The behavior of the data in your RSB cache, when an automatic transition occurs, is controlled by the transition property, apply-streaming-data. The apply-streaming-data property may be set to either 1 or 0. The setting indicates the following:

  • apply-streaming-data=1 — When the transition timeout expires, the replication agent waits for all entries in the RSB cache to be applied to the target database before continuing with auto-transition.
  • apply-streaming-data=0 — When the transition timeout expires, the replication agent discards all entries in the RSB cache and continues with auto-transition.

The apply-streaming-data property defaults to 0 unless explicity set to 1 in the properties file. Setting the apply-streaming-data property to values other than 1 is the equivalent of setting it to 0.

For all possible configurations of replication (one target, two target, replication set)1, when apply-streaming-data=1, all the data in the RSB cache is written to the target database before transition.

Auto-transition for one-target or two-targets (no replication set)

In this configuration, the agents handle data in the RSB cache with the following steps:

  1. The agent reaches time to transition.
  2. Check the apply-streaming-data setting.
    • If 1, check if the RSB cache is empty.
      • Yes — initiate auto-transition, writing this message to the log file:
        Agent's RSB cache is empty.  Ready for auto-transition.   (19317 )
      • No — reset the time to transition and return to Step 1, after writing these messages to the log file:
        %l<num> blocks exist in RSB cache.  The Agent will transition after all blocks in the RSB cache have been applied to the database. (19300)
The transition time has been reset to allow for RSB cache to empty before auto transition. (19301)
    • If 0, check if the RSB cache is empty.
      • Yes — initiate auto-transition, writing this message to the log file:
        Agent's RSB cache is empty.  Ready for auto-transition.   (19317 )
      • No — initiate auto-transition, writing this message to the log file:
        Automatic transition is starting, there are up to %l<num> blocks in the RSB cache that will not be processed. (19299)

Auto-transition for a two target replication set

In this configuration, the agents handle data in the RSB cache with the following steps. If at any time during the processing of the RSB cache prior to transition, the agents lose inter-agent communication, the replication set is broken and the agents transition as single agents, using the prior process.

  1. The local agent reaches time to transition. (Each agent acts as a local agent, communicating with the other "remote" agent.)
  2. Check if the RSB cache has been processed.
    • Yes — Proceed to Step 3.
    • No — Process the RSB cache.

      Check the apply-streaming-data setting:

      • 1 — Process RSB cache data before transition.

        Check if the RSB cache is empty.

        • Yes — Ping the remote agent that the RSB cache is empty, and the local agent is ready for transition. Write the following message to the log file:
          Agent's RSB cache is empty.  Ready to transition with replication-set. (19311)
        • No — Ping the remote agent that the RSB cache is not empty, the local agent is processing the cache, and is not ready for transition. Write the following messages to the log file and repeat this step:
          %l<num> blocks exist in RSB cache.  The Agent will transition after all blocks in the RSB cache have been applied to the database. (19300)
The transition time has been reset to allow for RSB cache to empty before auto transition. (19301)
      • 0 — Do not process RSB cache data before transition.

        Check if the RSB cache is empty.

        • Yes — Ping the remote agent that RSB cache is empty and the local agent is ready for transition. Write the following message to the log file:
          Agent's RSB cache is empty.  Ready to transition with replication-set.   (19311)
        • No — Discard the remaining blocks in the RSB cache. Ping the remote agent that cache is empty and the local agent is ready for transition. Write the following message to the log file:
          Agent is ready to transition with replication-set.  There are up to %l<num> blocks in the RSB cache that will not be processed.(19312)
    Note: When the remote agent receives a ping from the local agent, it sets its time to transition to the current time to begin handling of its own RSB cache. The remote agent writes the following message to its log file: 
    Remote agent has signaled that it processed its RSB data and is ready for auto-transition. (19316)
  3. Check communications status with the remote agent.

    Has the remote agent sent a message indicating that it has completed processing its RSB cache and is ready to transition?

    • No — Ping the remote agent to confirm it is still connected. Reset the time to transition, and return to Step 1 after writing the following message to the log file:
      Waiting for remote agent to process its RSB data and signal that it is ready to auto-transition.(19314)
    • Yes — Proceed to Step 4.
  4. Confirm that both agents are ready to proceed with auto-transition.

    Both agents write the following message to their log file:

    Both agents in the replication-set have processed their RSB data and are ready for auto-transition.(19315)

    The priority agent initiates transition, and the other agent waits to be notified by the priority agent that transition processing is proceeding.

1 Progress Software recommends configuring two-target replication environments as a replication set to avoid rebasing after transition.