Re: unlogged tables

On Tue, Nov 16, 2010 at 1:09 PM, Andy Colson <andy@squeakycode.net> wrote:
> I was able to apply and compile and run ok, creating unlogged tables seems
> to work as well.
>
> I patched up pgbench to optionally create unlogged tables, and ran it both
> ways.  I get ~80tps normally, and ~1,500tps with unlogged.  (Thats from
> memory, was playing with it last night at home)

What do you get with normal tables but with fsync, full_page_writes,
and synchronous_commits turned off?

What do you get with normal tables but with sychronous_commit (only) off?

Can you detect any performance regression on normal tables with the
patch vs. without the patch?

> I also have a "real world" test I can try (import apache logs and run a few
> stats).

That would be great.

> What other things would be good to test:
> indexes?
> analyze/stats/plans?
> dump/restore?

All of those.  I guess there's a question of what pg_dump should emit
for an unlogged table.  Clearly, we need to dump a CREATE UNLOGGED
TABLE statement (which we do), and right now we also dump the table
contents - which seems reasonable, but arguably someone could say that
we ought not to dump the contents of anything less than a
full-fledged, permanent table.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company