n is an integer in the range 128—2,147,483,647 (KB). The default value is 262,144.
bbsiz is the maximum memory allocation permitted for a process (in kilobytes). This amount of process private memory is used for symbol table allocation and various other memory requirements, including I/O devices. It is allocated in increasing extents as required by the application until the maximum is reached. When a process starts, its initial allocation is 128 kilobytes.
Once this memory is allocated to the process, it is generally not deallocated until the process exits. However, when a large amount of memory is used (for example greater than 32MB) and then freed, InterSystems IRIS® data platform attempts to release deallocated memory back to the operating system where possible.
Changing This Parameter
On the Memory and Startup page of the Management Portal (System Administration > Configuration > System Configuration > Memory and Startup), enter a number of kilobytes in the Maximum Per-Process Memory (KB) row.
Instead of using the Management Portal, you can change bbsiz in the Config.config class (as described in the class reference) or by editing the CPF in a text editor (as described in the Editing the Active CPF section of the “Introduction to the Configuration Parameter File” chapter in this book).