Can you add the stuff from my email?
-----Original Message-----
From: Kaleb Pederson [mailto:[EMAIL PROTECTED]
Sent: October 4, 2004 12:40 PM
To: Tomcat Users List
Subject: Re: Tomcat becoming almost completely non-responsive
My datasource definition is pretty basic and is as follows:
<!-- the db object for the mapping database -->
<Resource name="jdbc/MappingDB" auth="Container"
type="javax.sql.DataSource" />
<ResourceParams name="jdbc/MappingDB">
<parameter>
<name>removeAbandoned</name>
<value>true</value>
</parameter>
<parameter>
<name>removeAbandonedTimeout</name>
<value>60</value>
</parameter>
<parameter>
<name>logAbandoned</name>
<value>true</value>
</parameter>
<parameter>
<name>factory</name>
<value>org.apache.commons.dbcp.BasicDataSourceFactory</value>
</parameter>
<parameter>
<name>username</name>
<value>redirect_user</value>
</parameter>
<parameter>
<name>password</name>
<value>redirect_pass</value>
</parameter>
<parameter>
<name>driverClassName</name>
<value>com.mysql.jdbc.jdbc2.optional.MysqlDataSource</value>
</parameter>
<parameter>
<name>url</name>
<value>jdbc:mysql://myhost/redirects</value>
</parameter>
<parameter>
<name>maxActive</name>
<value>50</value>
</parameter>
<parameter>
<name>maxIdle</name>
<value>4</value>
</parameter>
<parameter>
<name>validationQuery</name>
<value>show tables</value>
</parameter>
</ResourceParams>
Thanks for the help.
--Kaleb
On Monday 04 October 2004 8:54 am, Phillip Qin wrote:
> Post your datasource resource definition. You may miss something like
>
> <parameter>
> <name>testOnBorrow</name>
> <value>true</value>
> </parameter>
> <parameter>
> <name>testOnReturn</name>
> <value>true</value>
> </parameter>
> <parameter>
> <name>minEvictableIdleTimeMillis</name>
> <value>-1</value>
> </parameter>
> <parameter>
> <name>timeBetweenEvictionRunsMillis</name>
> <value>300000</value>
> </parameter>
> <parameter>
> <name>numTestsPerEvictionRun</name>
> <value>1</value>
> </parameter>
> <parameter>
> <name>testWhileIdle</name>
> <value>true</value>
> </parameter>
>
>
> -----Original Message-----
> From: Kaleb Pederson [mailto:[EMAIL PROTECTED]
> Sent: October 4, 2004 11:19 AM
> To: Tomcat Users List
> Subject: Re: Tomcat becoming almost completely non-responsive
>
>
> John,
>
> Thanks for the feedback. My code is actually quite simple and I have
> everything factored out to single function that handles the DB code.
> I'll paste it below for you, and others to look at. *Please let me
> know* if there is an exit path that I somehow missed.
>
> I already have tomcat setup to log abandoned connections. At your
> instigation, I grep'd the logs and found a few instances of it in the
> logs which I was unaware of. Each one of them corresponds to a time
> we had high load on the server, so I, hopefully not niavely ;), am
> guesssing that the abandoned timeout was shorter (currently 60
> seconds) than the time it took the server to respond to the request
> (up to 5 minutes). I guess I should up
>
> the abandoned timeout as that could flame the problem.
>
> If I'm interpreting the thread dump and mysqladmin processlist
> information correctly, what I'm seeing is that MySQL considers the DB
> connection to be sleeping, and that 48 of my active db threads were in
> object.wait() after a call to AbandonedObjectPool.borrowObject()
> which seems to get called in every case after a call to
> DataSource.getConnection():
>
> // note that I removed the org.apache.commons prefix
> 48 like "TP-Processor312" daemon prio=1 tid=0x70331680 nid=0x5e87
>waiting for monitor entry [6df79000..6df7a87c] at
>
dbcp.PoolableConnectionFactory.validateObject(PoolableConnectionFactory.jav
>a
>
> :316)
>
> - waiting to lock <0x7b071438> (a dbcp.PoolableConnectionFactory)
> at
pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:833)
> at dbcp.AbandonedObjectPool.borrowObject(AbandonedObjectPool.java:119)
> at dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:140)
> at dbcp.BasicDataSource.getConnection(BasicDataSource.java:518)
> // the function in my filter that checks the DB.
> at RequestFilterServlet.getUrlMapping(RequestFilterServlet.java:187)
> ...
