Re: View not using index - Mailing list pgsql-performance

rvponp=# explain select * from vw_document_pagesperjob ;

                                       QUERY PLAN

----------------------------------------------------------------------------------------

 Subquery Scan vw_document_pagesperjob  (cost=82796.59..90149.20
rows=588209 width=706)

   ->  Sort  (cost=82796.59..84267.11 rows=588209 width=74)

         Sort Key: tblprintjobs.descpages, tblprintjobs.documentname

         ->  Seq Scan on tblprintjobs  (cost=0.00..26428.61
rows=588209 width=74)

(4 rows)


rvponp=# explain select * from vw_document_pagesperjob limit 10 ;

                                          QUERY PLAN

----------------------------------------------------------------------------------------------

 Limit  (cost=82796.59..82796.72 rows=10 width=706)

   ->  Subquery Scan vw_document_pagesperjob  (cost=82796.59..90149.20
rows=588209 width=706)

         ->  Sort  (cost=82796.59..84267.11 rows=588209 width=74)

               Sort Key: tblprintjobs.descpages,
tblprintjobs.documentname

               ->  Seq Scan on tblprintjobs  (cost=0.00..26428.61
rows=588209 width=74)

(5 rows)


rvponp=# explain select documentname, eventdate, eventtime, loginuser,
pages from tblPrintjobs order

by descpages, documentname ;

                                 QUERY PLAN

----------------------------------------------------------------------------

 Sort  (cost=81326.07..82796.59 rows=588209 width=74)

   Sort Key: descpages, documentname

   ->  Seq Scan on tblprintjobs  (cost=0.00..24958.09 rows=588209
width=74)

(3 rows)


rvponp=# explain select documentname, eventdate, eventtime, loginuser,
pages from tblPrintjobs order

by descpages, documentname limit 10 ;

                                                 QUERY PLAN

-------------------------------------------------------------------------------------------------------------

 Limit  (cost=0.00..33.14 rows=10 width=74)

   ->  Index Scan using ixprintjobspagesperjob on tblprintjobs
(cost=0.00..1949116.68 rows=588209 width=74)

(2 rows)



<fixed><x-tad-bigger>create or replace view vw_document_pagesperjob as

    select documentname, eventdate, eventtime, loginuser,

        fnFormatInt(pages) as pages

    from tblPrintjobs

    order by descpages, documentname ;

</x-tad-bigger></fixed>






On 13 Jun 2005, at 09:05, Russell Smith wrote:


<excerpt>On Mon, 13 Jun 2005 04:54 pm, Yves Vindevogel wrote:

<excerpt>Still, when I use explain, pg says it will first sort my
tables instead

of using my index

How is that possible ?

</excerpt>

Can we see the output of the explain analyze?

The definition of the view?


Regards


Russell Smith



</excerpt>Met vriendelijke groeten,

Bien à vous,

Kind regards,


<bold>Yves Vindevogel</bold>

<bold>Implements</bold>

<smaller>

</smaller>rvponp=# explain select * from vw_document_pagesperjob ;
                                        QUERY PLAN
------------------------------------------------------------------------
----------------
  Subquery Scan vw_document_pagesperjob  (cost=82796.59..90149.20
rows=588209 width=706)
    ->  Sort  (cost=82796.59..84267.11 rows=588209 width=74)
          Sort Key: tblprintjobs.descpages, tblprintjobs.documentname
          ->  Seq Scan on tblprintjobs  (cost=0.00..26428.61 rows=588209
width=74)
(4 rows)

rvponp=# explain select * from vw_document_pagesperjob limit 10 ;
                                           QUERY PLAN
------------------------------------------------------------------------
----------------------
  Limit  (cost=82796.59..82796.72 rows=10 width=706)
    ->  Subquery Scan vw_document_pagesperjob  (cost=82796.59..90149.20
rows=588209 width=706)
          ->  Sort  (cost=82796.59..84267.11 rows=588209 width=74)
                Sort Key: tblprintjobs.descpages,
tblprintjobs.documentname
                ->  Seq Scan on tblprintjobs  (cost=0.00..26428.61
rows=588209 width=74)
(5 rows)

rvponp=# explain select documentname, eventdate, eventtime, loginuser,
pages from tblPrintjobs order
by descpages, documentname ;
                                  QUERY PLAN
------------------------------------------------------------------------
----
  Sort  (cost=81326.07..82796.59 rows=588209 width=74)
    Sort Key: descpages, documentname
    ->  Seq Scan on tblprintjobs  (cost=0.00..24958.09 rows=588209
width=74)
(3 rows)

rvponp=# explain select documentname, eventdate, eventtime, loginuser,
pages from tblPrintjobs order
by descpages, documentname limit 10 ;
                                                  QUERY PLAN
------------------------------------------------------------------------
-------------------------------------
  Limit  (cost=0.00..33.14 rows=10 width=74)
    ->  Index Scan using ixprintjobspagesperjob on tblprintjobs
(cost=0.00..1949116.68 rows=588209 width=74)
(2 rows)


create or replace view vw_document_pagesperjob as
    select documentname, eventdate, eventtime, loginuser,
        fnFormatInt(pages) as pages
    from tblPrintjobs
    order by descpages, documentname ;






On 13 Jun 2005, at 09:05, Russell Smith wrote:

> On Mon, 13 Jun 2005 04:54 pm, Yves Vindevogel wrote:
>> Still, when I use explain, pg says it will first sort my tables
>> instead
>> of using my index
>> How is that possible ?
>
> Can we see the output of the explain analyze?
> The definition of the view?
>
> Regards
>
> Russell Smith
>
>
Met vriendelijke groeten,
Bien à vous,
Kind regards,

Yves Vindevogel
Implements

<smaller>


Mail: yves.vindevogel@implements.be  - Mobile: +32 (478) 80 82 91


Kempische Steenweg 206 - 3500 Hasselt - Tel-Fax: +32 (11) 43 55 76


Web: http://www.implements.be

<italic><x-tad-smaller>

First they ignore you.  Then they laugh at you.  Then they fight you.
Then you win.

Mahatma Ghandi.</x-tad-smaller></italic></smaller>



Mail: yves.vindevogel@implements.be  - Mobile: +32 (478) 80 82 91

Kempische Steenweg 206 - 3500 Hasselt - Tel-Fax: +32 (11) 43 55 76

Web: http://www.implements.be

First they ignore you.  Then they laugh at you.  Then they fight you.
Then you win.
Mahatma Ghandi.