Date: Thu, 31 Mar 2016 12:18:05 +0200
From: Andres Freund <andres@anarazel.de>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Speed up Clog Access by increasing CLOG buffers
Message-ID: <20160331101804.GD23562@awork2.anarazel.de>
References: 
 <CAA4eK1+8=X9mSNeVeHg_NqMsOR-XKsjuqrYzQf=iCsdh3U4EOA@mail.gmail.com>
 <20150903114137.GE27649@awork2.anarazel.de>
 <CAA4eK1LMMGNQ439BUm0LcS3p0sb8S9kc-cUGU_ThNqMwA8_Tug@mail.gmail.com>
 <CAA4eK1+-=18HOrdqtLXqOMwZDbC_15WTyHiFruz7BvVArZPaAw@mail.gmail.com>
 <20160330230914.GH13305@awork2.anarazel.de>
 <CAA4eK1L2KO18G5-ajNitztnmn1G_Ex1N4oUHhF0Xx3QrY57Ufw@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: 
 <CAA4eK1L2KO18G5-ajNitztnmn1G_Ex1N4oUHhF0Xx3QrY57Ufw@mail.gmail.com>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

On 2016-03-31 15:07:22 +0530, Amit Kapila wrote:
> On Thu, Mar 31, 2016 at 4:39 AM, Andres Freund <andres@anarazel.de> wrote:
> >
> > On 2016-03-28 22:50:49 +0530, Amit Kapila wrote:
> > > On Fri, Sep 11, 2015 at 8:01 PM, Amit Kapila <amit.kapila16@gmail.com>
> > > wrote:
> > > >
> >
> > Amit, could you run benchmarks on your bigger hardware? Both with
> > USE_CONTENT_LOCK commented out and in?
> >
> 
> Yes.

Cool.


> > I think we should go for 1) and 2) unconditionally.

> Yes, that makes sense.  On 20 min read-write pgbench --unlogged-tables
> benchmark, I see that with HEAD Tps is 36241 and with increase the clog
> buffers patch, Tps is 69340 at 128 client count (very good performance
> boost) which indicates that we should go ahead with 1) and 2) patches.

Especially considering the line count... I do wonder about going crazy
and increasing to 256 immediately. It otherwise seems likely that we'll
have the the same issue in a year.  Could you perhaps run your test
against that as well?


> I think we should change comments on top of this function.

Yes, definitely.


> 0001-Improve-64bit-atomics-support
> 
> +#if 0
> +#ifndef PG_HAVE_ATOMIC_READ_U64
> +#define PG_HAVE_ATOMIC_READ_U64
> +static inline uint64
> 
> What the purpose of above #if 0?  Other than that patch looks good to me.

I think I was investigating something. Other than that obviously there's
no point. Sorry for that.

Greetings,

Andres Freund


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