Re: Preventing index scans for non-recoverable index AMs

Simon Riggs wrote:
>
> On Wed, 2008-12-17 at 18:01 -0500, Jaime Casanova wrote:
> > On Wed, Dec 17, 2008 at 5:54 PM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> >
> > > We don't yet have a mechanism for an
> > > index AM to say "damn, this index is screwed up, don't use it".
> >
> > mark pg_index.indisvalid and/or pg_index.indisready to false in the
> > hot standby node?
>
> We can't edit the database until recovery is over, so that doesn't help
> us while in recovery mode. So not an option.

Maybe we should add a WAL record that's the physical representation for
"mark this index invalid", and have any transaction that modifies a hash
index write that to WAL. It should be simple code to write, because
the underlying replay is based on a regular heap update.

--
Alvaro Herrera http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.