Date: Tue, 20 May 2008 08:15:48 +0200
From: "A. Kretschmer" <andreas.kretschmer@schollglas.com>
To: pgsql-performance@postgresql.org
Subject: Re: slow update
Message-ID: <20080520061548.GA29403@a-kretschmer.de>
References: <468CEDC5-0707-4C5F-880F-45A75330731A@kevinkempterllc.com>
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In-Reply-To: <468CEDC5-0707-4C5F-880F-45A75330731A@kevinkempterllc.com>
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am  Mon, dem 19.05.2008, um 23:56:27 -0600 mailte kevin kempter folgendes:
> Hi all;
> 
> I have a query that does this:
> 
> update tab_x set (inactive_dt, last_update_dt) =
> ((select run_dt from current_run_date), (select run_dt from  
> current_run_date))
> where
> cust_id::text || loc_id::text in
> (select cust_id::text || loc_id::text from summary_tab);
> 
> 
> The current_run_date table has only 1 row in it
> the summary_tab table has 0 rows and the tab_x had 450,000 rows
> 
> The update takes 45min even though there is no rows to update.
> I have a compound index (cust_id, loc_id) on both tables (summary_tab  
> and tab_x)
> 
> How can I speed this up ?

Please show us more details, for instance the data-types for cust_id and
loc_id. Wild guess: these columns are INT-Values and you have an Index.
Okay, but in the quere there is a CAST to TEXT -> Index not used.

Verfify this with EXPLAIN.


Andreas
-- 
Andreas Kretschmer
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