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From David Smith <d...@cornell.edu>
Subject Re: JNDI/Tomcat question from newbie
Date Thu, 01 Sep 2005 14:46:39 GMT
Personally, I'd just keep a reference to the datasource around maybe as
a class instance variable.  It doesn't constitute a connection in and of
itself -- just a way of getting one from the pool.  Connections on the
other hand should be explicitly closed as soon as they aren't needed
anymore in any method that get's one.

--David

Hyatt, Gordon wrote:

>Hello All,
>
>I'm a newbie to database pooling via JNDI and I have a JNDI/Tomcat question (more of a
"best practices"/most scalable/fastest performance/least resource consumption type of question).
>
>Each time the JNDI resource (pooled database connection) is needed, should a complete
JNDI lookup be performed or can part of the lookup be "cached"?  For example, should the code
be:
>
><code>
>Context initCtx = new InitialContext ();
>Context envCtx = (Context)initCtx.lookup ("java:comp/env");
>ds = (DataSource)envCtx.lookup ("jdbc/data_source_name");
>
></code>
>
>or can the java:comp/env Context be saved as an attribute in the servlet context and a
(synchronized) code segment like the following be used to obtain the DataSource?
>
><code>
>Context ctx = (Context)ctxFromServletContext.lookup ("");
>ds = (DataSource)ctx.lookup ("jdbc/data_source_name");
></code>
>
>Thus far, I haven't read anything about which method is acceptable/preferred or if one
method yields significant performance benefit.  
>
>Since, according to the docs a Context is not guaranteed to be synchronized against concurrent
access by multiple threads, I assume that the first code segment above should be synchronized,
especially if it is in a static method.
>
>Thanks in advance,
>
>Gord 
>
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>  
>


-- 
=======================================
David Smith
Network Operations Supervisor
Department of Entomology
College of Agriculture & Life Sciences
Cornell University
2132 Comstock Hall
Ithaca, NY  14853
Phone: 607.255.9571
Fax: 607.255.0939


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