pgsql-bugs(at)postgreSQL(dot)org writes:
> users=> update users_tbl set added=TRUE where username like 'neta%';
> pqReadData() -- backend closed the channel unexpectedly.
> bash$ tail ~postgres/server.log
> Server process (pid 23747) exited with status 11 at Tue Oct 24 13:52:29 2000
This backend crash should have left a core file in your database
directory (PGDATA/base/users/core). Can you provide a backtrace
from that corefile using gdb?
regards, tom lane