Database Server System Requirements
From the point of view of the operating system, a database server requires the system resources described in the following sections.
The amount of physical memory used by the database server process is determined by parameters in the local database definition, see The Local Database, whose initial default values are determined by looking at the amount of installed memory.
VMS: For a database server running on an OpenVMS node the amount of physical memory used by the database server process will vary between the OpenVMS process parameters WSQUOTA and WSEXTENT.
The WSQUOTA parameter is calculated by MIMCONTROL and is set large enough to include the bufferpool, communication buffers, code, and stack data.
The WSEXTENT parameter is taken from the parameter with the same name in the MULTIDEFS file, see The MULTIDEFS Parameter File. The default value for WSEXTENT is the SYSGEN parameter WSMAX (the maximum amount of physical memory a single process may have).
The amount of virtual memory that the database server process can use is limited by the operating system.
VMS: The MIMCONTROL command sets the paging file quota of the database server so that it is large enough to contain all memory areas, including the bufferpool and an SQLPOOL that has grown to MaxSQLPool kilobytes.
VMS: The database server creates a global section for its communication buffers. This global section resides on the page file. The amount of memory a global section may take from a page file is generally controlled by an operating system parameter. If this limit set by the operating system is exceeded, the MIMCONTROL/START command will fail with the message:
Upright Database Technology AB
Voice: +46 18 780 92 00
Fax: +46 18 780 92 40