Re: Data corruption issues using streaming replication on 9.0.14/9.2.5/9.3.1

Andres,

> Everytime the server in HS mode allows connections ("consistent recovery state
> reached at ..." and "database system is ready to accept read only
> connections" in the log), the bug can be triggered. If there weren't too
> many transactions at that point, the problem won't occur until the
> standby is restarted.

Oh, so this doesn't just happen when the base backup is first taken;
*any* time the standby is restarted, it can happen. (!!!)

>> If someone is doing PITR based on a snapshot taken with pg_basebackup,
>> that will only trip this corruption bug if the user has hot_standby=on
>> in their config *while restoring*?  Or is it critical if they have
>> hot_standby=on while backing up?
> 
> hot_standby=on only has an effect while starting up with a recovery.conf
> present. So, if you have an old base backup around and all WAL files,
> you can start from that.
> 
> Does that answer your questsions?

Yeah, thanks.

If you have any ideas for how we'd write code to scan for this kind of
corruption, please post them.


-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com