Don't forget about the thread dumps when you get the failures.
-- Dirk
Noel J. Bergman wrote:
Dirk verbeeck wrote:
Chris Means wrote:
The update for DBCP didn't fix the problem.
Bother ... worked all that time, and now failing again?
I have restarted it, and turned on DEBUG for: spoolmanager, pop3server, smtpserver, and mailstore.
That might not help, but we'll see. We'd want some detailed accounting from the connection pool when it is exhausted, so that we could see how is holding the connections.
are the blocking threads (threaddumps?) If we suspect a leak then ds.getNumActive() & ds.getNumIdle() should be printed (exception logging in JdbcDataSource.getConnection). If the numbers are correct (active=max and idle=0) then the DBCP abandoned connection tracing should be enabled to trace where the connection are allocated.
FWIW, the James code that uses this is:
http://cvs.apache.org/viewcvs.cgi/james-server/src/java/org/apache/james/uti l/dbcp/JdbcDataSource.java?annotate=1.1.2.3&only_with_tag=branch_2_1_fcs
Any suggestions on instrumentation? A patch would be welcomed. At the moment, I'm rather rushed for time, and don't have time to examine the issue in more detail immediately. We have our own adapter for the BasicDataSource, so adding the instrumentation should be fairly straight foward.
--- Noel
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package org.apache.james.util.dbcp; import java.io.PrintWriter; import java.sql.Connection; import java.sql.SQLException; import org.apache.avalon.excalibur.datasource.DataSourceComponent; import org.apache.avalon.framework.activity.Disposable; import org.apache.avalon.framework.configuration.Configurable; import org.apache.avalon.framework.configuration.Configuration; import org.apache.avalon.framework.configuration.ConfigurationException; import org.apache.avalon.framework.logger.AbstractLogEnabled; import org.apache.commons.dbcp.BasicDataSource; /** * <p> * This is a reliable DataSource implementation, based on the pooling logic provided by <a * href="http://jakarta.apache.org/commons/dbcp/";>DBCP</a> and the configuration found in * Avalon's excalibur code. * </p> * * <p> * This uses the normal <code>java.sql.Connection</code> object and * <code>java.sql.DriverManager</code>. The Configuration is like this: * <pre> * <jdbc> * <pool-controller min="<i>5</i>" max="<i>10</i>" connection-class="<i>my.overrided.ConnectionClass</i>"> * <keep-alive>select 1</keep-alive> * </pool-controller> * <driver><i>com.database.jdbc.JdbcDriver</i></driver> * <dburl><i>jdbc:driver://host/mydb</i></dburl> * <user><i>username</i></user> * <password><i>password</i></password> * </jdbc> * </pre> * </p> * <p> * These configuration settings are available: * <ul> * <li><b>driver</b> - The class name of the JDBC driver</li> * <li><b>dburl</b> - The JDBC URL for this connection</li> * <li><b>user</b> - The username to use for this connection</li> * <li><b>password</b> - The password to use for this connection</li> * <li><b>keep-alive</b> - The SQL query that will be used to validate connections from this pool before returning them to the caller. If specified, this query <strong>MUST</strong> be an SQL SELECT statement that returns at least one row.</li> * <li><b>max</b> - The maximum number of active connections allowed in the pool. 0 means no limit. (default 2)</li> * <li><b>max_idle</b> - The maximum number of idle connections. 