Re: PostgreSQL 9.1 "database system was interrupted; last known up at"

"Boylan, Ross" <Ross.Boylan@ucsf.edu> writes:
> I had to power cycle my system because it became unresponsive.  Now PosgtreSQL will not start.  I would like advice
abouthow to proceed; I think pg_resetxlog is my next step.  I have made a copy of the current database files. 
> <log file="postgresql-9.1-main.log">
> 2015-05-25 10:44:21 PDT LOG:  database system was interrupted; last known up at 2015-05-22 09:22:25 PDT
> 2015-05-25 10:44:21 PDT LOG:  incomplete startup packet
> 2015-05-25 10:44:21 PDT FATAL:  could not open file "/etc/ssl/certs/ssl-cert-snakeoil.pem": Permission denied

You did not say, but I'm betting you recently updated to last week's
release, 9.1.16?

If so, this is an unforeseen side-effect of a patch to forcibly fsync
everything in the PG data directory after a crash, see
http://www.postgresql.org/message-id/flat/20150523172627.GA24277@msg.df7cb.de

We're debating how to fix it for real, but in the meantime the easiest
workaround is to change the permissions on that file so it's writable by
Postgres.  (Yeah, I know, ick.  Make a note to undo that after we fix
the fsync'ing logic.)

            regards, tom lane