OLAP Setup and User's Guide

Setting Up Your Environment

When you set up your Windows NT environment for use with DB2 OLAP Server, use the following guidelines:

• Set the DB2NTNOCACHE environment variable to 1 (DB2NTNOCACHE=1).

  This prevents DB2 from using Windows NT file system caching for database files; DB2 buffer pools are used to cache relational database data instead. Because DB2 buffer pools are used for caching, this eliminates double buffering and removes contention for memory between DB2 buffer pools and the Windows NT file system, which would degrade performance.

• Ensure that the Windows NT registry entry HKEY_LOCAL_MACHINE\SYSTEM\CurentControlSet\Control\Session Manager\Memory Management\LargeSystemCache is set to 0.

  This entry is normally set to 0. However, during installation of the Windows NT server, the value can be set to 1 if the server is configured for serving data rather than for running applications. It is not recommended that you run DB2 OLAP Server on a Windows NT server that is configured for serving data, because, in this situation, Windows NT gives priority for memory usage to caching files at the expense of the working set of applications that is running on the server.

Make sure your operating system is at the latest service level and is generally well tuned.