SHMTOTAL

onconfig.std
value

0

units

Kilobytes

range of values

Integer greater than or equal to 0

takes effect

When shared memory is initialized

utilities

onutil

refer to

How much shared memory the database server needs in the shared-memory chapter of the IBM Informix: Administrator's Guide

SHMTOTAL specifies the total amount of shared memory (resident, virtual, communications, and virtual extension portions) to be used by the database server for all memory allocations. The onconfig.std value of 0 implies that no limit on memory allocation is stipulated.

SHMTOTAL enables you to limit the demand for memory that the database server can place on your system. However, applications might fail if the database server requires more memory than the limit imposed by SHMTOTAL. When this situation occurs, the database server writes the following message in the message log:

size of resident + virtual segments xx + yy > zz 
total allowed by configuration parameter SHMTOTAL

This message includes the following values.

Value

Description

xx

Current size of resident segments

yy

Current size of virtual segments

zz

Total shared memory required

To modify the SHMTOTAL parameter dynamically, use the onutil SET command. Example:

%onutil
SET SHMTOTAL 10000000;