i just setup the default fbtrace.conf with all item to true, but i don't have any usefull informations ...

just this when i commit :

0 ms, 1 read(s), 1 write(s), 1 fetch(es), 1 mark(s)

ex :

-------------------------------------------------------------------------------
select
IDObj
From
desc_blob
where
IDObj='NOT_EXIST'
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
PLAN (DESC_BLOB INDEX (DESC_BLOB_IDX))
34 ms



select
IDObj
From
desc_empty
where
IDObj='NOT_EXIST'
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
PLAN (DESC_EMPTY INDEX (DESC_EMPTY_IDX))
2 ms

--- In firebird-support@yahoogroups.com, Thomas Steinmaurer <ts@...> wrote:
>
> > THE DDL of the 3 sample table :
> >
> > CREATE TABLE DESC_VARCHAR (
> > IDOBJ VARCHAR(20),
> > COMMENT VARCHAR(10000)
> > );
> > CREATE INDEX DESC_VARCHAR_IDX ON DESC_VARCHAR(IDOBJ);
> >
> > ********
> >
> > CREATE TABLE DESC_BLOB (
> > IDOBJ VARCHAR(20)
> > COMMENT BLOB
> > );
> > CREATE INDEX DESC_BLOB_IDX ON DESC_BLOB(IDOBJ);
> >
> > ********
> >
> > CREATE TABLE DESC_EMPTY (
> > IDOBJ VARCHAR(20)
> > );
> > CREATE INDEX DESC_EMPTY_IDX ON DESC_EMPTY(IDOBJ);
> >
> >
> > tables are newly created and filled with the exact same reccords (40 millions rows)
> >
> > the same query on the 3 tables :
> >
> > select IDObj From desc_varchar where IDObj='NOT_EXIST';
> > PLAN (DESC_VARCHAR INDEX (DESC_VARCHAR_IDX))
> > => around 430 ms to return
> >
> > select IDObj From desc_blob where IDObj='NOT_EXIST'
> > PLAN (DESC_BLOB INDEX (DESC_BLOB_IDX))
> > => around 350 ms to return
> >
> > select IDObj From desc_xxxx where IDObj='NOT_EXIST'
> > PLAN (DESC_EMPTY INDEX (DESC_EMPTY_IDX))
> > => around 1.5 ms to return
> >
> >
> > if you understand something ..... moving the page size from 8 to 16 reduce by 10 the speed of the 2 first query, but still 10x more slower than the last variante
>
> If you are using Firebird 2.5, use the Trace API to get some IO
> statistics per executed statement.
>
>
> --
> With regards,
> Thomas Steinmaurer (^TS^)
> Firebird Technology Evangelist
>
> http://www.upscene.com/
>
> Do you care about the future of Firebird? Join the Firebird Foundation:
> http://www.firebirdsql.org/en/firebird-foundation/
>