| SNAP_ID | NUMBER | NOT NULL | Unique snapshot ID | 
| DBID | NUMBER | NOT NULL | Database ID for the snapshot | 
| INSTANCE_NUMBER | NUMBER | NOT NULL | Instance number for the snapshot | 
| CATEGORY | VARCHAR2(15) | NOT NULL | Category name. Categories include "SQL", "PL/SQL", "OLAP" and "JAVA". Special categories are "Freeable" and "Other". Freeable memory has been allocated to the process by the operating system, but has not been allocated to a category. "Other" memory has been allocated to a category, but not to one of the named categories | 
| NUM_PROCESSES | NUMBER |  | Number of processes | 
| NON_ZERO_ALLOCS | NUMBER |  | Number of processes with non-zero allocations | 
| USED_TOTAL | NUMBER |  | Bytes of PGA memory used by the process for the category | 
| ALLOCATED_TOTAL | NUMBER |  | Total number of bytes of PGA memory allocated by the process for the category. | 
| ALLOCATED_AVG | NUMBER |  | Average number of bytes of PGA memory allocated by the process for the category | 
| ALLOCATED_STDDEV | NUMBER |  | Standard deviation of the number of bytes of PGA memory allocated by the process for the category | 
| ALLOCATED_MAX | NUMBER |  | Maximum bytes of PGA memory ever allocated by the process for the category | 
| MAX_ALLOCATED_MAX | NUMBER |  | Maximum bytes of PGA memory that can be allocated by the process for the category |