Row compression not reducing disk storage space for temporary tables

There are known situations that might occur which result in a lack of expected savings in disk storage space for temporary tables even though the Storage Optimization feature is licensed.

Symptoms

Potential disk space savings by enabling row compression on temporary tables are not being realized as expected.

Causes

This situation occurs mostly as a result of a large number of applications running at the same time and creating temporary tables, each of which consumes a portion of the database manager memory. This results in not enough memory being available to create the compression dictionary. Notification is not given when this situation occurs.
Rows are compressed using a dictionary-based approach according to an algorithm. If a row of a temporary table is large enough to yield appreciable savings in disk space, the row will be compressed. Small rows in temporary tables will not be compressed and this will account for the lack of expected savings in disk storage space. Notification is not given when this situation occurs.

Risk

There is no risk to the system aside from row compression not being used on temporary tables with row sizes that do not meet the threshold. There could be other adverse effects to the database manager if available memory remains highly constricted.