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 | | From: | Andrei Bintintan | | Subject: | SQL timestamp to date cast | | Date: | Thu, 20 Jan 2005 10:52:50 +0200 |
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 | This is a multi-part message in MIME format.
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Content-Type: text/plain;
charset="iso-8859-1"
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Hi,=20
I have the following query:
SELECT DISTINCT(nummer) FROM user_action WHERE =
datetime::date=3D'11/11/2004' AND id_action IN (5,6,9)
Now, datetime has the type timestamp. How can I make an index or write =
different this query so that it runs faster? It really takes some time =
sometimes. Usually about 3-4secs. user_action has about 300k rows and =
increasing ~ 5-10k a day.=20
Explain analyze SELECT DISTINCT(nummer) FROM user_action WHERE =
datetime::date=3D'11/11/2004' AND id_action IN (5,6,9)
Unique (cost=3D18141.71..18143.72 rows=3D45 width=3D4) (actual =
time=3D418.122..418.340 rows=3D85 loops=3D1)
-> Sort (cost=3D18141.71..18142.72 rows=3D402 width=3D4) (actual =
time=3D418.119..418.194 rows=3D192 loops=3D1)
Sort Key: nummer
-> Seq Scan on user_action (cost=3D0.00..18124.33 rows=3D402 =
width=3D4) (actual time=3D366.240..417.890 rows=3D192 loops=3D1)
Filter: (((datetime)::date =3D '2004-11-11'::date) AND =
((id_action =3D 5) OR (id_action =3D 6) OR (id_action =3D 9)))
Total runtime: 418.419 ms
Best regards.
Andy.
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Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
charset=3Diso-8859-1">
Hi,
I have the following =
query:
SELECT DISTINCT(nummer) FROM =
user_action WHERE=20
datetime::date=3D'11/11/2004' AND id_action IN (5,6,9)
Now, datetime has the type timestamp. =
How can I=20
make an index or write different this query so that it runs faster? It =
really=20
takes some time sometimes. Usually about 3-4secs. user_action has about =
300k=20
rows and increasing ~ 5-10k a day. Explain size=3D2>analyze=20
SELECT DISTINCT(nummer) FROM user_action WHERE =
datetime::date=3D'11/11/2004' AND=20
id_action IN (5,6,9)
Unique (cost=3D18141.71..18143.72 =
rows=3D45=20
width=3D4) (actual time=3D418.122..418.340 rows=3D85 =
loops=3D1)
-> =20
Sort (cost=3D18141.71..18142.72 rows=3D402 width=3D4) (actual=20
time=3D418.119..418.194 rows=3D192=20
loops=3D1)
Sort Key:=20
nummer
-> Seq =
Scan on=20
user_action (cost=3D0.00..18124.33 rows=3D402 width=3D4) (actual=20
time=3D366.240..417.890 rows=3D192=20
loops=3D1)
=
; =20
Filter: (((datetime)::date =3D '2004-11-11'::date) AND ((id_action =3D =
5) OR=20
(id_action =3D 6) OR (id_action =3D 9)))
Total runtime: 418.419=20
ms
Best regards.
Andy.
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| | From: | Michael Fuhr | | Subject: | Re: SQL timestamp to date cast | | Date: | Thu, 20 Jan 2005 02:33:31 -0700 |
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| On Thu, Jan 20, 2005 at 10:52:50AM +0200, Andrei Bintintan wrote:
> SELECT DISTINCT(nummer)
> FROM user_action
> WHERE datetime::date='11/11/2004' AND id_action IN (5,6,9)
>
> Now, datetime has the type timestamp. How can I make an index or write
> different this query so that it runs faster?
You could create an index on datetime and rewrite your queries:
CREATE INDEX user_action_datetime_idx ON user_action (datetime);
SELECT DISTINCT(nummer)
FROM user_action
WHERE datetime >= '11/11/2004' AND datetime < '11/12/2004'
AND id_action IN (5,6,9);
Another possibility would be to create a functional index on datetime:
CREATE INDEX user_action_date_idx ON user_action (date(datetime));
SELECT DISTINCT(nummer)
FROM user_action
WHERE date(datetime) = '11/11/2004' AND id_action IN (5,6,9);
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/
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TIP 9: the planner will ignore your desire to choose an index scan if your
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| | From: | Andrei Bintintan | | Subject: | Re: SQL timestamp to date cast | | Date: | Thu, 20 Jan 2005 11:41:41 +0200 |
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| > Another possibility would be to create a functional index on datetime:
>
> CREATE INDEX user_action_date_idx ON user_action (date(datetime));
GREAT!!! I thought it is possible but I didn't knew how to make such
indexes. :))
Thank you !!!
Andy.
----- Original Message -----
From: "Michael Fuhr"
To: "Andrei Bintintan"
Cc:
Sent: Thursday, January 20, 2005 11:33 AM
Subject: Re: [SQL] SQL timestamp to date cast
> On Thu, Jan 20, 2005 at 10:52:50AM +0200, Andrei Bintintan wrote:
>
>> SELECT DISTINCT(nummer)
>> FROM user_action
>> WHERE datetime::date='11/11/2004' AND id_action IN (5,6,9)
>>
>> Now, datetime has the type timestamp. How can I make an index or write
>> different this query so that it runs faster?
>
> You could create an index on datetime and rewrite your queries:
>
> CREATE INDEX user_action_datetime_idx ON user_action (datetime);
>
> SELECT DISTINCT(nummer)
> FROM user_action
> WHERE datetime >= '11/11/2004' AND datetime < '11/12/2004'
> AND id_action IN (5,6,9);
>
> Another possibility would be to create a functional index on datetime:
>
> CREATE INDEX user_action_date_idx ON user_action (date(datetime));
>
> SELECT DISTINCT(nummer)
> FROM user_action
> WHERE date(datetime) = '11/11/2004' AND id_action IN (5,6,9);
>
> --
> Michael Fuhr
> http://www.fuhr.org/~mfuhr/
>
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| | From: | Michael Fuhr | | Subject: | Re: SQL timestamp to date cast | | Date: | Thu, 20 Jan 2005 02:51:16 -0700 |
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| On Thu, Jan 20, 2005 at 11:41:41AM +0200, Andrei Bintintan wrote:
> >Another possibility would be to create a functional index on datetime:
> >
> >CREATE INDEX user_action_date_idx ON user_action (date(datetime));
>
> GREAT!!! I thought it is possible but I didn't knew how to make such
> indexes. :))
See the "Indexes on Expressions" section in the "Indexes" chapter
of the documentation.
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/
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