0 means no limit. (default 0)</li> * </ul> * * @version CVS $Revision: 1.1.2.3 $ */ public class JdbcDataSource extends AbstractLogEnabled implements Configurable, Disposable, DataSourceComponent { BasicDataSource source = null; /** * @see org.apache.avalon.framework.configuration.Configurable#configure(Configuration) */ public void configure(final Configuration configuration) throws ConfigurationException { //Configure the DBCP try { String driver = configuration.getChild("driver").getValue(null); Class.forName(driver); String dburl = configuration.getChild("dburl").getValue(null); String user = configuration.getChild("user").getValue(null); String password = configuration.getChild("password").getValue(null); source = new BasicDataSource(); // Turn on validation, so // that the pool can recover from a server outage. source.setTestOnBorrow(true); source.setTestOnReturn(true); source.setDriverClassName(driver); source.setUrl(dburl); source.setUsername(user); source.setPassword(password); source.setMaxActive(configuration.getChild("max").getValueAsInteger(2)); source.setMaxIdle(configuration.getChild("max_idle").getValueAsInteger(0)); source.setValidationQuery(configuration.getChild("keep-alive").getValue(null)); //Unsupported //source.setLoginTimeout(configuration.getChild("login_timeout").getValueAsInteger(0)); //This is necessary, otherwise a connection could hang forever source.setMaxWait(configuration.getChild("max_wait").getValueAsInteger(5000)); source.setRemoveAbandoned(configuration.getChild("removeAbandoned").getValueAsBoolean(source.getRemoveAbandoned())); source.setRemoveAbandonedTimeout(configuration.getChild("removeAbandonedTimeout").getValueAsInteger(source.getRemoveAbandonedTimeout())); source.setLogAbandoned(configuration.getChild("logAbandoned").getValueAsBoolean(source.getLogAbandoned())); // DBCP uses a PrintWriter approach to logging. This // Writer class will bridge between DBCP and Avalon // Logging. Unfortunately, DBCP 1.0 is clueless about the // concept of a log level. final java.io.Writer writer = new java.io.CharArrayWriter() { public void flush() { // flush the stream to the log if (JdbcDataSource.this.getLogger().isErrorEnabled()) { JdbcDataSource.this.getLogger().error(toString()); } reset(); // reset the contents for the next message } }; source.setLogWriter(new PrintWriter(writer, true)); // Extra debug if (getLogger().isDebugEnabled()) { getLogger().debug("MaxWait: " + source.getMaxWait()); getLogger().debug("MaxIdle: " + source.getMaxIdle()); getLogger().debug("MaxActive: " + source.getMaxActive()); getLogger().debug("RemoveAbandoned: " + source.getRemoveAbandoned()); getLogger().debug("RemoveAbandonedTimeout: " + source.getRemoveAbandonedTimeout()); getLogger().debug("LogAbandoned: " + source.getLogAbandoned()); getLogger().debug("TestOnBorrow:" + source.getTestOnBorrow()); getLogger().debug("TestOnReturn:" + source.getTestOnReturn()); getLogger().debug("TestWhileIdle:" + source.getTestWhileIdle()); getLogger().debug("NumTestsPerEvictionRun: " + source.getNumTestsPerEvictionRun()); getLogger().debug("MinEvictableIdleTimeMillis: " + source.getMinEvictableIdleTimeMillis()); getLogger().debug("TimeBetweenEvictionRunsMillis: " + source.getTimeBetweenEvictionRunsMillis()); } //Get a connection and close it, just to test that we connected. source.getConnection().close(); } catch (Exception e) { getLogger().error("Error configurable datasource", e); throw new ConfigurationException("Error configurable datasource", e); } } /** * @see org.apache.avalon.framework.configuration.Configurable#dispose() */ public void dispose() { //Close all database connections try { source.close(); } catch (SQLException sqle) { getLogger().error("Error disposing datasource", sqle); } } public Connection getConnection() throws SQLException { if (getLogger().isDebugEnabled()) { getLogger().debug("getConnection()" + " NumActive: " + source.getNumActive() + " NumIdle: " + source.getNumIdle()); } try { return source.getConnection(); } catch (SQLException e) { getLogger().error("Error during getConnection()", e); getLogger().error("Pool stats" + " NumActive: " + source.getNumActive() + " MaxActive: " + source.getMaxActive() + " NumIdle: " + source.getNumIdle() + " MaxIdle: " + source.getMaxIdle()); throw e; } } }
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