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From jaggee j <jaggee...@yahoo.com>
Subject RE: increase performance
Date Fri, 02 Sep 2005 09:33:05 GMT
Jean-Francois,
 
Thanks for the reply and agreed your comments.
We have also identified the SQL query optimization makes the big difference in the performance,so
we modifed the quries as much as possible.
 
Moreover,
1. we have not implemented the cache model till now,so we are planning to include this also,
the <select> statements have multiple loops with diffrent parameters.
what Type of Cache Model is best suited for this case.
 
2.this application only contains <select> statements .so if we use the cache model,
how to set flushOnExecute or how do flush the cache? 
 
3.Are lazyloading and  byte code enable improve the performance? 
 
i am finding difficult to decide these things , could any one help me ?
 
Thanks.

Jean-Francois Poilpret <jfpoilpret@hcm.vnn.vn> wrote:
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Hi,

 

>From what I can see, this is not in iBATIS that you should look for better performance
but in your SQL select statements.

It is always a bad idea, in a where clause, to use a function on an indexed column like in:

    SUBSTRING(NewLog_T.date,1,4) = #syukeiYear_# AND 



This way, the index will never be used: be prepared for a full table scan. If your table has
millions of rows, then you can go and take a coffee (maybe several) until the request is terminated.

 

So my advice is really to optimize your SQL (this might also require changing table structure
and adding indexes). Then when you could check its performance directly (I mean without iBATIS)
you can start (only if necessary, and I donft believe it would be) to think about iBATIS
optimizations.

 

Cheers

 

            Jean-Francois


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