DS_TOTAL_MEMORY configuration parameter

Use the DS_TOTAL_MEMORY configuration parameter to specify the amount of memory available for PDQ queries. The amount should be smaller than the computer physical memory, minus fixed overhead such as operating-system size and buffer-pool size.

onconfig.std value
Not set.
if not present
If SHMTOTAL=0 and DS_MAX_QUERIES is set, DS_TOTAL_MEMORY = DS_MAX_QUERIES * 128.

If SHMTOTAL=0 and DS_MAX_QUERIES is not set, DS_TOTAL_MEMORY = num_cpu_vps * 2 * 128.

values
If DS_MAX_QUERIES is set, the minimum value is DS_MAX_QUERIES * 128.

If DS_MAX_QUERIES is not set, the minimum value is num_cpu_vps * 2 * 128.

There is no maximum value limit other than any limit that you might have with the software that you use on your machine.

units
Kilobytes
takes effect
After you edit your onconfig file and restart the database server.
When you reset the value dynamically in your onconfig file by running the onmode -wf command.
When you reset the value in memory by running the onmode -wm command.

Usage

Do not confuse DS_TOTAL_MEMORY with the configuration parameters SHMTOTAL and SHMVIRTSIZE. The SHMTOTAL setting specifies all the memory for the database server (total of the resident, virtual, and message portions of memory). The SHMVIRTSIZE setting specifies the size of the virtual portion. DS_TOTAL_MEMORY is a logical subset of SHMVIRTSIZE.

For OLTP applications, set DS_TOTAL_MEMORY to between 20 and 50 percent of the value of SHMTOTAL in kilobytes.

For applications that involve large decision-support (DSS) queries, increase the value of DS_TOTAL_MEMORY to between 50 and 80 percent of SHMTOTAL. If you use your database server for DSS queries exclusively, set this parameter to 90 and 100 percent of SHMTOTAL.

Set the DS_TOTAL_MEMORY configuration parameter to any value not greater than the quantity (SHMVIRTSIZE - 10 megabytes).

For information on the maximum memory available on your platform, see the machine notes.


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