[jboss-dev-forums] [Design of JCA on JBoss] - Re: JDBC/XA changes to better support MSSQL Server

[adrian@jboss.org]

Original discussion:

Problem: Need to invoke Statement.cancel() otherwise XAResource.rollback()
blocks.

anonymous wrote : 
  | So basically we need to add something to the jdbc resource adapter
  | such that when XAResource.prepare(), commit(onePhase) or rollback()
  | or for local tx Connection.commit()/rollback()
  | is invoked, we check whether there are any currently "open"
  | statements and issue a cancel().
  | 
  | We already keep track of unclosed statements in WrappedConnection
  | so this should be a fairly trivial change?
  | 
  | I guess also, that if a close() is going to block,
  | we should also do the same cancel() when we close statements
  | (or return the statement to the prepared statement cache)
  | in response to a close() on the connection wrapper.
  | 

and

anonymous wrote : 
  | I'm saying the JCA layer should do it
  | (in cases where the jdbc adapter doesn't do it itself).
  | 
  | The stack would look something like this?
  | 
  | org.jboss.resource.adapter.jdbc.WrappedConnection.cancelStatements();
  | org.jboss.resource.adapter.jdbc.BaseWrapperManagedConnection.checkComplete();
  | org.jboss.resource.adapter.jdbc.xa.XAManagedConnection.rollback();
  | tm.handleTimeout();
  | 
  | Before doing the real delegation:
  | 
  | com.acme.xadatasource.XAResourceImpl.rollback();
  | org.jboss.resource.adapter.jdbc.xa.XAManagedConnection.rollback();
  | tm.handleTimeout();
  | 
  | The same feature would work for local datasources as well
  | since we give you a LocalXAResource that invokes the
  | ManagedConnection's local commit/rollback, i.e.
  | 
  | org.jboss.resource.adapter.jdbc.WrappedConnection.cancelStatements();
  | org.jboss.resource.adapter.jdbc.BaseWrapperManagedConnection.checkComplete();
  | org.jboss.resource.adapter.jdbc.local.LocalManagedConnection.rollback();
  | org.jboss.resource.cm.TxConnectionManager$LocalXAResource.rollback();
  | tm.handleTimeout();
  | 

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