pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Fabien COELHO <coelho@cri.ensmp.fr>
To: Andres Freund <andres@2ndquadrant.com>
Cc: PostgreSQL Developers <pgsql-hackers@postgresql.org>
Subject: Re: PATCH: pgbench - merging transaction logs
Date: Mon, 23 Mar 2015 20:00:04 +0100 (CET)
Message-ID: <alpine.DEB.2.10.1503231924320.29534@sto> (raw)
In-Reply-To: <20150323162927.GC15229@alap3.anarazel.de>
References: <CA+TgmoZAuB+ZfMhS-LSjqsyv=gA7kBjADWf_A34cUeVTrNUmVA@mail.gmail.com>
	<alpine.DEB.2.10.1503171614580.31431@sto>
	<CA+TgmoZ8eFnFeg14bhWYstRdODLHa+f+zDtPjAweOgmPkLcUww@mail.gmail.com>
	<alpine.DEB.2.10.1503201327170.12124@sto>
	<550CCBE5.8060009@2ndquadrant.com>
	<alpine.DEB.2.10.1503210907380.14445@sto>
	<CAJRYxuL7nRA8PR41dk7dVyKqsRD+t=Moo5zGrrinf0Y9Lj+6FA@mail.gmail.com>
	<alpine.DEB.2.10.1503212036400.14445@sto>
	<CAJRYxuJNJgqK_eyYJwNfhzdnQA-cYmMsczSGwLw5BrzHAz2RXw@mail.gmail.com>
	<alpine.DEB.2.10.1503231644130.19117@sto>
	<20150323162927.GC15229@alap3.anarazel.de>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>


> Guys, I don't see this theoretical discussion going anywhere. I think
> it's time to simply implement this and evaluate it on a bigger
> machine.

Sure. I was kind of hoping that someone else would implement it, because 
I'm a reviewer on this one, and I do not have the bigger machine at hand 
either:-) If nothing happens and when I have some time, I'll do it.

> It can't take very long to implement tosimply just write to one
> file instead of the multiple files as now.

Sure.

> The posix guaranteed fprintf locking should already take care of the 
> rest.

I think I would try with snprintf to reduce locking.

Note that I'm first trying to evaluate logging overhead, but I'm quite far 
from Tomas figures at the moment, looks more like 20% overhead (12 threads 
read-only load, runs at about 130000 tps with full logging, 160000 
without, repeated 5 times with the similar results).

In such a case, a mutex would be a bad idea, but I must add that detailed 
logging is a plain bad idea as well!

-- 
Fabien.


-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers



view thread (31+ messages)  latest in thread

Message-ID: <alpine.DEB.2.10.1503231924320.29534@sto>
Permalink:  ../alpine.DEB.2.10.1503231924320.29534@sto/
Also on:    postgresql.org/message-id/alpine.DEB.2.10.1503231924320.29534@sto

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: coelho@cri.ensmp.fr, andres@2ndquadrant.com
  Subject: Re: PATCH: pgbench - merging transaction logs
  In-Reply-To: <alpine.DEB.2.10.1503231924320.29534@sto>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox