Re: Perfrmance Problems (7.4.6)

Ok. But that means I need a trigger on the original column to update the
new column on each insert/update and that overhead.

-----Original Message-----
From: Ruben Rubio Rey [mailto:ruben@rentalia.com]
Sent: Thursday, April 20, 2006 12:49 PM
To: Doron Baranes; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Perfrmance Problems (7.4.6)

I think that the problem is the GROUP BY (datetime) that is
date_trunc('hour'::text, i.entry_time)
You should create an indexe with this expression (if its possible).

http://www.postgresql.org/docs/7.4/interactive/indexes-expressional.html

If is not possible, I would create a column with value
date_trunc('hour'::text, i.entry_time) of each row and then index it.

Hope this helps :)

Doron Baranes wrote:

>Hi,
>
>I am running on postgres 7.4.6.
>I did a vacuum analyze on the database but there was no change.
>I Attached here a file with details about the tables, the queries and
>the Explain analyze plans.
>Hope this can be helpful to analyze my problem
>
>10x
>Doron
>
>
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>TIP 9: In versions below 8.0, the planner will ignore your desire to
>       choose an index scan if your joining column's datatypes do not
>       match
>
>