Partitioning rules set using dsi_partitioning_rule allow the parallel DSI feature to make decisions about transaction groups and parallel execution based on transactions having common names, users, overlapping begin/commit times, or a combination of these.
Partitioning rules allow the parallel DSI feature to more closely mimic processing order at the primary, and are intended to be used in reducing contention at the replicate.
Each of the parallel DSI parameters provides a method for fine-tuning the feature based on conditions at your installation. dsi_num_threads controls the number of DSI threads available for a connection. dsi_serialization_method controls the amount of parallelism for the connection, but must balance increased parallelism with the potential for contentions at the replicate. dsi_partitioning_rule provides a method for reducing contentions without reducing the overall capabilities of the parallel DSI feature.