8 Monitoring and Managing Memory

- Describe the memory components in the SGA.
- Implement Automatic Shared Memory Management.
- Configure automatic PGA memory management.
- Memory Management: Overview.
- DBAs must consider memory management to be a crucial part of their job because:.
- Java pool Database buffer cache Shared pool.
- Redo log buffer Large pool Streams pool.
- Keep buffer cache Recycle buffer cache nK block size buffer caches.
- Buffer Cache.
- DB buffer cache.
- Shared pool Library.
- cache UGA Shared pool.
- Shared pool.
- Size is specified by using SHARED_POOL_SIZE.
- Shared Pool.
- Shared pool Database.
- buffer cache Redo log.
- Large pool.
- Large Pool.
- Library cache.
- Can be configured as a separate memory area in the SGA.
- Is sized by the LARGE_POOL_SIZE parameter.
- Java Pool.
- Is sized by the JAVA_POOL_SIZE parameter.
- buffer Library cache Large pool.
- Dictionary cache Java pool.
- Redo Log Buffer.
- Shared pool Redo log.
- buffer cache Library cache.
- Automatic Shared Memory Management:.
- Buffer cache Large pool Shared pool.
- Java pool.
- Buffer cache Large pool Shared pool Java pool Online users Batch jobs Streams pool Streams pool Example:.
- Benefits of Automatic Shared Memory Management.
- DB_CACHE_SIZE.
- SHARED_POOL_SIZE LARGE_POOL_SIZE JAVA_POOL_SIZE.
- STREAMS_POOL_SIZE.
- SGA_TARGET.
- SGA_TARGET = 8G.
- Total SGA size = 8 GB Java pool.
- Database buffer cache.
- Redo log buffer Shared pool.
- Large pool Fixed SGA.
- Streams pool.
- When SGA_TARGET is not set or is set to zero:.
- SHARED_POOL_SIZE may need to be increased from settings used in earlier database versions.
- When SGA_TARGET is set to a nonzero value:.
- FROM v$sgastat WHERE pool = 'shared pool';.
- The memory used by these components reduces the amount of memory available for autotuning the SGA..
- DB_CACHE_SIZE = 0 JAVA_POOL_SIZE = 0 LARGE_POOL_SIZE = 0 SHARED_POOL_SIZE = 0 STREAMS_POOL_SIZE = 0.
- Modifying the SGA_TARGET Parameter.
- The SGA_TARGET initialization parameter:.
- A change in the value of SGA_TARGET affects only automatically sized components..
- Setting SGA_TARGET to zero disables autotuning..
- The SGA size as a whole is unaffected..
- sga_target = 8G.
- shared_pool_size = 1G.
- sga_target = 0.
- db_cache_size = 5G shared_pool_size = 2G large_pool_size = 512M java_pool_size = 256M streams_pool_size = 256M SGA size = 8 GB.
- Resizing manually tuned parameters affects only the tunable portion of the SGA..
- Shared pool or.
- large pool.
- Automatic PGA Memory Management.
- Using the Memory Advisor to Size the SGA.
- Try to fit the SGA into physical memory..
- Tune for a high buffer cache hit ratio, with the following caveats:.
- Use automatic PGA memory management.
- Enabling Automatic Shared Memory Management

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