Re: PostgreSQL/Tomcat JNDI Datasource Questions

Warren,

A JSP ends up being a servlet at some point. So I'd say that there
should still be a way to implement destroy inside a jsp page. ( I don't
believe in JSP, and this is just another reason )

Just thinking out loud you should be able to put a servlet into your
webapp that will just close the pool. All it would do is start on load,
and run destroy

Dave

Warren Killian wrote:

> Hi Dave,
>
> Good advice. But I'm afraid not using Servlets. My application is
> written entirely with JSP's in which I'm using the JSTL actions to
> perform all of the database operations. I've scanned all the
> information I can find on the "sql" JSTL and haven't found any action
> which would let me specifically close database connections. Have I
> missed something in my research? Thanks for the feedback.
>
> Warren Killian
> warrenk19(at)comcast(dot)net
>
> Dave Cramer wrote:
>
>> Warren,
>>
>> You need to implement destroy in your servlet and close the
>> connections when the servlet is destroyed.
>>
>> Dave
>>
>> Warren Killian wrote:
>>
>>> Hello group,
>>>
>>> I have several questions concerning configuring and using a JNDI
>>> DataSource
>>> with PostgreSQL and Apache Tomcat. Currently I have
>>> successfully configured a "basic" DataSource. Currently, my
>>> configuration
>>> which resides in a context.xml file is as follows:
>>>
>>> <Context className="org.apache.catalina.core.StandardContext"
>>> backgroundProcessorDelay="-1"
>>> cachingAllowed="true"
>>>
>>> charsetMapperClass="org.apache.catalina.util.CharsetMapper"
>>>
>>> configFile="/usr/local/jwsdp-1.3/conf/Catalina/localhost/test.xml"
>>> cookies="true"
>>> crossContext="false"
>>> debug="0"
>>> displayName="test"
>>> docBase="/usr/local/jwsdp-1.3/webapps/test"
>>> domain="Catalina"
>>> engineName="Catalina"
>>> j2EEApplication="none"
>>> j2EEServer="none"
>>> lazy="true"
>>> managerChecksFrequency="6"
>>> path="/test"
>>> privileged="false"
>>> reloadable="true"
>>> startupTime="8"
>>> swallowOutput="false"
>>> tldScanTime="0"
>>> useNaming="true"
>>>
>>> wrapperClass="org.apache.catalina.core.StandardWrapper">
>>>
>>> <Resource name="jdbc/test" scope="Shareable"
>>> type="javax.sql.DataSource"/>
>>> <ResourceParams name="jdbc/test">
>>> <parameter>
>>> <name>factory</name>
>>>
>>> <value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
>>> </parameter>
>>> <parameter>
>>> <name>driverClassName</name>
>>> <value>org.postgresql.Driver</value>
>>> </parameter>
>>> <parameter>
>>> <name>url</name>
>>> <value>jdbc:postgresql://myIP/test</value>
>>> </parameter>
>>> <parameter>
>>> <name>username</name>
>>> <value>Whoopie</value>
>>> </parameter>
>>> <parameter>
>>> <name>password</name>
>>> <value>Doopie</value>
>>> </parameter>
>>> <parameter>
>>> <name>removeAbandoned</name>
>>> <value>true</value>
>>> </parameter>
>>> <parameter>
>>> <name>removeAbandonedTimeout</name>
>>> <value>20</value>
>>> </parameter>
>>> <parameter>
>>> <name>maxWait</name>
>>> <value>5000</value>
>>> </parameter>
>>> <parameter>
>>> <name>maxActive</name>
>>> <value>5</value>
>>> </parameter>
>>> <parameter>
>>> <name>maxIdle</name>
>>> <value>2</value>
>>> </parameter>
>>> <parameter>
>>> <name>validationQuery</name>
>>> <value>SELECT * FROM test</value>
>>> </parameter>
>>> </ResourceParams>
>>> </Context>
>>>
>>> Using the above configuration, my JSP pages can connect to
>>> PostgreSQL and
>>> perform all required database operations.
>>>
>>> But all is not right! I have the following issues:
>>>
>>> 1.) Connections are NEVER closed
>>> Say I hit my JSP page which perform a query and display the results.
>>> Using netstat I can see that one connection to PostgreSQL has been
>>> established. But then, if I uninstall and reinstall my web app and
>>> hit my
>>> JSP page again, then the output of "netstat -p -t" shows that a second
>>> connection to PostgreSQL is established. The first connection never
>>> goes away! If I continue to
>>> uninstall/reinstall/hit JSP page, the connections continue to acrue and
>>> never go away. The number of connections can even exceed the value of
>>> "maxActive" defined in my context.xml file. What am I doing wrong?
>>>
>>> 2.) Idle connections aren't closed
>>> As mentioned above, the connections which are opened by my web app are
>>> kept around forever and never closed. In my context.xml file above,
>>> I've
>>> defined the "removeAbandoned" parameter to true and have set the
>>> "removeAbandonedTimeout" parameter to 20 seconds. But the
>>> connections are
>>> never closed. Every time I run "netstat -p -t", the connections are
>>> still there. :(
>>>
>>> 3.) Is my configuration correct for performing Pooling?
>>> I "can" get "a" database connection using this configuration. But
>>> is this
>>> adequate to perform connection pooling? How can I tell if/when
>>> connection
>>> pooling is actually being performed correctly?
>>> Any help would be greatly appreciated.
>>>
>>
>

--
Dave Cramer
http://www.postgresintl.com
519 939 0336
ICQ#14675561