Hi,

> unfortunatly put an index on fieldA and another on fieldB not help ! same speed (or i miss
> something, i probably write badly the query plan ?)

Could (or may be you already do) also test the difference between the time for the "index builds"
and "fetch time".

What is the difference in speed between (with an index on FieldA and an index on FieldB)

SELECT
FIRST 1 *
FROM
TableX x
WHERE
x.FieldA > 1 and x.FieldA < 10000000 and
x.FieldB > 5 and x.FieldB < 6

and

SELECT
*
FROM
TableX x
WHERE
x.FieldA > 1 and x.FieldA < 10000000 and
x.FieldB > 5 and x.FieldB < 6

Do you always need to fetch all rows?

Which Firebird version are you using?

Regards,
Arno Brinkman
ABVisie
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

General database development support:
http://www.databasedevelopmentforum.com

Firebird open source database (based on IB-OE) with many SQL-99 features :
http://www.firebirdsql.org
http://www.firebirdsql.info
http://www.fingerbird.de/
http://www.comunidade-firebird.org/

Support list for Firebird and Interbase users :
firebird-support@yahoogroups.com

Nederlandse firebird nieuwsgroep :
news://newsgroups.firebirdsql.info