From: Craig Ringer <ringerc@ringerc.id.au>
To: B Sreejith <bsreejithin@gmail.com>
Cc: Robert Klemme <shortcutter@googlemail.com>
Cc: pgsql-performance@postgresql.org, "sreejith. balakrishnan" <sreejith.balakrishnan@tcs.com>
Subject: Re: Any tool/script available which can be used to measure scalability of an application's database.
Date: Sat, 14 Jul 2012 16:48:57 +0800
Message-ID: <50013279.4090407@ringerc.id.au> (raw)
In-Reply-To: <CANVt3iY4ipHJG3+j=c6iO7GDRBT4m-hKAMD=mkf9P8k6q8S_Uw@mail.gmail.com>
References: <OF43A6984C.A368D80E-ON65257A37.00211A41-65257A37.002DEE2E@tcs.com>
<CAM9pMnMcsU0qWb_a2xPHdJ5oobscptE5votqY2T95GnRw7c=pA@mail.gmail.com>
<CANVt3iY4ipHJG3+j=c6iO7GDRBT4m-hKAMD=mkf9P8k6q8S_Uw@mail.gmail.com>
On 07/14/2012 09:26 AM, B Sreejith wrote:
>
> Dear Robert,
>
> We need to scale up both size and load.
> Could you please provide steps I need to follow.
>
For load, first you need to build a representative sample of your
application's querying patterns by logging queries and analysing the
logs. Produce a load generator based on that data, set up a test copy of
your database, and start pushing the query rate up to see what happens.
For simpler loads you can write a transaction script for pgbench based
on your queries.
For size: Copy your data set, then start duplicating it with munged
copies. Repeat, then use the load generator you wrote for the first part
to see how scaling the data up affects your queries. See if anything is
unacceptably slow (the "auto_explain" module is useful here) and examine it.
The truth is that predicting how complex database driven apps will scale
is insanely hard, because access patterns change as data sizes and user
counts grow. You're likely to land up tuning for a scenario that's quite
different to the one that you actually face when you start hitting
scaling limitations. This doesn't mean you should not investigate, it
just means your trials don't prove anything and the optimisations you
make based on what you learn may not gain you much.
--
Craig Ringer
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To: pgsql-performance@postgresql.org
Cc: ringerc@ringerc.id.au, bsreejithin@gmail.com, shortcutter@googlemail.com, sreejith.balakrishnan@tcs.com
Subject: Re: Any tool/script available which can be used to measure scalability of an application's database.
In-Reply-To: <50013279.4090407@ringerc.id.au>
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