query gone haywire :)

From: Robin Ericsson <robin(dot)ericsson(at)profecta(dot)se>
To: Postgres general mailing list <pgsql-general(at)postgresql(dot)org>
Subject: query gone haywire :)
Date: 2004-10-08 09:19:57
Message-ID: 1097227197.7088.90.camel@pylver.localhost.nu.
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The query have been running ok for some time now, but this morning I
decided to run vacuum analyze (vacuumdb -a -z) on the cluster, and
suddenly the query isn't running very well at all. This query has only
one value in the "IN", if I add another id the query becomes really
really slow.

Query:
SELECT
data.entered,
data.machine_id,
datatemplate_intervals.template_id,
data_values.value
FROM
data, data_values, datatemplate_intervals
WHERE
datatemplate_intervals.id = data_values.template_id AND
data_values.data_id = data.id AND
data.machine_id IN (2) AND
current_timestamp::timestamp - interval '60 seconds' < data.entered

Indexes exists on data_values.template_id, data.entered,
data.machine_id, datatemplate_intervals.machine_id,
datatemplate_intervals.template_id.

Data contains almost 1.5milj entries, and data_values around 9.1milj. As
I write this letter I check the tables in pgAdmin, and it tells me this
for table data """
Rows (estimated) 1
Rows (counted) 1491401
""" even though I run vacuum analyze on the table itself from pgadmin.

Explain analyze result attached as explain-analyze.txt

Explain without analyze when using IN(2,3) attached as explain.txt

Regards,
Robin

Attachment Content-Type Size
explain-analyze.txt text/plain 1018 bytes
explain.txt text/plain 886 bytes

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