Optimized fetch

When optimized fetch is enabled, rows ahead of the current row are asynchronously extracted before the client application requests them. This data is then returned to the client application in blocks that may be as large as 32 KB. Enabling optimized fetch helps to minimize network traffic and speeds subsequent fetches as the requested data is likely already in a returned block.

Optimized fetch is enabled either by including the RO=YES connection property in a connection string (a connection string may be used with a DSN) or by appending the FOR FETCH ONLY clause to a SELECT statement.

When optimized fetch is enabled, cursor that is based deletes (DELETE WHERE CURSOR OF) cannot be used.