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Oracle

1Z0-052 · Question #69

Your database instance is started using the server parameter file (SPFILE). You executed a command to change the value of the LOG_BUFFER initialization parameter: ALTER SYSTEM SET LOG_BUFFER=32M…

The correct answer is C. The command returns an error because the size of the redo log buffer cannot be changed dynamically. LOG_BUFFER is a static initialization parameter in Oracle Database and cannot be modified dynamically while the instance is running. Any attempt to use SCOPE=BOTH or SCOPE=MEMORY will result in an ORA error.

Managing the Database Instance

Question

Your database instance is started using the server parameter file (SPFILE). You executed a command to change the value of the LOG_BUFFER initialization parameter:

ALTER SYSTEM SET LOG_BUFFER=32M SCOPE=BOTH; What would be the outcome of this command?

Options

  • AThe command succeeds only if Automatic Memory Management is not enabled.
  • BThe command succeeds, but you need to restart the database for changes to take effect.
  • CThe command returns an error because the size of the redo log buffer cannot be changed dynamically.
  • DThe parameter value is changed and it comes into effect as soon as space becomes available in the

How the community answered

(49 responses)
  • A
    14% (7)
  • B
    4% (2)
  • C
    71% (35)
  • D
    10% (5)

Why each option

LOG_BUFFER is a static initialization parameter in Oracle Database and cannot be modified dynamically while the instance is running. Any attempt to use SCOPE=BOTH or SCOPE=MEMORY will result in an ORA error.

AThe command succeeds only if Automatic Memory Management is not enabled.

Whether Automatic Memory Management is enabled is irrelevant to LOG_BUFFER's static nature - the command fails regardless of the AMM configuration.

BThe command succeeds, but you need to restart the database for changes to take effect.

The command does not succeed at all because SCOPE=BOTH attempts an in-memory change, which is illegal for a static parameter - SCOPE=SPFILE would be required to defer the change to the next restart.

CThe command returns an error because the size of the redo log buffer cannot be changed dynamically.Correct

LOG_BUFFER is classified as a static parameter, meaning it can only be changed in the SPFILE using SCOPE=SPFILE, and the change takes effect only after a full database restart. Using SCOPE=BOTH attempts to apply the change to the running instance's memory, which Oracle explicitly prohibits for static parameters, causing the command to fail with an error such as ORA-02095.

DThe parameter value is changed and it comes into effect as soon as space becomes available in the

LOG_BUFFER is a fixed-size buffer allocated at instance startup and has no mechanism to dynamically expand when space becomes available - its value is determined solely at startup.

Concept tested: Oracle static vs dynamic initialization parameters

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

Topics

#LOG_BUFFER#static parameters#SPFILE#ALTER SYSTEM

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