The DSI thread translates the transaction modifications into RPCs or the language as specified by the function strings in the function-string class assigned to the destination database.
Replication Server starts DSI threads to submit transactions to a replicate database to which it has a connection.
Collects small transactions into groups by commit order.
Maps functions to function strings according to the function-string class assigned to the database connection.
Executes the transactions in the replicate database.
Takes action on any errors returned by the data server; depending on the assigned error actions, also records any failed transactions in the exceptions log.
To improve performance in sending transactions from a Replication Server to a replicate database, you can configure a database connection so that transactions are applied using multiple DSI threads. See Replication Server Administration Guide Volume 2 > Performance Tuning > Use Parallel DSI threads for a description of this feature.
Replication Server version 15.2 introduces support for bulk copy-in to improve performance when replicating large batches of insert statements on the same table in Adaptive Server® Enterprise 12.0 and later. Replication Server implements bulk copy-in using the Open Client™ Open Server™ Bulk-Library. See Replication Server Administration Guide Volume 2 > Performance Tuning > DSI Bulk Copy-in.
The DSI thread may apply a mixture of transactions from all data sources supported by the Replication Server. The transactions are processed in the single outbound stable queue for the destination data server.