Automatic Shared Memory Management (ASMM)

With manual configuration, it is possible for compiled SQL statements to frequently age out of the shared pool due to inadequate size. With automatic SGA management, the internal tuning algorithm monitors the workload performance and increases the shared pool as needed to reduce the number of parses.

The ASMM feature uses a new Memory Manager (MMAN) background process. MMAN coordinates the sizing of the memory components and acts as a memory broker. The MMAN keeps track of all memory components and pending resize operations.

Based on workload information from AWR, the ASMM can capture statistics periodically, every 60 minutes for example, in the background, use different memory advisories, and move memory to where it is most needed whether that be the large pool or buffer cache. For example in a long running OLTP day job, a larger buffer cache is needed; while for a data warehousing (DSS) batch job at night, more memory is needed for the large pool. The ASMM moves the memory to buffer cache or large pool as needed.