The PrefetchRows connection parameter sets the maximum number of rows to prefetch when querying the database.
Increasing the number of rows prefetched from the database server by the client can improve performance on cursors that do only fetch relative 0 or 1, with either single row or wide fetches. Wide fetches include embedded SQL array fetches and ODBC block fetches.
Improvements occur particularly under the following conditions:
The application fetches many rows (several hundred or more) with very few absolute fetches.
The application fetches rows at a high rate, and the client and server are on the same machine or connected by a fast network.
Client/server communication is over a slow network, such as a dial-up link or wide area network.
The number of rows prefetched is limited both by the PrefetchRows connection parameter and the PrefetchBuffer parameter, which limits the memory available for storing prefetched rows.
The maximum number of rows that can be prefetched is 1000.