Re: pgsql: Track the current XID wrap limit (or more accurately, the oldest

Tom Lane wrote:
> Log Message:
> -----------
> Track the current XID wrap limit (or more accurately, the oldest unfrozen
> XID) in checkpoint records.  This eliminates the need to recompute the value
> from scratch during database startup, which is one of the two remaining
> reasons for the flatfile code to exist.

1. Cluster is close to the stop limit.
2. Autovacuum runs, updates pg_database and advances oldestXid. Phew!
3. Crash.

After recovery, oldestXid is reset to the old value, and you start
getting warnings again. However, everything seems fine in pg_database,
all the databases have been recently vacuumed. Does autovacuum ever run
to fix that? ISTM it won't.

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com