From: | Patrick Dung <patrick_dkt(at)yahoo(dot)com(dot)hk> |
---|---|
To: | Pgsql-general General <pgsql-general(at)postgresql(dot)org> |
Subject: | Use of 'now' constant datatype in view to take advantage of partitioned table |
Date: | 2014-08-21 05:43:14 |
Message-ID: | 1408599794.24265.YahooMailNeo@web193505.mail.sg3.yahoo.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Hi Postgresql users,
I have a master table with two partition table (food_2013p, food_2014p).
I found that when I use SELECT + 'now' constant, constraint exclusion works, (it skipped the 2013 partition).
EXPLAIN ANALYZE
SELECT *
FROM food
WHERE food.post_timestamp >= ('now'::date - interval '1 month')::date AND food.post_timestamp <= 'now'
ORDER BY food.post_timestamp DESC
LIMIT 30;
But when I put the query inside view, 'now' is converted to the timestamp when I run the create view.
So the view becomes:
WHERE food.post_timestamp >= ('2014-08-21'::date - '1 mon'::interval)::date AND food.post_timestamp <= '2014-08-21 13:38:29.642347'::timestamp without time zone
This is not dynamic.
When I use now(), the query will scan other partition tables. I know this is a restriction of partition on non-immutable function.
Would it be possible or a feature request to take advantage of the partition table with query like this?
Thanks and regards,
Patrick
From | Date | Subject | |
---|---|---|---|
Next Message | Patrick Dung | 2014-08-21 07:20:24 | Re: Use of 'now' constant datatype in view to take advantage of partitioned table |
Previous Message | Jov | 2014-08-21 05:39:30 | Re: Linux replication to FreeBSD problem |