Large database problems

All,

We are having a few problems with a large database in postgres 6.5.2
under Linux 2.2.13 (upgraded from RedHat 6.0).

We have a table of around a million books and a number of tables to
store words in the book's titles for free text indexing. The books
file in base, for instance, is 559M.

1)
The first problem came when I tried to pg_dump the database to a file.
The file got to about 4M in a couple of seconds and did not grow any
more but the pg_dump process started growing until it was 300M or so
(256M RAM installed) at which point I got a

dumpClasses(): command failed. Explanation from backend: 'unknown
protocol character '-' read from backend. (The protocol character is
the first character the backend sends in response to a query it
receives).
'.

error. Syslogd then wrote the following repeatedly to /var/log/messages:

Nov 10 18:34:53 booksdb logger: FATAL: pq_endmessage failed: errno=32
Nov 10 18:34:53 booksdb logger: pq_flush: send() failed: Broken pipe

until I killed the postgres process used by pg_dump (it had a status of
SELECT).

I restarted postmaster without the "-B 3900" option it previously had, and
with "-o -S 512" instead of "-o -S 64000" with no more success.

2)
After one such attempt, I found that I could then no longer connect to the
db - I keep getting:

Connection to database 'booksdb' failed.
pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.

whenever I try to use psql or pg_dump. I can connect to other dbs OK.

Does anyone have any idea what might be going on? Is there any way to recover
this database short of rebuilding it?

Any help gratefully received!

Myles

______________________________________________________

Myles Chippendale - mylesc(at)paneris(dot)org
Net Worker
MJ Chippendale Solutions
77 Hurst Street - 01865 791078
Oxford OX4 1HA

http://www.paneris.co.uk/mylesc.html
Proud to be part of the Paneris collective
http://www.paneris.co.uk/
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