Re: PITR, checkpoint, and local relations

J.R. Nield <jrnield@usol.com>

From: "J. R. Nield" <jrnield@usol.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Bruce Momjian <pgman@candle.pha.pa.us>, Richard Tucker <richt@multera.com>, PostgreSQL Hacker <pgsql-hackers@postgresql.org>
Date: 2002-08-02T13:48:40Z
Lists: pgsql-hackers
Ok. This is what I wanted to hear, but I had assumed someone decided to
put it in for a reason, and I wasn't going to submit a patch to pull-out
the local buffer manager without clearing it first.

The main area where it seems to get heavy use is during index builds,
and for 'CREATE TABLE AS SELECT...'.

So I will remove the local buffer manager as part of the PITR patch,
unless there is further objection.

On Fri, 2002-08-02 at 00:49, Tom Lane wrote:
> "J. R. Nield" <jrnield@usol.com> writes:
> > I am working on a way to do this with a signal, using holdoffs around
> > calls into the storage-manager and VFS layers to prevent re-entrant
> > calls. The local buffer manager is simple enough that it should be
> > possible to flush them from within a signal handler at most times, but
> > the VFS and storage manager are not safe to re-enter from a handler.
> 
> > Does this sound like a good idea?
> 
> No.  What happened to "simple"?
> 
> Before I'd accept anything like that, I'd rip out the local buffer
> manager and just do everything in the shared manager.  I've never
> seen any proof that the local manager buys any noticeable performance
> gain anyway ... how many people really do anything much with a table
> during its first transaction of existence?
> 
> 			regards, tom lane
> 
-- 
J. R. Nield
jrnield@usol.com