Re: CREATE DATABASE ... STRATEGY WAL_LOG issues

Andres Freund <andres@anarazel.de>

From: Andres Freund <andres@anarazel.de>
To: Robert Haas <robertmhaas@gmail.com>
Cc: pgsql-hackers@postgresql.org, Dilip Kumar <dilipbalaut@gmail.com>
Date: 2023-03-22T05:11:58Z
Lists: pgsql-hackers

Attachments

Hi,

On 2023-03-21 09:34:14 -0700, Andres Freund wrote:
> On 2023-03-21 11:33:59 -0400, Robert Haas wrote:
> > That feels like it would be slightly more rational behavior,
> > but I'm not smart enough to guess whether anyone would actually be
> > happier (or less happy) after such a change than they are now.
> 
> Yea, I'm not either. The current behaviour does have the feature that it will
> read in some data for each table, but limits trashing of shared buffers for
> huge tables. That's good if your small to medium sized source database isn't
> in s_b, because the next CREATE DATABASE has a change to not need to read the
> data again. But if you have a source database with lots of small relations, it
> can easily lead to swamping s_b.

Patch with the two minimal fixes attached. As we don't know whether it's worth
changing the strategy, the more minimal fixes seem more appropriate.

Greetings,

Andres Freund

Commits

  1. Fix memory leak and inefficiency in CREATE DATABASE ... STRATEGY WAL_LOG