标签：更改 实例 timezone 函数 sub evel time sample wal
user: User accounts, global privileges, and other non-privilege columns. db: Database-level privileges. tables_priv: Table-level privileges. columns_priv: Column-level privileges. procs_priv: Stored procedure and function privileges. proxies_priv: Proxy-user privileges.
基本上每一个系统表都会包含有权限列和范围列，也就包含一些授权的主要信息表。
general_log: The general query log table. slow_log: The slow query log table.
这两张系统表可以将慢日志和日志按照表格的形式存储下来，但是相对来说带来对性能和存储空间的使用更大，一般生产环境我们都建议设置为外部文件。
help_category: Information about help categories. help_keyword: Keywords associated with help topics. help_relation: Mappings between help keywords and topics. help_topic: Help topic contents.
这些表存储了mysql帮助的基本信息，我们都可以用HELP +列 来查看具体的帮助信息。
time_zone: Time zone IDs and whether they use leap seconds. time_zone_leap_second: When leap seconds occur. time_zone_name: Mappings between time zone IDs and names. time_zone_transition, time_zone_transition_type: Time zone descriptions.
设置时区用以下方式：SET GLOBAL time_zone = timezone;
| Column name | Description |
| database_name | Database name |
| table_name | Table name, partition name, or subpartition name |
| last_update | A timestamp indicating the last time that InnoDB updated this row |
| n_rows | The number of rows in the table |
| clustered_index_size | The size of the primary index, in pages |
| sum_of_other_index_sizes | The total size of other (non-primary) indexes, in pages |
| Column name | Description |
| database_name | Database name |
| table_name | Table name, partition name, or subpartition name |
| index_name | Index name |
| last_update | A timestamp indicating the last time that InnoDB updated this row |
| stat_name | The name of the statistic, whose value is reported in the stat_value column |
| stat_value | The value of the statistic that is named in stat_name column |
| sample_size | The number of pages sampled for the estimate provided in the stat_value column |
| stat_description | Description of the statistic that is named in the stat_name column |
SELECT SUM(stat_value) pages, index_name, SUM(stat_value)*@@innodb_page_size size FROM mysql.innodb_index_stats WHERE table_name=‘t1‘ AND stat_name = ‘size‘ GROUP BY index_name; SELECT index_name, stat_name, stat_value, stat_description FROM mysql.innodb_index_stats WHERE table_name like ‘t1‘; SELECT index_name, stat_name, stat_value, stat_description FROM mysql.innodb_index_stats WHERE table_name like ‘t1‘ AND stat_name LIKE ‘n_diff%‘;
server_cost：服务器操作的成本估算信息
标签：更改 实例 timezone 函数 sub evel time sample wal
原文地址：http://www.cnblogs.com/shengdimaya/p/6919055.html
