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Object documentation Shared Memory (Informix)  Locate the document in its SAP Library structure

Definition

Shared memory is memory that can be accessed by more than one process. Almost all memory used by an Informix database is shared.

Use

You can use the database overview of the SAP/Informix database monitor to view shared memory.

If you are running Informix version 6, select Shared Memory Incl. from the main screen to display an overview of shared memory.

Structure

Informix divides its shared memory into the following classes:

Class

Description

Resident

The resident portion is fixed at startup and contains, among other objects, the data buffer and the log buffers.

Virtual

Important in the virtual portion are the session pools, that is, memory used for each session. The virtual portion of shared memory can also grow during normal business.

Message

The message portion is typically very small and not relevant for tuning.

 

See also:

SHMADD (Informix)

SHMTOTAL (Informix)

SHMVIRTSIZE (Informix)