>
> Here's the code that handles the db:
>
> protected RedirectInfo getUrlMapping(String requestURI) {
>
> RedirectInfo retval = null;
> Connection conn = null;
> Statement statement = null;
> ResultSet result = null;
>
> try {
> conn = ds.getConnection();
> statement = conn.createStatement();
> statement.setEscapeProcessing(true);
> result = statement.executeQuery(QUERY_UNIQUE_MATCH +
> quote(requestURI));
>
> if (!result.first()) {
> result = statement.executeQuery(QUERY_CHILD_MATCH_1 +
> quote(requestURI)
> +
> QUERY_CHILD_MATCH_2);
> }
>
> // get the information
> if (result.first()) {
> retval = new RedirectInfo();
> retval.setURL(result.getString(1));
> retval.setCode(result.getInt(2));
> debug(requestURI + " -> " + retval.getURL() + " [" +
> Integer.toString(retval.getCode()) + "]");
> } else {
> debug("No matching redirect URL found for " + requestURI);
> }
> } catch(SQLException e) {
> log("SQLException caught: " + e.getMessage(), e);
> } finally {
> try {
> // cleanup after myself
> if (statement != null) statement.close();
> if (conn != null) conn.close();
> } catch (SQLException e) {
> log("Error cleaning up connection/statement: " + e.getMessage(),e);
> }
> }
>
> return retval;
> }
>
> Thanks for all the help.
>
> --Kaleb
>
> On Sunday 03 October 2004 1:58 pm, [EMAIL PROTECTED] wrote:
> > The most likely reason for your connections not being re-used is
> > that your java code isn't explicitly closing connections, statements
> > and result sets after use. If visiting all your code is too onerous
> > a task, you could add the following parameters to your data-source
> > configuration:
> >
> > <parameter>
> > <name>removeAbandoned</name>
> > <value>true</value>
> > </parameter>
> > <parameter>
> > <name>removeAbandonedTimeout</name>
> > <value>60</value>
> > </parameter>
> >
> > The effect of the above is to mark any data-pool connection as
> > re-usable after 60 seconds of inactivity. You can add the following
> > to log abandonned connection activity:
> >
> > <parameter>
> > <name>logAbandoned</name>
> > <value>true</value>
> > </parameter>
> >
> > John Thompson
> >
> > |---------+---------------------------->
> > |
> > | | Kaleb Pederson |
> > | | <[EMAIL PROTECTED]|
> > | | wu.edu> |
> > | |
> > | | 02/10/2004 10:07 |
> > | | AM |
> > | | Please respond to|
> > | | "Tomcat Users |
> > | | List" |
> > |
> > |---------+---------------------------->
> >
> >---------------------------------------------------------------------
> >---
> >
> > >--------------------------------------|
> > >
> > | To: Tomcat Users List <[EMAIL PROTECTED]>
> > |
> > | | cc:
> > |
> > | Subject: Tomcat becoming almost completely non-responsive
> >
> >---------------------------------------------------------------------
> >---
> >
> > >--------------------------------------|
> >
> > Hello,
> >
> > I have an interesting problem. After a while, tomcat (5.0.27)
> > becomes almost completely non-responsive. If I telnet in to port
> > 8009 (I'm using apache and mod_jk2), I get no response, at least
> > not within the default timeout. If a browse to a page, I will
> > generally, after about 4-5 minutes, see a page returned.
> >
> > To narrow down the slowness, I generated a full thread dump, and
> > found the following information:
> >
> > [ see attachment for more info]
> > Total threads: 180
> > executeQuery: 2 // executing a db query
> > validateConnection: 0 // trying to validate their connection
> > validateObect: 48 // in
> > commons.dbcp.PoolableConnectionFactory.validateObject
> > socketAccept: 3 // accepting a socket
> > socketRead0: 10 // reading a socket
> > ReferenceQueue: 1
> > ThreadPool$MonitorRunnable: 2
> > borrowObject and Object.wait: 85 // trying to get an object from the
> > pool
> > Object.wait: 20 // threads just waiting around
> > Remaining: 9 // misc. threads
> >
> > My database connection is setup so that I have 50 allowed
> > connections, which matches my 48 in validateObject and 2 executing
> > queries. However, when I query the database status, I see 2 active
> > threads and the rest are 'sleeping', just waiting around, as they
> > would be if the connection pool hadn't released them yet.
> >
> > So, why would there be 48 connections that seemed locked and weren't
> > querying the DB? And then the other 85 that were seemingly waiting
> > on the 45? Any ideas what might be going on? The DB is ready? I
> > have log abandoned turned and an haven't seen a problem yet. If the
> > load drops sufficiently on the server, everything eventually returns
> > back to normal, otherwise it takes 5-10
> > minutes to get a response from the server.
> >
> > I have attached an abbreviated form of the thread dump which should
> > provide all the critical information and can provide as much other
> > information as is necessary.
> >
> > Thanks for the help. *All* suggestions welcome ;)
> >
> > --Kaleb
> >
> >
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