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From Francois Orsini <francois.ors...@gmail.com>
Subject Re: any explanation of pointbase performance in results posted in DERBY-465? Do they automatically create indexes?
Date Wed, 20 Jul 2005 21:54:34 GMT
Pointbase keeps track of the execution plan information for a query
into 2 tables named PLAN_QUERIES and PLAN_TABLE (private to the
current user) - it would be interesting to see what plan has been
chosen for the concerned queries...

The PLAN_TABLE table will indicate if an index has been used for a
particular query ID...

You could also issue:

SET PLANONLY ON | OFF (to generate execution plan only)
 
_or_

SET SHOWPLAN ON | OFF (to display the plan)

For such a simple query, creating an index dynamically could be a real
hit depending on the number of rows, etc...never heard of it,
especially as this is not a range query....

--francois

On 7/20/05, Mike Matrigali <mikem_app@sbcglobal.net> wrote:
> The results posted in DERBY-465 seem to indicate that somehow
> pointbase can execute select * from table where nonkey=5000 at
> a constant performance no matter how many rows in the table with
> no index on "nonkey".
> 
> Not surprisingly derby performance on this query is linearly
> related to the size of the table with no index.  Performance is
> constant when an index is added.
> 
> Does anyone know if pointbase somehow automatically creates
> and maintains indexes, maybe as directed by the optimizer?
>

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