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Posted to user-java@ibatis.apache.org by Michael Schall <mi...@gmail.com> on 2009/07/21 23:00:54 UTC
Prepared Statement cache
We run are running iBATIS within WebSphere 6.1 on Windows using JNDI against
a DB2 database. During a performance tuning session we found a query using
an index that did not have a vital column. We added the missing column to
the end of the index on a test database and using a db2 query analyzer we
saw a big performance gain. We moved the index to our production servers
and see similar gains using db2 tools, however we do not see the benefit in
the WebSphere application. How/Where are are prepared statements cached and
how can I clear them to get a plan that takes advantage of the new index.
Thanks
Mike
Re: Prepared Statement cache
Posted by Nicholoz Koka Kiknadze <ki...@gmail.com>.
Maybe I'm totally wrong, but I'm almost sure it must be possible to force
database server to RE-generate execution plans even for cached statements.
I've never used DB2 but googling a little I found:
http://publib.boulder.ibm.com/infocenter/dzichelp/v2r2/index.jsp?topic=/com.ibm.db29.doc.ugref/db2z_invalidatestatementscache.htm
HTH
Re: Prepared Statement cache
Posted by Mario Ds Briggs <ma...@in.ibm.com>.
The statement cache is configured on the Data Source properties in WAS. You
probably want to check with your WAS admin what's the minimal way of
flushing it without bouncing WAS itself ( bouncing the app alone wont help)
Mario
Michael Schall
<mike.schall@gmai
l.com> To
user-java@ibatis.apache.org
22/07/2009 03:38 cc
Subject
Please respond to Re: Prepared Statement cache
user-java@ibatis.
apache.org
Anyway to just tell the webservers (I assume JNDI) to drop all prepared
statements?
On Tue, Jul 21, 2009 at 4:09 PM, Glenn Barnard <ba...@gmail.com>
wrote:
restart your webservers!
On Tue, Jul 21, 2009 at 5:00 PM, Michael Schall <mi...@gmail.com>
wrote:
We run are running iBATIS within WebSphere 6.1 on Windows using JNDI
against a DB2 database. During a performance tuning session we found a
query using an index that did not have a vital column. We added the
missing column to the end of the index on a test database and using a
db2 query analyzer we saw a big performance gain. We moved the index to
our production servers and see similar gains using db2 tools, however we
do not see the benefit in the WebSphere application. How/Where are are
prepared statements cached and how can I clear them to get a plan that
takes advantage of the new index.
Thanks
Mike
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Re: Prepared Statement cache
Posted by Michael Schall <mi...@gmail.com>.
Anyway to just tell the webservers (I assume JNDI) to drop all prepared
statements?
On Tue, Jul 21, 2009 at 4:09 PM, Glenn Barnard <ba...@gmail.com>wrote:
> restart your webservers!
>
>
> On Tue, Jul 21, 2009 at 5:00 PM, Michael Schall <mi...@gmail.com>wrote:
>
>> We run are running iBATIS within WebSphere 6.1 on Windows using JNDI
>> against a DB2 database. During a performance tuning session we found a
>> query using an index that did not have a vital column. We added the missing
>> column to the end of the index on a test database and using a db2 query
>> analyzer we saw a big performance gain. We moved the index to our
>> production servers and see similar gains using db2 tools, however we do not
>> see the benefit in the WebSphere application. How/Where are are prepared
>> statements cached and how can I clear them to get a plan that takes
>> advantage of the new index.
>> Thanks
>>
>> Mike
>>
>
>
Re: Prepared Statement cache
Posted by Glenn Barnard <ba...@gmail.com>.
restart your webservers!
On Tue, Jul 21, 2009 at 5:00 PM, Michael Schall <mi...@gmail.com>wrote:
> We run are running iBATIS within WebSphere 6.1 on Windows using JNDI
> against a DB2 database. During a performance tuning session we found a
> query using an index that did not have a vital column. We added the missing
> column to the end of the index on a test database and using a db2 query
> analyzer we saw a big performance gain. We moved the index to our
> production servers and see similar gains using db2 tools, however we do not
> see the benefit in the WebSphere application. How/Where are are prepared
> statements cached and how can I clear them to get a plan that takes
> advantage of the new index.
> Thanks
>
> Mike
>