Filtering WAL records in recovery

There's a long standing requirement for filtering WAL records during
recovery, allowing us to select databases, tables etc.

My approach to this has been to submit a patch for rmgr plugins. 

The patch has other good uses too, most especially being able to decode
WAL records by having access to a continuously maintained catalog.

That patch may not have been understood by many and a recent private
conversation indicated it may be vetoed, though not really sure why.

If we are going to reject the patch on rmgr plugins, then I'd like to
get that overwith as quickly as possible so I can add other code to
allow filtering for Hot Standby by some other route for 8.4.

Thanks,

-- Simon Riggs           www.2ndQuadrant.comPostgreSQL Training, Services and Support