Re: performance problem with 3-column indexes - Mailing list pgsql-hackers

From Stephan Szabo
Subject Re: performance problem with 3-column indexes
Date
Msg-id 20011107092420.V49204-100000@megazone23.bigpanda.com
Whole thread Raw
In response to performance problem with 3-column indexes  (czl@iname.com (charles))
List pgsql-hackers
Can you give an example query and explain output for both cases?
Have you run vacuum analyze?

Since I haven't seen the query, one thing that might bite you would
be if you aren't casting your constants to smallint, although I
don't know why that would change on the index definition.

On 6 Nov 2001, charles wrote:

> the table has about 30k records.
>     simple select statement, by primary key, requires plenty of cpu
> time when the primary key has three columns
>     when the primary key has two columns several times less cpu is
> required (even though the contents of the table is the same.
>
> so:
>    PRIMARY KEY(C_ID, C_D_ID, C_W_ID) -> PRIMARY KEY (C_ID, C_D_ID)
>            select cpu: 600           ->        select cpu 60
>



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