sqlite3 performance problems only in python

[Che M]

On Jul 23, 3:58 pm, Stef Mientki <stef.mien... at gmail.com> wrote:
> Piet van Oostrum wrote:
> >>>>>> Stef Mientki <stef.mien... at gmail.com> (SM) wrote:
>
> >> SM> btw, I don't know if it's of any importance, the SQL-statement I perform is
> >> SM> select OPNAMEN.*, NAME, NAME_, SCORES.SCORE, PATIENT.*
> >> SM>  from OPNAMEN
> >> SM>    inner join POID_VLID          on OPNAMEN.POID            = POID_VLID.POID
> >> SM>    inner join VRAAGLST           on VRAAGLST.VLID           = POID_VLID.VLID
> >> SM>    inner join VLID_SSID          on VRAAGLST.VLID           = VLID_SSID.VLID
> >> SM>    inner join SUBSCHAAL_GEGEVENS on SUBSCHAAL_GEGEVENS.SSID = VLID_SSID.SSID
> >> SM>    inner join POID_SSID_SCID     on ( OPNAMEN.POID            =
> >> SM> POID_SSID_SCID.POID ) and
> >> SM>                                     ( SUBSCHAAL_GEGEVENS.SSID =
> >> SM> POID_SSID_SCID.SSID )
> >> SM>    inner join SCORES             on SCORES.SCID             =
> >> SM> POID_SSID_SCID.SCID
> >> SM>    inner join PID_POID           on OPNAMEN.POID            = PID_POID.POID
> >> SM>    inner join PATIENT            on PATIENT.PID             = PID_POID.PID
> >> SM>  where substr ( lower( NAME) , 1, 6)  = 'cis20r'
> >> SM>    and lower ( NAME_ ) = 'fatigue'
> >> SM>    and TEST_COUNT in (3,4)
> >> SM>    and DATETIME > 39814.0
> >> SM>    and SCORE < 30
>
> > 1) Do you have indices on the join fields?
>
> well I'm happily surprised, you came up with this suggestion
> - I thought that sqlite created indexes on all primairy key and unique
> fields
> - but after explicitly creating the indices, a gained a speed of about a
> factor 10
> After checking the database creation, it seemed I forgot to make these
> fields the primary key
> so thanks very much.
>
> I gained another factor of 10 speed by updating to version 2.5.5 of
> pysqlite.
>
> cheers,
> Stef
>
> > 2) Look at the ANALYZE command
> > 3) Look at the EXPLAIN command
>
>

You might want to consult the SQLite list for questions like this.

Why do you use pysqlite?  I just import sqlite3 in Python 2.5.
What is the advantage of pysqlite?

Che