An application accesses a small lookup table frequently. You notice that the required data blocks
are getting aged out of the default buffer cache.
How would you guarantee that the blocks for the table never age out?
A.
Configure the KEEP buffer pool and alter the table with the corresponding storage clause.
B.
Increase the database buffer cache size.
C.
Configure the RECYCLE buffer pool and alter the table with the corresponding storage clause.
D.
Configure Automata Shared Memory Management.
E.
Explanation:
Schema objects are referenced with varying usage patterns; therefore, their cache
behavior may be quite different. Multiple buffer pools enable you to address these
differences. You can use a KEEP buffer pool to maintain objects in the buffer cache
and a RECYCLE buffer pool to prevent objects from consuming unnecessary space in the
cache. When an object is allocated to a cache, all blocks from that object are placed in
that cache. Oracle maintains a DEFAULT buffer pool for objects that have
not been assigned to one of the buffer pools.
There is only one choice for this question. The correct answer is A
A
A
A
A
The purpose of the KEEP buffer pool is to retain objects in memory, thus avoiding I/O operations. Each object kept in memory results in a trade-off. It is more beneficial to keep frequently-accessed blocks in the cache. Avoid retaining infrequently-used blocks in the cache, as this results in less space for other, more active blocks.
If there are certain segments in your application that are referenced frequently, then consider storing the blocks from those segments in the KEEP buffer pool. Typical segments that are kept in the KEEP pool are small, frequently-used reference tables.
You can configure a RECYCLE buffer pool for blocks belonging to those segments that you do not want to keep in memory. The purpose of the RECYCLE pool is to retain segments that are scanned rarely or are not referenced frequently. If an application randomly accesses the blocks of a very large object, then it is unlikely for a block stored in the buffer pool to be reused before it is aged out. This is true regardless of the size of the buffer pool (given the constraint of the amount of available physical memory). Consequently, the object’s blocks do not need to be cached; the cache buffers can be allocated to other objects.
The answer is : A
A
only A. Recycle pool is to put objects that should not stay in memory for long time, exactly the opposite of what the question requests.