onmode -a: Add a shared-memory segment

Ordinarily, you do not need to add segments to the virtual portion of shared memory because the database server automatically adds segments as they are needed. However, as segments are added, the database server might reach the operating-system limit for the maximum number of segments before it acquires the memory that it needs. This situation typically occurs when the SHMADD configuration parameter is set so small that the database server exhausts the number of available segments before it acquires the memory that it needs for some operation.

You can use this command to add a segment that is larger than the size specified by the SHMADD configuration parameter. By using this command to add a segment, you can adhere to the operating system limit for segments while meeting the need that the database server has for additional memory.

This command has an equivalent SQL administration API function.