Maybe my custom settings are relevant. Here they are in a gist: https://gist.github.com/skehlet/08aeed3d06f1c35bc780
On Thu, Mar 17, 2016 at 11:47 AM Steve Kehlet <steve.keh...@gmail.com> wrote: > Sorry, seems like such a noob problem, but I'm stumped. This is postgres > 9.4.5. I'll post my custom settings if desired but I don't think they're > needed. > > We recently had an issue where the autovacuumer wasn't starting because > postgres couldn't resolve the hostname 'localhost' (we had bad perms on > /etc/hosts). We're still working on getting that fixed on all affected > boxes. > > In the meantime: today, one particular database unexpectedly stopped > serving with this error: > > 2016-03-17 12:31:52 EDT [5395]: [787-1] ERROR: database is not accepting > commands to avoid wraparound data loss in database with OID 0 > 2016-03-17 12:31:52 EDT [5395]: [788-1] HINT: Stop the postmaster and > vacuum that database in single-user mode. > You might also need to commit or roll back old prepared > transactions. > > What has me confused is I ran the following command to keep an eye on > this, and it seemed fine, the max(age(datfrozenxid)) was only about 330 > million: > > postgres=# select datname,age(datfrozenxid) from pg_database; > datname | age > -----------+----------- > mydb | 330688846 > postgres | 215500760 > template1 | 198965879 > template0 | 146483694 > mydb2 | 175585538 > (5 rows) > > We shutdown postgres, started it in single user mode, and VACUUMed each > database. Then postgres started up fine, and the crisis is averted, for now. > > However my understanding must be wrong: I thought we could just look > around for max(age(datfrozenxid)), make sure it's "low" (<2 billion), and > be sure that this wouldn't happen. What am I misunderstanding? > > And then, I don't know which db has OID 0? > > postgres=# SELECT oid,datname from pg_database; > oid | datname > ------------+----------- > 16422 | mydb > 12921 | postgres > 1 | template1 > 12916 | template0 > 1575433129 | mydb2 > (5 rows) > > Thank you for your help! > >
