pokka_chi wrote:

> I am running a large db (around 4GB size) on FB2.0.1. I have a table
> around 1 million records with a primary key of 3 integer fields (say A,
> B, C). When I try to load a batch of records (say 10) starting from a
> particular record (e.g. A=1, B=2, C=3), I use the query:
>
> select first 10 * from MyTable where A>1 or (A=1 and (B>2 or (B=2 and
> C>=3))) order by A, B, C
>
> Sometimes, it is very fast but sometimes it is very slow. I've tried
> eliminating other factors (e.g. network) by running it in a standalone
> PC. I have also tried to force the plan by adding the clause
>
> PLAN(DOC ORDER PK INDEX(PK, PK)) // note: PK is the primary key's name
>
> The performance is still unpredictible. I have also checked the plan
> used in those cases of slow performance and it is using index.
>
> Usually when the query is executed the first time, it is slow. It is
> very fast when it is executed the second time. It seems that FB uses a
> lot of time to determine to use the index at the first time.
>

Won't be the Cache (FB or OS) entering the game ???

see you !

--
Alexandre Benson Smith
Development
THOR Software e Comercial Ltda
Santo Andre - Sao Paulo - Brazil
www.thorsoftware.com.br