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1Z0-052 · Question #53

Automatic Shared Memory Management (ASMM) has been enabled for your database instance. The initialization parameters for the components that are managed by ASMM are not set. After observing the…

The correct answer is A. The minimum memory size for the database buffer cache is set to 100 MB. When ASMM is active and a component parameter like DB_CACHE_SIZE is set to a non-zero value, it establishes the minimum guaranteed allocation for that SGA component, not a maximum.

Managing the Database Instance

Question

Automatic Shared Memory Management (ASMM) has been enabled for your database instance. The initialization parameters for the components that are managed by ASMM are not set. After observing the effects of ASMM, you executed the following command:

SQL> ALTER SYSTEM SET DB_CACHE_SIZE = 100M; Which statement is true in this scenario?

Options

  • AThe minimum memory size for the database buffer cache is set to 100 MB.
  • BThe maximum memory size that can be obtained by the database buffer cache during ASMM is
  • CThe minimum memory size allocated for a server process in the database buffer cache in dedicated
  • DThe maximum memory size from the database buffer cache that can be released for dynamic

How the community answered

(37 responses)
  • A
    81% (30)
  • B
    3% (1)
  • C
    5% (2)
  • D
    11% (4)

Why each option

When ASMM is active and a component parameter like DB_CACHE_SIZE is set to a non-zero value, it establishes the minimum guaranteed allocation for that SGA component, not a maximum.

AThe minimum memory size for the database buffer cache is set to 100 MB.Correct

Under ASMM (SGA_TARGET > 0), explicitly setting DB_CACHE_SIZE=100M tells Oracle that the database buffer cache must never shrink below 100 MB. ASMM can still dynamically grow the cache beyond 100 MB based on workload demand, but 100 MB is the guaranteed minimum floor it will maintain.

BThe maximum memory size that can be obtained by the database buffer cache during ASMM is

Setting DB_CACHE_SIZE under ASMM imposes a minimum floor, not a ceiling - ASMM is free to grant the buffer cache more than 100 MB if workload demands it.

CThe minimum memory size allocated for a server process in the database buffer cache in dedicated

DB_CACHE_SIZE controls the size of the shared buffer cache pool in the SGA, not the memory allocated to individual dedicated server processes.

DThe maximum memory size from the database buffer cache that can be released for dynamic

The parameter sets a minimum that ASMM cannot release below, meaning it restricts how much can be released, not the maximum releasable amount.

Concept tested: ASMM minimum component size via DB_CACHE_SIZE

Source: https://docs.oracle.com/en/database/oracle/oracle-database/19/refrn/DB_CACHE_SIZE.html

Topics

#ASMM#DB_CACHE_SIZE#database buffer cache#SGA management

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