Component Roles During Data Loads - Access Module

• For load jobs, the sender is a customer-supplied component responsible for the following:
  • Formatting a data message that is defined by the Teradata load utility. The data message type can either be a simple text message (Type TextMessage) or a stream of bytes (Type ByteMessage).
  • Placing a data message on a specified queue or at certain destination, called a topic.
  • Sending a control message (zero-length message) to indicate the end of the message stream.
• For load jobs, the receiver is the Teradata Access Module for JMS, which is responsible for the following:
  • Performing a JNDI lookup to retrieve JMS-administered objects from the naming space.
  • Establishing communication with the JMS provider.
  • Retrieving the data message from the queue or topic.
  • Copying the data message to a fallback file for checkpoint and restart operations.
  • Passing the data message to the Teradata load utility, which then processes and loads the data into a database.
  • Continuing to retrieve data messages from the queue or topic until a control message (zero-length message) is received, or until a timeout is received that signals the end of the message stream.