Re: xlogdump fixups and WAL log question.

On Sat, 2006-10-21 at 09:00 -0400, Theo Schlossnagle wrote:
> On Oct 21, 2006, at 6:08 AM, Martijn van Oosterhout wrote:
> 
> > On Sat, Oct 21, 2006 at 10:37:51AM +0100, Simon Riggs wrote:
> >> Turning off WAL is a difficult topic. Without it you have no crash
> >> recovery, which IMHO everybody says they don't care about until they
> >> crash, then they realise. It's hard to be selective about writing WAL
> >> for specific operations also.
> >
> > It's been discussed before. One idea is to declare tables without
> > logging. The idea being that during recovery those tables and related
> > indexes are simply truncated. No foreign keys allowed. Obviously they
> > will not be saved via PITR either.
> >
> > Put another way, the table structure is saved in WAL, but the data
> > isn't.
> 
> This is exactly what I'd like.  Simon suggested turning off WAL  
> during the loads as a possible hack solution.  The reason this won't  
> work is that we snap all the time, lots of tables.  We have between  
> 2000 and 4000 snapshot operations per day (throughout).  At the same  
> time we have reporting queries running (that create and/or populate  
> other tables) that last from 5 minutes to 18 hours.  It is important  
> that we run everything but the snapshots with WAL on (as we must have  
> PITR -- sans snapshots)

These tables are loaded once then read-only, yes?

--  Simon Riggs              EnterpriseDB   http://www.enterprisedb.com