Thread: Using LIKE expression problem..

Using LIKE expression problem..

From
"Michael Ryan S. Puncia"
Date:

Hi everybody..

   

     Before anything else I would like to thank all those person who answers my previous question… again thank you very much

 

This is my question …

   

     In my query .. Select * from table1 where lastname LIKE  ‘PUNCIA%’..

 

In the query plan ..it uses seq scan rather than index scan .. why ? I have index on lastname, firtname…

 

 

Thanks

Re: Using LIKE expression problem..

From
Christopher Kings-Lynne
Date:
> In the query plan ..it uses seq scan rather than index scan .. why ? I
> have index on lastname, firtname…

Have you run VACUUM ANALYZE; on the table recently?

Chris


Re: Using LIKE expression problem..

From
"Michael Ryan S. Puncia"
Date:
Yes , I already do that but the same result .. LIKE uses seq scan

-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Christopher
Kings-Lynne
Sent: Wednesday, May 12, 2004 2:48 PM
To: Michael Ryan S. Puncia
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Using LIKE expression problem..

> In the query plan ..it uses seq scan rather than index scan .. why ? I
> have index on lastname, firtname.

Have you run VACUUM ANALYZE; on the table recently?

Chris


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Re: Using LIKE expression problem..

From
Christopher Kings-Lynne
Date:
Are you in a non-C locale?

Chris

Michael Ryan S. Puncia wrote:

> Yes , I already do that but the same result .. LIKE uses seq scan
>
> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Christopher
> Kings-Lynne
> Sent: Wednesday, May 12, 2004 2:48 PM
> To: Michael Ryan S. Puncia
> Cc: pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] Using LIKE expression problem..
>
>
>>In the query plan ..it uses seq scan rather than index scan .. why ? I
>>have index on lastname, firtname.
>
>
> Have you run VACUUM ANALYZE; on the table recently?
>
> Chris
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
>

Re: Using LIKE expression problem..

From
"Michael Ryan S. Puncia"
Date:
Sorry .. I am a newbie and I don't know :(
How can I know that I am in C locale ?
How can I change my database to use C locale?



-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Christopher
Kings-Lynne
Sent: Wednesday, May 12, 2004 3:59 PM
To: Michael Ryan S. Puncia
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Using LIKE expression problem..

Are you in a non-C locale?

Chris

Michael Ryan S. Puncia wrote:

> Yes , I already do that but the same result .. LIKE uses seq scan
>
> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Christopher
> Kings-Lynne
> Sent: Wednesday, May 12, 2004 2:48 PM
> To: Michael Ryan S. Puncia
> Cc: pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] Using LIKE expression problem..
>
>
>>In the query plan ..it uses seq scan rather than index scan .. why ? I
>>have index on lastname, firtname.
>
>
> Have you run VACUUM ANALYZE; on the table recently?
>
> Chris
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: don't forget to increase your free space map settings
>

---------------------------(end of broadcast)---------------------------
TIP 5: Have you checked our extensive FAQ?

               http://www.postgresql.org/docs/faqs/FAQ.html



Re: Using LIKE expression problem..

From
Joseph Shraibman
Date:
Use the text_pattern_ops operator when creating the index, see:
http://www.postgresql.org/docs/7.4/static/indexes-opclass.html

Michael Ryan S. Puncia wrote:
> Sorry .. I am a newbie and I don't know :(
> How can I know that I am in C locale ?
> How can I change my database to use C locale?
>
>
>
> -----Original Message-----
> From: pgsql-performance-owner@postgresql.org
> [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Christopher
> Kings-Lynne
> Sent: Wednesday, May 12, 2004 3:59 PM
> To: Michael Ryan S. Puncia
> Cc: pgsql-performance@postgresql.org
> Subject: Re: [PERFORM] Using LIKE expression problem..
>
> Are you in a non-C locale?
>
> Chris
>
> Michael Ryan S. Puncia wrote:
>
>
>>Yes , I already do that but the same result .. LIKE uses seq scan
>>
>>-----Original Message-----
>>From: pgsql-performance-owner@postgresql.org
>>[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Christopher
>>Kings-Lynne
>>Sent: Wednesday, May 12, 2004 2:48 PM
>>To: Michael Ryan S. Puncia
>>Cc: pgsql-performance@postgresql.org
>>Subject: Re: [PERFORM] Using LIKE expression problem..
>>
>>
>>
>>>In the query plan ..it uses seq scan rather than index scan .. why ? I
>>>have index on lastname, firtname.
>>
>>
>>Have you run VACUUM ANALYZE; on the table recently?
>>
>>Chris
>>
>>
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>>
>
>
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>
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>
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