Oracle 1Z0-873 Online Practice Questions and Exam Preparation

Oracle 1Z0-873 Online Questions & Answers

• Question 1:

  Which of the following best describes how MySQL utilizes the grant table buffers?

  A. The grant table buffer loads grant table information into memory for fast access.
  B. The grant table buffer loads what users are currently logged in and performing queries.
  C. The grant table buffer holds requests waiting to check the grant table to perform access-control.
  A. The grant table buffer loads grant table information into memory for fast access.

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  23.5. How MySQL Uses Memory

  The grant tables store information about MySQL user accounts and the privileges they have. The server loads a copy of the grant tables into memory for fast access-control checking.

• Question 2:

  Which of the following are true regarding the table cache?

  A. It is used to cache row data in open tables.
  B. It holds file descriptors for open tables.
  C. The size of the table cache may be set per-session
  D. Each connection has its own table cache. They are of equal size, set globally.
  E. There is one table cache, shared among all sessions.
  F. Increasing the size of the variable table_cache allows mysqld to keep more tables open simultaneously.
  B. It holds file descriptors for open tables.
  E. There is one table cache, shared among all sessions.
  F. Increasing the size of the variable table_cache allows mysqld to keep more tables open simultaneously.

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  39.3.1. Global (Server-Wide) Parameters

  This section discusses server parameters for resources that affect server performance as a whole or that are shared among clients.

  The table cache that holds information about tables that storage engines have open.

  39.3.1.2 The Table Cache

  When the server opens a table, it maintains information about that table in the table cache, which is used to avoid reopening tables when possible.

  Against this goal you must balance the fact that with a larger table cache the server requires more file descriptors. Operating systems place a limit on the number of file descriptors allowed to each process, so the table cache cannot be made arbitrarily large. However, some operating systems do allow the per- process file descriptor limit to be reconfigured.

• Question 3:

  Another user has issued LOCK TABLES pets READ You can...

  A. Update table pets
  B. SELECT from table pets
  C. UPDATE and SELECT from table pets
  D. None of the above
  B. SELECT from table pets

• Question 4:

  Which of the following features are supported by MyISAM tables?

  A. Foreign key constraints
  B. Transactions
  C. Auto_increment columns
  D. Fulltext indexes
  E. Assembly of multiple MyISAM tables to a MERGE table
  F. Row level locking
  G. Table level locking
  C. Auto_increment columns
  D. Fulltext indexes
  E. Assembly of multiple MyISAM tables to a MERGE table
  G. Table level locking

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  29.2. The MyISAM Engine

  MyISAM has the most flexible AUTO_INCREMENT column handling of all the storage engines.

  MyISAM tables can be used to set up MERGE tables.

  MyISAM tables can be converted into fast, compressed, read-only tables to save space. MyISAM supports FULLTEXT searching and spatial data types.

• Question 5:

  Suppose you want queries that are not using indexes to be logged to the slow log. How would you enable this?

  A. Use the --log-queries-indexes option.
  B. Use the --log-slow-queries-indexes option.
  C. Use the --log-queries-not-using-indexes option.
  D. Use the --log-slow-queries-not-using-indexes option.
  C. Use the --log-queries-not-using-indexes option.

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  24.5.3. The Slow Query Log

  To log queries that are not processed with the benefit of indexes, use the --log-queries-not-using- indexes option.

• Question 6:

  When working with InnoDB, for which of the following reasons should you use the FOR UPDATE locking modifier?

  A. You intend to run more than ten UPDATE statements in one transaction.
  B. You intend to execute an UPDATE statement on any row.
  C. You intend to SELECT a set of rows, then modify those rows.
  C. You intend to SELECT a set of rows, then modify those rows.

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  29.4.4. InnoDB Locking Characteristics With FOR UPDATE, InnoDB locks each selected row with an exclusive lock. This is useful if you intend to select and then modify a set of rows, because it prevents other transactions from reading or writing the rows until the first transaction releases the locks, which happens when the transaction finishes.

• Question 7:

  When working with InnoDB, which of the following are true of a parent / child foreign key relationship?

  A. The parent and child can have separate data types.
  B. The parent and child must have the same data type.
  C. The parent and child may sometimes need the same data type, but not always.
  B. The parent and child must have the same data type.

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  29.4.6. Using Foreign Keys

  In a foreign key relationship, the referring column and the referenced column should have the same data type, and both must be indexed. (If the referring column has no index, InnoDB creates an index on it automatically.)

• Question 8:

  The REPAIR TABLE command should be used...

  A. To improve performance by updating index distribution statistics.
  B. After multiple modifications to a tables data.
  C. To correct problems with a MyISAM table that have become corrupted.
  D. To check a tables structure to see if it may have been damaged and needs repair.
  C. To correct problems with a MyISAM table that have become corrupted.

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  30.2.2. REPAIR TABLE

  The REPAIR TABLE statement corrects problems in a table that has become corrupted. It works only for MyISAM tables.

• Question 9:

  Which of the following storage engines will ignore foreign keys if they are specified?

  A. MyISAM
  B. InnoDB
  C. HEAP
  D. MERGE
  E. FEDERATED
  A. MyISAM
  C. HEAP
  D. MERGE
  E. FEDERATED

• Question 10:

  The my.cnf file contains the following entries:

  innodb_data_home_dir =

  innodb_data_file_path = /ibdata/ibdata1:50M;/disk2/ibdata2:50M:autoextend

  Which of the following statements are true?

  A. The data files will be stored below the default data directory
  B. There are two InnoDB data files
  C. There are three InnoDB data files
  D. The total minimum size of the InnoDB data files is 100MB
  E. The total maximum size of the InnoDB data files is 100MB
  F. The initial size of the InnoDB data files on server startup will be set to 50MB. If more space is needed, another 50MB will be allocated.
  B. There are two InnoDB data files
  D. The total minimum size of the InnoDB data files is 100MB

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  29.4.7.1 Configuring the InnoDB Tablespace

  A tablespace consisting of a single 100MB file named innodata1 located in the data directory:

  [mysqld]

  innodb_data_file_path = innodata1:100M

  It's unnecessary to specify a value for the innodb_data_home_dir option in this case because the data directory is its default value.

  A tablespace like that in the previous example, except that the file is auto-extending:

  [mysqld]

  innodb_data_file_path = innodata1:100M:autoextend

  A tablespace like that in the previous example, but with a limit of 500MB on the size to which the autoextending

  file may grow:

  [mysqld]

  innodb_data_file_path = innodata1:100M:autoextend:max:500M