Re: [ADMIN] Query performance difference

From: Travis Smith <tsmith(at)optionshouse(dot)com>
To: 'c k' <shreeseva(dot)learning(at)gmail(dot)com>, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: [ADMIN] Query performance difference
Date: 2008-08-21 20:49:48
Message-ID: D337038284820142B2A3196D1BFE2B470F78E404@spswchi6mail1.peak6.net
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My suggestion was based on your question ..

>Why? What will be the difference?
>Is it in their query execution methods, with/without indexes etc?.

An explain plan would tell you what the execution path is. This should be the same independent of the front end you use.

Things such as drivers, network congestion, local applications running on your desktop may make a query appear to run slower.

Since you are getting different execution times I would suggest looking at how the applications work first. Does the application retrieve and render a subset of the data? or does it fetch the entire rowset and renders that?

It may be a good exercise to monitor the activity ..

http://www.postgresql.org/docs/8.3/static/monitoring.html ( yet another link .. :) )

I would try to isolate the system by restricting concurrent sql or batch jobs while you test.

From: c k [mailto:shreeseva(dot)learning(at)gmail(dot)com]
Sent: Thursday, August 21, 2008 3:22 PM
To: Travis Smith; pgsql-general(at)postgresql(dot)org
Subject: Re: [ADMIN] Query performance difference

What do you want to say?
Please give details. I got an explain from PGAdmin,
as follows
"GroupAggregate (cost=28927.37..35594.39 rows=156871 width=24)"
" -> Sort (cost=28927.37..29319.55 rows=156871 width=24)"
" Sort Key: docacctransactions.accgroupid, docs.docid, docs.docdate"
" -> Hash Join (cost=3337.89..12170.02 rows=156871 width=24)"
" Hash Cond: (docacctransactions.docid = docs.docid)"
" -> Seq Scan on docacctransactions (cost=0.00..3665.71 rows=156871 width=20)"
" -> Hash (cost=2545.06..2545.06 rows=48306 width=8)"
" -> Seq Scan on docs (cost=0.00..2545.06 rows=48306 width=8)"

Can you please give why there is a time difference?

CPK
On Fri, Aug 22, 2008 at 1:44 AM, Travis Smith <tsmith(at)optionshouse(dot)com<mailto:tsmith(at)optionshouse(dot)com>> wrote:

It may be worth-wile to generate an explain plan

http://www.postgresql.org/docs/8.3/interactive/sql-explain.html

From: pgsql-admin-owner(at)postgresql(dot)org<mailto:pgsql-admin-owner(at)postgresql(dot)org> [mailto:pgsql-admin-owner(at)postgresql(dot)org<mailto:pgsql-admin-owner(at)postgresql(dot)org>] On Behalf Of c k
Sent: Thursday, August 21, 2008 2:49 PM
To: pgsql-general(at)postgresql(dot)org<mailto:pgsql-general(at)postgresql(dot)org>; pgsql-admin(at)postgresql(dot)org<mailto:pgsql-admin(at)postgresql(dot)org>
Subject: [ADMIN] Query performance difference

Hello,
I have a question regarding query performance from two pgsql applications. PGadmin III 1.8 and Navicat for postgresql 8. Both connected to same server on local machine 8.3 and runs a same query for appox. 1,60,000 rows with one min, one max and addition of the min and max values on two tables joined on an integer column gives different query execution times with noticible difference. PGAdmin gives 9350ms and Navicat gives 2110ms. Why? What will be the difference?
Is it in their query execution methods, with/without indexes etc?.
Thanks

CPK

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