Its not necessary to add a plan, the firebird engine is pretty good at
selecting the best one. Many years ago I remember reading that you can
suggest a plan, but the engine might use what it wants. :-) I dont
know if its true, but it was in of the documents.

Rohit

On 5/10/2012 1:37 a.m., patrick_marten wrote:
>
> Hello,
>
> I'm using an IB_Cursor to obtain some data for statistics. These data
> can be viewed in different way (grouped on different fields).
> Additionally several filter criterias can be applied, depending on
> what the user would like to do.
>
> I'm checking all this and build my SQL statement. In order to increase
> performance, I'm using query plan, but sometimes it's causing
> problems, it seems.
>
> Depending on the final statement, query plan can differ - at least
> that's what I see in IBXpert or other tools. I'd copied it and added
> it to the cursor at the end. Mostly it seemed to work with this single
> plan string for all cases, but recently I'm getting some errors sometimes:
> "unsuccessful metadata update
> request depth exceeded. (Recursive definition?)"
>
> Once I remove the plan string, everything works fine.
>
> Is it neccessary at all, to add a plan string? That's what I thought
> because of the performance.
>
> If that's correct: is there a way to determine a correct plan string
> for each SQL statement (automatically)? There are just too many
> constellations how the SQL statement could be, depending on the
> criterias defined by the user...
>
> Best regards,
> Patrick
>
>
>
>
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--
Regards

*Rohit Gupta*
B.E. Elec., M.E., Mem IEEE, Member IET
Technical Director
Computer Fanatics Ltd

*Tel *4892280
*Fax *4892290
*Web *www.cfl.co.nz
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