Database-Oracle [3i Infotech Placement]: Sample Questions 93 - 94 of 132

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Question 93

Oracle
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Describe in Detail

Essay▾

What is Oracle Block? Can two Oracle Blocks have the same address?

Explanation

Given Oracle Data Block and Operating System Blocks
  • Oracle “formats” the database files into a number of Oracle blocks when they are first created making it easier for the RDBMS software to manage the files and easier to read data into the memory areas
  • The block size should be a multiple of the operating system block size.
  • Regardless of the block size, the entire block is not available for holding data; Oracle takes up some space to manage the contents of the block.
  • This block header has a minimum size, but it can grow.
  • These Oracle blocks are the smallest unit of storage.
  • Increasing the Oracle block size can improve performance, but it should be done only when the database is first created.
  • Two blocks can have the same block address if they are in different database files.

Question 94

Oracle

Question

MCQ▾

ENQUEUE resources parameter information is derived from … .

Choices

Choice (4)

a.

LOG_BUFFER

b.

DB_BLOCK_SIZE

c.

Processes or DDL_LOCKS and DML_LOCKS

d.

Question does not provide sufficient data or is vague

Answer

c.

Explanation

Two Types of Locks

  1. DML lock
  2. DDL lock
Two Types of Locks
  • The dba_dml_locks and dba_ddl_locks views are both created by the catblock. sql script and are used to monitor DML and DDL locks
  • Parameter information is derived from Processes or DDL_LOCKS and DML_LOCKS.
  • Sets the number of resources it can be lock concurrently by the lock manager.
  • Oracle allocates the number of enqueuse specified by the ENQUEUE_RESOURCES parameter, at database startup time.
  • If we explicit set ENQUEUE_RESOURCES to a value higher than DML_LOCK, then oracle uses the value we provide.

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