6.8 Memory Management Reference

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Automatic memory management is supported only on some platforms. Also, you can query a set of data dictionary views for information on memory management.

◉ Platforms That Support Automatic Memory Management

Some platforms support automatic memory management.

The following platforms support automatic memory management—the Oracle Database ability to automatically tune the sizes of the SGA and PGA, redistributing memory from one to the other on demand to optimize performance:
  • Linux
  • Solaris
  • Windows
  • HP-UX
  • AIX

◉ Memory Management Data Dictionary Views

A set of dynamic performance views provide information on memory management.

View Description
V$SGA Displays summary information about the system global area (SGA).
V$SGAINFO Displays size information about the SGA, including the sizes of different SGA components, the granule size, and free memory.
V$SGASTAT Displays detailed information about how memory is allocated within the shared pool, large pool, Java pool, and Streams pool.
V$PGASTAT Displays PGA memory usage statistics as well as statistics about the automatic PGA memory manager when it is enabled (that is, when PGA_AGGREGATE_TARGET is set). Cumulative values in V$PGASTAT are accumulated since instance startup.
V$MEMORY_DYNAMIC_COMPONENTS Displays information on the current size of all automatically tuned and static memory components, with the last operation (for example, grow or shrink) that occurred on each.
V$SGA_DYNAMIC_COMPONENTS Displays the current sizes of all SGA components, and the last operation for each component.
V$SGA_DYNAMIC_FREE_MEMORY Displays information about the amount of SGA memory available for future dynamic SGA resize operations.
V$MEMORY_CURRENT_RESIZE_OPS Displays information about resize operations that are currently in progress. A resize operation is an enlargement or reduction of the SGA, the instance PGA, or a dynamic SGA component.
V$SGA_CURRENT_RESIZE_OPS Displays information about dynamic SGA component resize operations that are currently in progress.
V$MEMORY_RESIZE_OPS Displays information about the last 800 completed memory component resize operations, including automatic grow and shrink operations for SGA_TARGET and PGA_AGGREGATE_TARGET.
V$SGA_RESIZE_OPS Displays information about the last 800 completed SGA component resize operations.
V$MEMORY_TARGET_ADVICE Displays information that helps you tune MEMORY_TARGET if you enabled automatic memory management.
V$SGA_TARGET_ADVICE Displays information that helps you tune SGA_TARGET.
V$PGA_TARGET_ADVICE Displays information that helps you tune PGA_AGGREGATE_TARGET.
V$IM_SEGMENTS Displays information about the storage allocated for all segments in the IM column store.
Note: This view is available starting with Oracle Database 12c Release 1 (

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