Hello we are running postgres 9.2.5 on RHEL6, our production server crashed hard and when it came back up our logs were flooded with:
STATEMENT: SELECT "session_session"."session_key", "session_session"."session_data", "session_session"."expire_date", "session_session"."nonce" FROM "session_session" WHERE ("session_session"."session_key" = 'gk9aap5d7btp6tzquh0kf73gpfmik5w3' AND "session_session"."expire_date" > '2013-11-21 13:27:33.107913' )
ERROR: unexpected chunk number 0 (expected 1) for toast value 117927127 in pg_toast_19122
We restarted the application and whatever session was constantly hitting that row stopped, but Im concerned about remediation. When I attempt to read from that row the error occurs.
select * from session_session where session_key = 'gk9aap5d7btp6tzquh0kf73gpfmik5w3';
ERROR: unexpected chunk number 0 (expected 1) for toast value 117927127 in pg_toast_19122
When I attempt to delete this row I get this error:
delete from session_session where session_key = 'gk9aap5d7btp6tzquh0kf73gpfmik5w3';
ERROR: tuple concurrently updated
We happen to have a maintenance window tonight so I will have some time when the app is down to run some database fixes. I saw other threads suggesting a reindex of the toast table, but this is a 14GB table and I'm not sure how long that will take or if it will even be successful. We also have a full db vacuum/analyze scheduled nightly for 2am so I am expecting to learn if there are other impacted tables, but its troubling if I dont know what the remediation. This particular table could be truncated if necessary if that is an option but Im not sure about other tables.
Any suggestions for how to handle the tuple concurrently updated error? Or if a reindex is likely to help with the unexpected chunk error?
Thanks
Mike
