Enhancing Efficiency with Application Parameters

The following application parameters enable you to enhance the efficiency of your system:

Setting the MAXACCESSERS, MAXSERVERS, MAXINTERFACES, and MAXSERVICES Parameters

The MAXACCESSERS, MAXSERVERS, MAXINTERFACES, and MAXSERVICES parameters increase semaphore and shared memory costs, so you should carefully weigh these costs against the expected benefits before using these parameters, and choose the values that best satisfy the needs of your system. You should take into account any increased resources your system may require for a potential migration. You should also allow for variation in the number of clients accessing the system simultaneously. Defaults may be appropriate for a generous allocation of IPC resources; however, it is prudent to set these parameters to the lowest appropriate values for the application.

Setting the MAXGTT, MAXBUFTYPE, and MAXBUFSTYPE Parameters

To determine whether the default is adequate for your application, multiply the number of clients in the system times the percentage of time they are committing a transaction. If the product of this multiplication is close to 100, you should increase the value of the MAXGTT parameter. As a result of increasing MAXGTT:

To limit the number of buffer types and subtypes allowed in the application, set the MAXBUFTYPE and MAXBUFSTYPE parameters, respectively. The current default for MAXBUFTYPE is 16. If you plan to create eight or more user-defined buffer types, you should set MAXBUFTYPE to a higher value. Otherwise, you do not need to specify this parameter; the default value is used.

The current default for MAXBUFSTYPE is 32. You may want to set this parameter to a higher value if you intend to use many different VIEW subtypes.

Tuning with the SANITYSCAN, BLOCKTIME, BBLQUERY, and DBBLWAIT Parameters

If a system is running on slow processors (for example, due to heavy usage), you can increase the timing parameters: SANITYCAN, BLOCKTIME, and individual transaction timeouts.

If networking is slow, you can increase the value of the BLOCKTIME, BBLQUERY, and DBBLWAIT parameters.

Recommended Values for Tuning-related Parameters

In the following table are recommended values for the parameters available for tuning an application.