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  1. Commons DBCP
  2. DBCP-568

ManagedConnection must clear its cached state after transaction completes

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: Minor
    • Resolution: Fixed
    • Affects Version/s: 2.0
    • Fix Version/s: 2.9.0
    • Labels:
      None
    • Flags:
      Patch

      Description

      There's a spurious log (see log in comment) about failure to rollback a connection in the following context:

      • use of a managed connection
      • cacheState=true (the default)
      • rollback initiated by the transaction manager
      • rollbackOnReturn=true (the default)
      • JDBC driver that refuses to rollback when autoCommit=true (like the PostgreSQL driver)

      The sequence of events leading to the error is:

      • transaction started
      • application acquires managed connection from pool (wrapping the low-level PgConnection)
        • connection enlisted in transaction
        • LocalXAConnectionFactory.LocalXAResource.start sets low-level connection autoCommit=false
      • application does some work
      • application check connection's autoCommit state for various reasons
        • calls DelegatingConnection.getAutoCommit which caches the state (false)
      • application does more work and signals the transaction manager to rollback
      • transaction manager rolls back
        • all enlisted resources roll back
          • LocalXAConnectionFactory.LocalXAResource.rollback rolls back and sets low-level autoCommit=true
      • managed connection is closed
        • PoolableConnection.close calls PoolableConnectionFactory.passivateObject
        • passivation does rollback-on-return which checks for connection autoCommit before doing rollback
          • the autoCommit status returned is the one cached in DelegatingConnection so still false
          • rollback is called on low-level connection, which throws because it's still in state autoCommit=true

      There are several workarounds:

      • use cacheState=false in the datasource config
      • use rollbackOnReturn=false in the datasource config

      But the correct fix is to make the DelegatingConnection aware that during rollback something was changed at low-level and its cache is invalid. This can be done by making ManagedConnection.transactionComplete (which is called in afterCompletion) clear the cached state.

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              • Assignee:
                Unassigned
                Reporter:
                fguillaume Florent Guillaume
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