David Van Couvering wrote:
Yes, Stanley's answer is my understanding too. Please do close
prepared statements.
OK. So I will make sure to explictly close all PreparedStatements in
finally blocks and not rely on Connection.close() so as to avoid:
http://issues.apache.org/jira/browse/DERBY-210
One more related question. Are there known memory leaks if my
application also does not close regular Statements (as opposed to
PreparedStatements)
and relies on Connection.close()?
BTW recall I run within an Sun AppServer 8.2 environment which does
ConnectionPooling and there for does not actually
close the Connection on Connection.close().
Thanks for your help.
David
Stanley Bradbury wrote:
Farrukh Najmi wrote:
My application uses Derby 10.1 in a derby client that is a servlet
running within a Servlet Container (typically Sun Java Application
Srever 8.2 a.k.a AS or Tomcat 5.0.x).
We use PreparedStatement quite a bit. I would like to know what we
can do to maximize reuse of PreparedStatement optimization plan
within Derby.
Whose job is it to do PreparedStatement pooling?
Is is Derby's or the container (AS / Tomcat)?
What can we do do maximize leverage of PreparedStatement caching in
my configurations?
BTW We do not typically close our PreparedStatement basedon the
possibly faulty assumption that this would remove the
PreparedStatement form the PreparedStatement cache. We instead rely
on Connection.close() to take care of doing whatever closing is
needed to be done. Is this a bad practice?
Above practice has led us into trouble with the following known
Derby issue:
http://issues.apache.org/jira/browse/DERBY-210
It seems the workaround is to close all PreparedStatements explicitly.
If we do that will it remove PreparedStatement that is being closed
from the PreparedStatement cache?
Thanks for any guidance on this.
Hi Frank -
Plans in the PreparedStatement cache in Derby are only removed when
they age out, that is: the plans will be maintained in cache for use
until:
Additional space is needed for a newly created PreparedStatement AND
The plan is the Least Recently Used in the cache
It is unlikely that a PreparedStatement that has seen recent use will
be removed for the cache. So, to put it briefly, let Derby cache the
plans and DO close the PreparedStatements when it is no longer needed
by the routine.
--
Regards,
Farrukh
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