Re: Confirmation of bad query plan generated by 7.4

From: "Shaun Thomas" <sthomas(at)leapfrogonline(dot)com>
To: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>,"Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Subject: Re: Confirmation of bad query plan generated by 7.4
Date: 2006-06-13 22:41:06
Message-ID: 448EF8B2.8F27.00A9.0@leapfrogonline.com
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>>> On 6/13/2006 at 4:54 PM, "Jim C. Nasby" <jnasby(at)pervasive(dot)com>
wrote:

> SELECT attname, attstattarget
> FROM pg_attribute
> WHERE attrelid='table_name'::regclass AND attnum >= 0;

-1 for all values.

> SHOW default_statistics_target;

10.

Here's something slightly annoying: I tried precalculating the value
in my stored proc, and it's still ignoring it.

lastTime := now() - interval ''7 days'';

UPDATE fact_credit_app
SET activated_date_id = ad.date_id
FROM l_event_log e
JOIN c_event_type t ON (t.id = e.event_type_id)
JOIN wf_date ad ON (e.event_date::date=ad.datestamp)
WHERE e.ext_id=fact_credit_app.unique_id
AND t.event_name = ''activation''
AND e.event_date > lastTime
AND fact_credit_app.activated_date_id IS NULL;

Instead of taking a handful of seconds (like when I replace
lastTime with the text equivalent), it takes 10 minutes...
I can see the planner not liking the results of a function,
but a variable? That's a static value! ::cry::

--

Shaun Thomas
Database Administrator

Leapfrog Online
807 Greenwood Street
Evanston, IL 60201
Tel. 847-440-8253
Fax. 847-570-5750
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