Re: [HACKERS] Should we cacheline align PGXACT? - Mailing list pgsql-hackers

From Alexander Korotkov
Subject Re: [HACKERS] Should we cacheline align PGXACT?
Date
Msg-id CAPpHfduVGAO71wvvhog=juwxCGPXrzxyf2Kj7Uv+utF=p=8XCw@mail.gmail.com
Whole thread Raw
In response to Re: [HACKERS] Should we cacheline align PGXACT?  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Responses Re: [HACKERS] Should we cacheline align PGXACT?  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
List pgsql-hackers
Hi, Tomas!

On Sat, Feb 11, 2017 at 2:28 AM, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:
As discussed at the Developer meeting ~ a week ago, I've ran a number of benchmarks on the commit, on a small/medium-size x86 machines. I currently don't have access to a machine as big as used by Alexander (with 72 physical cores), but it seems useful to verify the patch does not have negative impact on smaller machines.

In particular I've ran these tests:

* r/o pgbench
* r/w pgbench
* 90% reads, 10% writes
* pgbench with skewed distribution
* pgbench with skewed distribution and skipping

Thank you very much for your efforts!
I took a look at these tests.  One thing catch my eyes.  You warmup database using pgbench run.  Did you consider using pg_prewarm instead?

SELECT sum(x.x) FROM (SELECT pg_prewarm(oid) AS x FROM pg_class WHERE relkind IN ('i', 'r') ORDER BY oid) x;

In my experience pg_prewarm both takes less time and leaves less variation afterwards.

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company 

pgsql-hackers by date:

Previous
From: Petr Jelinek
Date:
Subject: Re: [HACKERS] DROP SUBSCRIPTION and ROLLBACK
Next
From: Michael Paquier
Date:
Subject: Re: [HACKERS] Access inside pg_node_tree from query?