Understanding DB2®: Learning Visually with Examples

15.7. 32-Bit Memory Model Considerations

If you install DB2 on a 32-bit operating system, there are limitations to the maximum size of a shared memory segment that a process can allocate. Since each database has all of its shared memory allocated in the same segment, there is a limit on the total amount of shared memory that can be allocated per database.

In 32-bit AIX, there are a maximum of sixteen 256MB shared memory segments that can be addressed by a process. Of these sixteen segments, only seven can be used by DB2 for shared memory. By default, DB2 reserves one of these seven segments for optimizing memory-mapped I/O. If you have multiple logical partitions on the same server, DB2 also uses one of these seven segments for inter-partition ...