Using CA OLQ Efficiently › Controlling Resource Consumption › Sorts

Sorts

Sorting retrieved records is a resource-consuming operation. You can limit the ability to sort records to those users who need it.

You can control use of resources by controlling the use of sorts. There are two methods of sorting in CA OLQ:

• Using SORT after a GET/FIND command
• Using the ORDER BY clause of SELECT (OLQ access mode)

Using SORT after building a report with a GET/FIND command is costly. The ORDER BY clause of SELECT is more efficient because SELECT sorts the data while retrieving it.

When using SELECT (OLQ access mode), you can choose to disallow sorts altogether (this also disallows sorting with the ORDER BY clause of SELECT). To disallow sorting, use the IDD statement:

ADD/MODIFY USER ...
SORT IS NOT ALLOWED

Access mode: The SORT IS NOT ALLOWED clause is only valid when the access switch is set to OLQ.

Sort and the scratch area

CA OLQ sorts records in memory. The maximum amount of memory CA OLQ uses for any particular sort is determined by the SET MAXIMUM SORT SIZE system generation option. When sorting more records than fit into the maximum allowed, CA OLQ continues the sort by paging records in and out of scratch.

Specifying a large maximum sort size decreases the time a single sort takes and impacts other DC system users by:

• Using more storage
• Not releasing control to DC until the sort has completed

Note: If you want to use your own operating system sort facility when running a batch job, set up the proper job control language as described in num=11.Batch Processing.

For more information:

Batch Processing