From: | Andres Freund <andres(at)2ndquadrant(dot)com> |
---|---|
To: | Ants Aasma <ants(at)cybertec(dot)at> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | WAL CPU overhead/optimization (was Master-slave visibility order) |
Date: | 2013-08-29 22:30:04 |
Message-ID: | 20130829223004.GD4283@awork2.anarazel.de |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 2013-08-30 01:10:40 +0300, Ants Aasma wrote:
> On Fri, Aug 30, 2013 at 12:33 AM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> > FWIW, WAL is still the major bottleneck for INSERT heavy workloads. The
> > per CPU overhead actually minimally increased (at least in my tests), it
> > just scales noticeably better than before.
>
> Interesting. Do you have any insight what is behind the CPU overhead?
> Maybe the solution is to make WAL insertion cheap enough to not
> matter. That won't be easy, but neither are the alternatives.
Funnily by far the biggest thing I have seen in benchmarks is the CRC32
computation. I plan to brush up my ~3 year old CRC32 reimplementation
patch sometime, but afair you had a much better one?
I have some doubts about weakening the hash function by also using FNV
or similar here, so I'd first like to try how much of a difference a
better CRC32 implementation can make with the current XLogInsert()
implementation.
Greetings,
Andres Freund
--
Andres Freund http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Andres Freund | 2013-08-29 22:37:25 | Re: Variadic aggregates vs. project policy |
Previous Message | Tom Lane | 2013-08-29 22:29:34 | Re: Variadic aggregates vs. project policy |