Re: Increasing select max(datecol) from bilkaib where datecol<=date'2008-11-01' and (cr='00' or db='00') speed

From: "Andrus" <kobruleht2(at)hot(dot)ee>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Increasing select max(datecol) from bilkaib where datecol<=date'2008-11-01' and (cr='00' or db='00') speed
Date: 2008-11-12 18:06:47
Message-ID: gff602$1ebo$1@news.hub.org
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Matthew,

Thank you.

bilkaib table contains GL transactions for every day.
00 records are initial balance records and they appear only in start of year
or start of month.
They may present or may be not present for some month if initial balance is
not calculated yet.
If 00 records are present, usuallly there are lot of them for single date
for db and cr columns.
This query finds initial balance date befeore given date.
bilkaib table contains several year transactions so it is large.

>Alternatively if you create an index on (cr, bilkaib) and one on (db,
>bilkaib) then you will be able to use other values in the query too.

I'm sorry I do'nt understand this.
What does the (cr, bilkaib) syntax mean?
Should I create two functions indexes and re-write query as Vladimir
suggests or is there better appoach ?

Andrus.

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