Bug 123840 Incorrect use of static fields in NEvaluator and FilterPassController
Data Engine classes org.eclipse.birt.data.engine.script.NEvaluator and FilterPassController (used for top-n and bottom-n filter process) use static class fields to store proessing data. This is not multi-thread safe. If there are concurrent requests running in the same JVM (even if they use different instances of DataEngine), data corruption will occur since multiple requests may get/set the static fields at the same time. These classes should keep all per-request data in instance fields. Each report query need to have its own instance.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/script/NEvaluator.java
}
	}
	
	/**
	 * Do the second pass
	 * @param N
	 * @return
	 */
	private boolean doSecondPass( )
	{
		secondPassRowNumberCounter++;
		if ( qualifiedRowCounter < N )
		{
			for ( int i = 0; i < N; i++ )
			{
				if ( rowIdList[i] == secondPassRowNumberCounter )
				{
					qualifiedRowCounter++;
					reset( );
					return true;
				}
			}
			return false;
		}
		else
		{
			reset( );
			return false;
		}
	}