use_rssd

Determines whether Replication Agent uses replication definitions.

Default

true

Values

true – enables using replication definitions.

false – disables using replication definitions.

Comments

  • If the value of the use_rssd parameter is true, the Replication Agent instance connects to the Replication Server System Database (RSSD) to retrieve replication definitions for the primary database automatically whenever it goes from Replication Down state to Replicating state (for example, when the resume command is invoked).

    • Each time it retrieves replication definitions, Replication Agent stores the information in a cache. Replication Agent uses replication definitions stored in its cache when it generates Log Transfer Language (LTL) commands.

    • If the Log Transfer Interface (LTI) component encounters an operation on a database object for which it does not have a cached replication definition, Replication Agent reconnects to the RSSD to update its replication definition cache.

    • If a replication definition still cannot be found for the operation, the Replication Agent instance suspends all of its replication operations and goes to Replication Down state.

  • Replication Agent can use information in table and function replication definitions (that is, replication definitions for individual primary database objects) stored in the RSSD to generate more efficient LTL, and thus improve throughput in the LTI component and Replication Server.

    Accessing replication definitions in the RSSD enables the LTI component to improve performance by:

    • Omitting column names in LTL. When columns are sent in the order specified in the replication definition, column images can be sent without column names (headings), which reduces LTL overhead.

    • Omitting unneeded columns in LTL. When columns are sent as specified in the replication definition, images for unchanged columns need not be sent, which reduces LTL overhead.

    • Sending data for each column in the datatype specified by the replication definition. This allows data to be handled more efficiently all the way through the replication system.

    • Sending database object names in the same character case as defined in the replication definition.

  • If the value of the use_rssd parameter is false, none of the previously described performance improvements are possible. In that case, Replication Agent sends all data as a char datatype in the LTL.