Re: optimizing Postgres queries

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От
David Teran
Тема
Re: optimizing Postgres queries
Дата
Msg-id
64C8DBBA-3F77-11D8-A528-000A95A6F0DC@cluster9.com
Ответ на
Re: optimizing Postgres queries (Shridhar Daithankar)
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optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Shridhar Daithankar <shridhar_daithankar@myrealbox.com>
Re: optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Shridhar Daithankar <shridhar_daithankar@myrealbox.com>
Re: optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Shridhar Daithankar <shridhar_daithankar@persistent.co.in>
Re: optimizing Postgres queries Tom Lane <tgl@sss.pgh.pa.us>
Re: optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Tom Lane <tgl@sss.pgh.pa.us>
Re: optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Tom Lane <tgl@sss.pgh.pa.us>
Re: optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Bruce Momjian <pgman@candle.pha.pa.us>
Re: optimizing Postgres queries Tom Lane <tgl@sss.pgh.pa.us>
Re: optimizing Postgres queries David Teran <david.teran@cluster9.com>
Re: optimizing Postgres queries Rod Taylor <pg@rbt.ca>
Re: optimizing Postgres queries Christopher Kings-Lynne <chriskl@familyhealth.com.au>
Hi Shridhar,

> Are you sure you are using correct data types on indexes?
>
Did not know about this...

> e.g. if field1 is an int2 field, then following query would not use an 
> index.
>
our fk have the type bigint, when i try one simple select like this:

explain analyze SELECT --columns-- FROM KEY_VALUE_META_DATA t0 WHERE 
t0.ID_FOREIGN_TABLE = 21110;

i see that no index is being used whereas when i use

explain analyze SELECT --columns-- FROM KEY_VALUE_META_DATA t0 WHERE 
t0.ID_FOREIGN_TABLE = 21110::bigint;

an index is used. Very fine, the performance is about 10 to 100 times 
faster for the single select.

I am using WebObjects with JDBC. I will now create a DB with integer 
instead of bigint and see how this performs.

regards David

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