Enable dsi_cmd_prefetch to improve Data Server Interface (DSI) efficiency by reducing data replication latency which decreases the length of time that Replication Server waits for results from the replicate data server through the ct_results routine, and subsequently reduces the length of time the data server waits for Replication Server..
Enhancing DSI efficiency reduces latency by:
Allowing Replication Server to prepare the next batch of commands for the replicate data server before Replication Server processes results of the current batch from the replicate data server.
Improving concurrency between the DSI Executor (DSI/E) and DSI Scheduler (DSI/S) threads.
To allow DSI to pre-build the next batch of commands while waiting for the response from data server, and therefore improve DSI efficiency, set dsi_cmd_prefetch to ‘on’ with alter connection or create connection.
If you also tune your data server to enhance performance, you may gain an additional performance increase when you enable dsi_cmd_prefetch.
For example, to enable dsi_cmd_prefetch for the connection to the pubs2 database in the SYDNEY_DS data server:
alter connection to SYDNEY_DS.pubs2 set dsi_cmd_prefetch to ‘on’
Default: on.
dsi_cmd_prefetch is a dynamic parameter.
When you set dsi_compile_enable to ‘on’,
Replication Server ignores what you set for dsi_cmd_prefetch.
