Oracle Database 11g Oracle Real Application Clusters Handbook, 2nd Edition, 2nd Edition

Using Automatic Segment Space Management

Automatic Segment Space Management (ASSM) was introduced in Oracle 9i and is the preferred way to manage space within a segment. Oracle uses bitmaps stored within the segment to manage free space for the segment. This is a more efficient and simpler way to manage space within a segment compared to the traditional linked-list-based space management algorithm. The traditional method uses the PCTUSED, FREELISTS, and FREELIST GROUPS parameters for managing space usage for tables, indexes, and so on. Using ASSM also provides dynamic affinity of space to instances, because there is no association of extents to instances as there is while using FREELIST GROUPS. Therefore, there is no performance degradation or ...