Skip site navigation (1) Skip section navigation (2)

Re: Could synchronous streaming replication really degrade the performance of the primary?

From: Fujii Masao <masao(dot)fujii(at)gmail(dot)com>
To: MauMau <maumau307(at)gmail(dot)com>
Cc: Claudio Freire <klaussfreire(at)gmail(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: Could synchronous streaming replication really degrade the performance of the primary?
Date: 2012-05-10 18:02:57
Message-ID: CAHGQGwESM47xbuc+d-WPUGyFzoSk2sQ3uWN2cVQpXUC_qyQeKA@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Thu, May 10, 2012 at 8:34 PM, MauMau <maumau307(at)gmail(dot)com> wrote:
> Today, they told me that they ran the test on two virtual machines on a
> single physical machine. They also used pgpool-II in both cases. In
> addition, they may have ran the applications and pgpool-II on the same
> virtual machine as the database server.

So they compared the throughput of one server running on a single machine
(non replication case) with that of two servers (i.e., master and
standby) running
on the same single machine (sync rep case)? The amount of CPU/Mem/IO
resource available per server is not the same between those two cases. So
ISTM it's very unfair for sync rep case. In this situation, I'm not
surprised if I
see 50% performance degradation in sync rep case.

> It sounded to me that the resource is so scarce that concurrency was low, or
> your assumption may be correct. I'll hear more about their environment from
> them.
>
> BTW it's pity that I cannot find any case study of performance of the
> flagship feature of PostgreSQL 9.0/9.1, streaming replication...

Though I cannot show the detail for some reasons, as far as I measured
the performance overhead of sync rep by using pgbench, the overhead of
throughput was less than 10%. When measuring sync rep, I used two
set of physical machine and storage for the master and standby, and
used 1Gbps network between them.

Regards,

-- 
Fujii Masao

In response to

Responses

pgsql-performance by date

Next:From: Vidhya BondreDate: 2012-05-11 10:50:25
Subject: Maximum number of sequences that can be created
Previous:From: MauMauDate: 2012-05-10 15:11:01
Subject: Re: Could synchronous streaming replication really degrade the performance of the primary?

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group