The DataServer keeps a cache of prepared SQL statements that it reuses with new parameters. This mechanism improves the DataServer performance. You can use the PRGRS_PREPCACHE option to manage this cache in two ways:
The MS SQL Server drivers are capable of re-using prepared statements and should do so whenever possible. However, using -Dsrv PRGRS_PREPCACHE,0 instructs the DataServer to re-prepare each SQL statement.
Use the PRGRS_PREPCACHE option to control the size of the cache. The default cache size is 20 statements. You can increase the size for large applications that reuse many queries. The maximum size depends on the amount of resources you have available.