Re: draft RFC: concept for partial, wal-based replication

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Craig Ringer <craig@postnewspapers.com.au>
Cc: pgsql-hackers@postgresql.org
Date: 2009-11-30T15:07:24Z
Lists: pgsql-hackers
Craig Ringer <craig@postnewspapers.com.au> writes:
> Just a side note: in addition to its use for partial replication, this
> might have potential for performance-prioritizing databases or tablespaces.

> Being able to separate WAL logging so that different DBs, tablespaces,
> etc went to different sets of WAL logs would allow a DBA to give some
> databases or tablespaces dedicated WAL logging space on faster storage.

I don't think this can possibly work without introducing data corruption
issues.  What happens when a transaction touches tables in different
tablespaces?  You can't apply the changes out-of-order.

			regards, tom lane