/ mod_perl)
 PostgreSQL 7.3.1
 perl 5.8

DB Specs:
  Size: 10 GB
  tables: 280 / largest: 550,000 tuples / 25,000 relpages (8K)
  indexes: 650

ERROR:

[4] LOG:  pq_recvbuf: unexpected EOF on client connection
[4] LOG:  server process (pid 28353) was terminated by signal 11
[5] LOG:  terminating any other active server processes
[4-1] WARNING:  Message from PostgreSQL backend:
[4-2] ^IThe Postmaster has informed me that some other backend
[4-3] ^Idied abnormally and possibly corrupted shared memory.
[4-4] ^II have rolled back the current transaction and am
[4-5] ^Igoing to terminate your database system connection and exit.
[4-6] ^IPlease reconnect to the database system and repeat your query.
[4-1] WARNING:  Message from PostgreSQL backend:
[4-6] ^IPlease reconnect to the database system and repeat your query.
[4-2] ^IThe Postmaster has informed me that some other backend
[4-3] ^Idied abnormally and possibly corrupted shared memory.
[4-4] ^II have rolled back the current transaction and am
[4-5] ^Igoing to terminate your database system connection and exit.
[4-6] ^IPlease reconnect to the database system and repeat your query.
[6] LOG:  all server processes terminated; reinitializing shared memory
and semaphores
[7] LOG:  database system was interrupted at 2003-04-24 16:41:41 EDT
[8] LOG:  checkpoint record is at D/6BF3E0F4
[9] LOG:  redo record is at D/6BF3E0F4; undo record is at 0/0; shutdown
FALSE
[10] LOG:  next transaction id: 27240895; next oid: 217108262
[11] LOG:  database system was not properly shut down; automatic
recovery in progress
[12] LOG:  ReadRecord: record with zero length at D/6BF3E134
[13] LOG:  redo is not required
[7] FATAL:  The database system is starting up
[14] LOG:  database system is ready


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