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Optimizing the query

Mortin kim
Ranch Hand

Joined: Nov 15, 2007
Posts: 44
Please excuse me if these are dump questions.

How to optimize the SQL quereis for better performence.

How can we increase the database performence...?

Can we increse the connection pool size to any number..? How it will effect.?

Masoud Kalali
Ranch Hand

Joined: Jul 08, 2004
Posts: 531

Optimizing SQL statement can be done by looking at how you are using database objects: do you have well placed index, how you partition your tables, do you have appropriate views, how your database memory managed, fast is your hard disk and log hard disk,...

I think you should use an sql profiler or sql query plan analyzer which come with most of databases in order to check your sql statement performance.

But from the Java side you can make your JDBC code works better by using prepared statement where possible, Using correct mode of ResultSet, using batch commands, correct use of auto commit and manual commit, enabling database cache in different level like statement cache, managing JDBC objects correctly by closing them as soon as you can,..

You may increase the pool size to any number that your hardware/ software can accept but it will not guarantee any performance increase.

You should decide on your connection pool size at least based on the following items:
-Maximum number of concurrent database operations.
-Maximum possible time that a database operation may take to complete.
-Maximum time that a database request can be postponed until a connection become available

Masoud Kalali
Software Engineer - My Weblog - GlassFish Security
Ulf Dittmer

Joined: Mar 22, 2005
Posts: 42965
Regarding the pool size - increasing it may actually decrease DB performance, because more users can to access the DB simultaneously (which means each request would take longer to complete).
I agree. Here's the link:
subject: Optimizing the query
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