On 2014-05-02 18:57:08 -0700, Josh Berkus wrote: > Just got a report of a replication issue with 9.2.8 from a community member: > > Here's the sequence: > > 1) A --> B (sync rep) > > 2) Shut down B > > 3) Shut down A > > 4) Start up B as a master > > 5) Start up A as sync replica of B > > 6) A successfully joins B as a sync replica, even though its transaction > log is 1016 bytes *ahead* of B. > > 7) Transactions written to B all hang > > 8) Xlog on A is now corrupt, although the database itself is OK
This is fundamentally borked practice. > Now, the above sequence happened because of the user misunderstanding > what sync rep really means. However, A should not have been able to > connect with B in replication mode, especially in sync rep mode; that > should have failed. Any thoughts on why it didn't? I'd guess that B, while starting up, has written further WAL records bringing it further ahead of A. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
