Hi,
I sent this to general earlier but I was redirected to performance.
The query have been running ok for quite some time, but after I did a
vacuum on the database, it's very very slow. This IN-query is only 2
ids. Before the problem that in was a subselect-query returning around
6-7 ids. The tables included in the query are described in database.txt.
status=# select count(id) from data;
count
---------
1577621
(1 row)
status=# select count(data_id) from data_values;
count
---------
9680931
(1 row)
I did run a new explain analyze on the query and found the attached
result. The obvious problem I see is a full index scan in
"idx_dv_data_id". I tried dropping and adding the index again, thats why
is't called "idx_data_values_data_id" in the dump.
status=# EXPLAIN ANALYZE
status-# SELECT
status-# data.entered,
status-# data.machine_id,
status-# datatemplate_intervals.template_id,
status-# data_values.value
status-# FROM
status-# data, data_values, datatemplate_intervals
status-# WHERE
status-# datatemplate_intervals.id = data_values.template_id AND
status-# data_values.data_id = data.id AND
status-# data.machine_id IN (2,3) AND
status-# current_timestamp::timestamp - interval '60 seconds' <
data.entered;
Regards,
Robin
--
Robin Ericsson <robin.ericsson@profecta.se>
Profecta HB
