Nigel Gilbert <n.gilbert@soc.surrey.ac.uk> writes:
> How do I start tracking down the cause?
Look in the postmaster's stderr log to see what gets logged. (If you're
not keeping the log output, now's a good time to start.) Look to see if
a core file gets dropped in the database subdirectory
($PGDATA/base/whatever/); if so, try to extract a stack trace from it
with gdb.
regards, tom lane