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https://issues.apache.org/jira/browse/DBCP-244?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12565034#action_12565034
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Phil Steitz commented on DBCP-244:
----------------------------------
One possibility is that this change in behavior is caused by the change to
address DBCP-102. In 1.2.1, PoolableConnectionFactory's activate method
*always* did
(*) conn.setAutoCommit(_defaultAutoCommit);
Could be stale / timed out MySQL connections throw (quickly) on this. Pool's
borrowObject would swallow this and try to get another connection, moving
along. The change to address DBCP-102 was to test the property in (*) before
resetting it, because for some drivers this caused a network hit. So in 1.2.2,
activate succeeds, the client gets back the stale connection and things don't
go south until the connection is used.
Try adding conn.setAutoCommit(true) immediately after getConnection and before
using the connection after wakeup. If this resolves the issue, then the
hypothesis above is correct.
> Connection socket hangs sporadically in DBCP 1.2.2 but not 1.2.1
> ----------------------------------------------------------------
>
> Key: DBCP-244
> URL: https://issues.apache.org/jira/browse/DBCP-244
> Project: Commons Dbcp
> Issue Type: Bug
> Affects Versions: 1.2.2
> Environment: Fedora Core 3, MySQL 4.1.22. with the latest driver
> (5.07). Exceptions only occur in the "job processing" JVM, which sits idle
> for long periods of time and occasionally wakes up to interact with the
> database.
> Reporter: ori
> Fix For: 1.3
>
>
> I think I've traced an exception to DBCP's code.
> Communication with the database is hanging sporadically in a production
> environment. If I don't set the socketTimeout property on the underlying
> connection, it will hang forever. With the socketTimeout property, I get the
> following exception:
> -------
> com.mysql.jdbc.CommunicationsException: Communications link failure due to
> underlying exception:
> ** BEGIN NESTED EXCEPTION **
> java.net.SocketTimeoutException
> MESSAGE: Read timed out
> STACKTRACE:
> java.net.SocketTimeoutException: Read timed out
> at java.net.SocketInputStream.socketRead0(Native Method)
> at java.net.SocketInputStream.read(SocketInputStream.java:129)
> at
> com.mysql.jdbc.util.ReadAheadInputStream.fill(ReadAheadInputStream.java:113)
> at
> com.mysql.jdbc.util.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:160)
> at
> com.mysql.jdbc.util.ReadAheadInputStream.read(ReadAheadInputStream.java:188)
> at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:1994)
> at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:2411)
> at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2916)
> at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1631)
> at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1723)
> at com.mysql.jdbc.Connection.execSQL(Connection.java:3250)
> at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1355)
> at com.mysql.jdbc.Statement.executeUpdate(Statement.java:1270)
> at
> org.apache.commons.dbcp.DelegatingStatement.executeUpdate(DelegatingStatement.java:228)
> ...
> -------
> It always happens in an infrequently used JVM (not an app server handling
> frequent connections). So it's likely the offending connection was asleep for
> a long time before the exception occurs.
> I've confirmed that this issue only occurs using 1.2.2 and not 1.2.1. I've
> been looking through the changelogs but can't find anything that would cause
> this behavior.
> Does somebody familiar with the codebase have any idea what change
> (1.2.1->1.2.2) could be causing this behavior?
> Thanks
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