Oracle Oracle Certifications 1Z0-874 Questions & Answers

• Question 31:

  Which are the effects of the following statement mysql> SET GLOBAL query_cache_limit = 2097152;

  A. Query results need to be at least 2MB in size to be cached in the Query Cache.

  B. Query results up to 2MB will be cached in the Query Cache.

  C. The total size of cached queries will be limited to 2MB.

  D. The statement will generate an error because query_cache_limit can only be set for a single connection.

  Correct Answer: B

• Question 32:

  In which ways can you set the query_cache_type option?

  A. You can set it in the configuration file and restart the server.

  B. You can set it at runtime for the entire server with the following statement: SET GLOBAL query_cache_type=[0|1|2]

  C. You can set it at runtime for the current connection with the following statement: SET SESSION query_cache_type=[0|1|2]

  Correct Answer: A

• Question 33:

  Consider the following:

  mysql> SHOW STATUS LIKE 'Qcache%';

  +-------------------------+--------+

  | Variable_name | Value |

  +-------------------------+--------+

  | Qcache_free_blocks | 87 |

  | Qcache_free_memory | 318442 |

  | Qcache_hits | 11224 |

  | Qcache_inserts | 19215 |

  | Qcache_lowmem_prunes | 437 |

  | Qcache_not_cached | 9155 |

  | Qcache_queries_in_cache | 240 |

  | Qcache_total_blocks | 924 |

  +-------------------------+--------+

  What can be derived from this output?

  A. There is a low utilization of the query cache.

  B. There is a normal utilization of the query cache.

  C. There is a high utilization of the query cache.

  Correct Answer: A

• Question 34:

  Which of the following statements about MEMORY tables are true?

  A. Creating many MEMORY tables should be avoided.

  B. It is OK to store large amounts of data in MEMORY tables.

  C. MEMORY tables should not be used to store large amounts of data.

  D. The number of MEMORY tables on a server will not cause any performance problems.

  Correct Answer: D

• Question 35:

  Which of the following is true of the table cache if you mainly run simple queries on many tables?

  A. The table cache should be decreased.

  B. The table cache should be increased.

  C. The table cache should not be changed.

  Correct Answer: B

• Question 36:

  By default, mysqld's memory settings are...

  A. There are no default memory settings for mysqld.

  B. Set to a median value good for overall general use.

  C. Rather consuming and should be decreased if possible.

  D. Rather conservative and should be increased if possible.

  Correct Answer: D

• Question 37:

  Is it a good idea to do periodic table rebuilds for InnoDB tables? Why?

  A. No, because the indexes have to be rebuilt.

  B. No, because there is a risk for data corruption.

  C. Yes, because it flushes the logs and frees memory.

  D. Yes, because the table may become fragmented after many INSERTs and DELETEs

  Correct Answer: D

• Question 38:

  Which of the following statements are true?

  A. A MERGE table cannot be used with compressed tables.

  B. A MERGE table may span across compressed and uncompressed tables.

  C. A MERGE table can only be a collection of either compressed or uncompressed tables.

  Correct Answer: B

• Question 39:

  Which of the following statements best describe the indexes supported by the MEMORY storage engine, and their general characteristics?

  A. MEMORY tables only support HASH indexes which provide fast lookups that use a unique index.

  B. MEMORY tables only support BTREE which provide better performance with non-unique index values and other comparison operators.

  C. MEMORY tables support HASH indexes which provide fast lookups that use a unique index, and BTREE indexes which provide better performance with non-unique index values and other comparison operators.

  D. MEMORY tables support HASH indexes which provide better performance with non-unique index values and other comparison operators, and BTREE indexes which provide fast lookups that use a unique index.

  Correct Answer: C

• Question 40:

  Which of the following best describes the relationship between MAX_ROWS, AVG_ROW_LENGTH and the max table size?

  A. MAX_ROWS * AVG_ROW_LENGTH tells MySQL how large you expect the table to grow to.

  B. MAX_ROWS + AVG_ROW_LENGTH tells MySQL to not let the table grow past that size.

  C. Specifying MAX_ROWS and AVG_ROW_LENGTH will prevent MySQL from growing the table beyond that limit.

  D. Specifying MAX_ROWS and AVG_ROW_LENGTH doesn't prevent MySQL from growing the table beyond that limit.

  Correct Answer: D