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  1. Commons DBCP
  2. DBCP-244

Connection socket hangs sporadically in DBCP 1.2.2 but not 1.2.1

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Cannot Reproduce
    • Affects Version/s: 1.2.2
    • Fix Version/s: 1.3
    • Labels:
      None
    • 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.

      Description

      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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              • Assignee:
                Unassigned
                Reporter:
                os111 ori
              • Votes:
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                • Created:
                  Updated:
                  Resolved: