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.
Set the operating-system parameters for maximum shared-memory segment size, typically SHMMAX, SHMSIZE, or SHMALL, to the total size that your database server configuration requires. For information on the amount of shared memory that your operating system allows, see the machine notes.