Re: need to speed up query - Mailing list pgsql-performance

From Justin
Subject Re: need to speed up query
Date
Msg-id 481FF12D.4080600@emproshunts.com
Whole thread Raw
In response to Re: need to speed up query  ("Gregory Williamson" <Gregory.Williamson@digitalglobe.com>)
List pgsql-performance
Gregory Williamson wrote:

Justin --

You wrote:

> i've had to write queries to get trail balance values out of the GL
> transaction table and i'm not happy with its performance
>
>
> The table has 76K rows growing about 1000 rows per working day so the
> performance is not that great it takes about 20 to 30 seconds to get all
> the records for the table and when we limit it to single accounting
> period it drops down to 2 seconds

So 30 seconds for 76 days (roughly) worth of numbers ? Not terrible but not great.

> Here is the query and explain .  PostgreSql  is 8.3.1 on new server with
> raid 10 Serial SCSI.
<... snipped 'cause I have a lame reader ...>
not according to the bench marks i have done,  which were posted a couple of months ago.


> "  Sort Method:  quicksort  Memory: 292kB"
<...snip...>
> "Total runtime: 24682.580 ms"


I don't have any immediate thoughts but maybe you could post the table schemas and indexes. It looks to my untutored eye as if most of the estimates are fair so I am guessing that you have run analyze recently.

What is your sort memory set to ? If work_mem is too low then you'll go to disk (if you see tmp files under the postgres $PGDATA/base directory you might be seeing the result of this) ...

i need to look into work mem its set at 25 megs which is fine for most work unless we get into the accounting queries which have to be more complicated than they need to be because how some of the tables are laid out which i did not lay out.


HTH

Greg Williamson
Senior DBA
DigitalGlobe

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