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This is documentation for Caché & Ensemble. See the InterSystems IRIS version of this content.

For information on migrating to InterSystems IRIS, see Why Migrate to InterSystems IRIS?


Size of the generic memory heap.


[config]  gmheap=n


Number of kilobytes allocated for the generic memory heap for Caché. This is the allocation from which the Lock table, the NLS tables, and the PID table are also allocated. For Asian locales, add one extra megabyte (1024 KB) to the total gmheap value.


To ensure optimal performance during a journal restore, InterSystems recommends increasing the generic memory heap size; see Restore Journal Files in the “Journaling” chapter of the Cache Data Integrity Guide for more information.

The generic memory heap (gmheap) is sometimes known as the shared memory heap (SMH).




Range of Values

16 MB to one terabyte. The default is 37568 KB (37 MB). On IBM AIX, the default is 53952 KB (54 MB).

Management Portal

On the page System Administration > Configuration > Additional Settings > Advanced Memory, in the gmheap row, select Edit. Enter a number of kilobytes.