I'm running Postgres 8.4.20 on RHEL 6.4 and it will occasionally crash. The postgres.log file just says that a PID was terminated. The output from dmesg has a message like this one:
postmaster[22905]: segfault at 686 ip 0000000000000686 sp 00007fff83d72e88 error 14 in postgres[400000+463000]
What can I do to try and figure out what is causing the crash and fix it?