SGA
The following views provide information about the System Global Area (SGA):
- *$CURRENT_BUCKET
Lists the number of increased buffer misses if the value of the DB_BLOCK_BUFFERS initialization parameter were to be reduced. Obsolete after Oracle 8.1. Available after database is opened.
- *$PGASTAT
Provides memory usage statistics that are used by the Oracle Memory Manager to allocate the maximum amount of memory a particular work area can have at any one time. New with Oracle9i.
- *$RECENT_BUCKET
Lists the number of increased buffer hits if the value of DB_BLOCK_BUFFERS were to be increased. See the initialization parameter DB_BLOCK_LRU_EXTENDED_STATISTICS in Chapter 2. Available after database is opened.
- *$SGA
Contains information about the size, in bytes, of each of the various SGA components.
- *$SGASTAT
Provides more detailed information about SGA utilization than *$SGA. Shows the breakdown of the SHARED_POOL and LARGE_POOL areas.
- *$SHARED_POOL_RESERVED
Contains statistics about the SHARED_POOL area of the SGA. Some of the columns are meaningful only if the initialization parameter SHARED_POOL_RESERVED_ SIZE has been set.
- *$VPD_POLICY
Lists all the security policies and predicates that are associated with the cursors that are currently in the library cache. (VPD stands for Virtual Private Database, which we describe in Chapter 4. VPDs can be used to implement completely separate logical databases in the same Oracle database using fine-grained security policies.)