How to optimize the query

[David Zonsheine <Da...@enigma.com>]

Hello Derby Users
 
We are going to use Derby as an embedded data base for thousands of
applications we deliver to the market.
However, we have a simple database with a not so easy query that takes about
0.016 seconds in Oracle and 2.5 sec in Cloudscape (Derby).
I posted a question about hints and found out that there are no hints in
Derby right now.
We tried to see the index usage but couldn't.
 
How can I optimize a query in Derby? How do you do it? Is there a tool? Is
there a command line parameter?
 
Please help. We want to use this database.
 
David
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Re: How to optimize the query

[Sunitha Kambhampati <sk...@Yngvi.Org>]

David Zonsheine wrote:

> We tried to see the index usage but couldn't.
>
did you try to set the property derby.language.logQueryPlan=true in your 
derby.properties file or you can also set it as  a java property  
-Dderby.language.logQueryPlan=true

This property when set will print the query plans  in derby.log  

If an index is used, you will be able to see  IndexScan ResultSet....

an example :
here my tablename is SCANFIXED and index is SCANFIXEDX...

[snip]
    Index Scan ResultSet for SCANFIXED using index SCANFIXEDX at read 
committed isolation level using instantaneous share row locking chosen 
by the optimizer
[snip]


Sunitha.