Hi Ken,
Thanks for reply.
1.
The problem is that using 'now' in VIEW, the resulting VIEW will hard code the
current timestamp.
It is not dynamic.
If I use write the view like this:
WHERE food.post_timestamp >= ('now'::date - interval '1 month')::timestamp
without time zone
AND food.post_timestamp <= 'now'::timestamp without time zone
The VIEW will be created like this:
WHERE food.post_timestamp >= ('2014-08-21'::date - '1 mon'::interval) AND
food.post_timestamp <= '2014-08-21 17:32:21.787179'::timestamp without time zone
2.
now() is dynamic but it scan all the partitioned tables.
Thanks and regards,
Patrick
On Thursday, August 21, 2014 4:27 PM, Ken Tanzer <[email protected]> wrote:
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;
I think the problem is that you're using 'now'::date in your first example,
which gets frozen. You can use now() or current_timestamp or current_date to
get dynamic results.
CREATE VIEW test_now AS SELECT current_timestamp as current_ts, now() as
now_function,'now'::timestamp AS now_literal;
(wait a couple of seconds)
SELECT * FROM test_now;
current_ts | now_function |
now_literal
-------------------------------+-------------------------------+----------------------------
2014-08-21 01:25:54.147004-07 | 2014-08-21 01:25:54.147004-07 | 2014-08-21
01:18:22.207073
(1 row)
You'll see that the last column is frozen while the other two stay current.
Cheers,
Ken
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