10.6.2 Checking the usage status of the shared memory
To check the usage status of the shared memory, execute the adbls -d shm command on the HADB server. This displays the total amount of shared memory being used by the HADB server. This subsection explains when to check the usage status of the shared memory, how to check it, and what to do if the amount of free space becomes too small.
For details about the adbls -d shm command options and individual output items, see adbls -d shm (Display Shared Memory Information) in the manual HADB Command Reference.
- Organization of this subsection
(1) When to check the usage status of the shared memory
To ensure that the shared memory does not run out of free space, check the usage status of the shared memory regularly.
If the shared memory runs out of free space, an error message is output. Take the necessary corrective action according to the error message. When doing so, execute the adbls -d shm command to check the usage status of the shared memory.
(2) How to check the usage status of the shared memory
The following is an example of the shared memory usage status that is output when the adbls -d shm command is executed.
- ■ Shared memory usage status example
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SHM_NUMBER SHM_SIZE 8 1424683947
The following describes how to check the usage status of shared memory based on the above example.
- To check the usage status of shared memory:
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The amount of shared memory (in bytes) being used by the HADB server is displayed under SHM_SIZE. In this example, 1,424,683,947 bytes (approximately 1.4 gigabytes) is being used.
If the difference between this value and the value specified in the OS kernel parameter SHMMAX is small, the amount of available free space in the shared memory is considered insufficient. In this case, take action as explained in (3) Steps to take when the amount of free space in the shared memory is insufficient.
If the difference is large, no action is necessary because there seems to be enough free memory.
(3) Steps to take when the amount of free space in the shared memory is insufficient
If the difference between the value displayed under SHM_SIZE and the value specified in SHMMAX is small, you might need to increase the values specified for the OS kernel parameters SHMMAX, SHMMNI, and SHMALL.