Learning PHP-MySQL高级管理_PHP_编程开发_程序员俱乐部

引用mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables;
+---------------------------+
| Tables_in_mysql           |
+---------------------------+
| columns_priv              |
| db                        |
| event                     |
| func                      |
| general_log               |
| help_category             |
| help_keyword              |
| help_relation             |
| help_topic                |
| host                      |
| ndb_binlog_index          |
| plugin                    |
| proc                      |
| procs_priv                |
| proxies_priv              |
| servers                   |
| slow_log                  |
| tables_priv               |
| time_zone                 |
| time_zone_leap_second     |
| time_zone_name            |
| time_zone_transition      |
| time_zone_transition_type |
| user                      |
+---------------------------+
24 rows in set (0.00 sec)
以上每个表都存储了关于系统给的信息。保存权限信息的的6个表分别是：user、host、db、tables_priv和columns_priv以及procs_priv。有时，这些表也称为授权表（grant tables）
引用user表和host表用于确定一个用户是否可以连接MySQL服务器，以及该用户是否具有任何管理员权限。db表和host表确定用户可以访问哪些数据库。tables_priv表确定用户可以使用数据库中的哪些表，而columns_priv表确定用户可以访问表中的哪些列，procs_priv表确定用户可以执行哪些过程。
更新权限：修改什么时候生效

• 1、flush privileges
• 2、mysqladmin flush-privileges
• 3、mysqladmin reload

从操作系统角度来保护MySQL
创建一个专门用来运行mysqld的特定MySQL用户是一个好主意。此外，还可建立只能够由MySQL用户访问的目录。
使用show获取信息：
引用mysql> help show;
Name: 'SHOW'
Description:
SHOW has many forms that provide information about databases, tables,
columns, or status information about the server. This section describes
those following:

SHOW AUTHORS
SHOW {BINARY | MASTER} LOGS
SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
SHOW CHARACTER SET [like_or_where]
SHOW COLLATION [like_or_where]
SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]
SHOW CONTRIBUTORS
SHOW CREATE DATABASE db_name
SHOW CREATE EVENT event_name
SHOW CREATE FUNCTION func_name
SHOW CREATE PROCEDURE proc_name
SHOW CREATE TABLE tbl_name
SHOW CREATE TRIGGER trigger_name
SHOW CREATE VIEW view_name
SHOW DATABASES [like_or_where]
SHOW ENGINE engine_name {STATUS | MUTEX}
SHOW [STORAGE] ENGINES
SHOW ERRORS [LIMIT [offset,] row_count]
SHOW EVENTS
SHOW FUNCTION CODE func_name
SHOW FUNCTION STATUS [like_or_where]
SHOW GRANTS FOR user
SHOW INDEX FROM tbl_name [FROM db_name]
SHOW MASTER STATUS
SHOW OPEN TABLES [FROM db_name] [like_or_where]
SHOW PLUGINS
SHOW PROCEDURE CODE proc_name
SHOW PROCEDURE STATUS [like_or_where]
SHOW PRIVILEGES
SHOW [FULL] PROCESSLIST
SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]
SHOW PROFILES
SHOW SLAVE HOSTS
SHOW SLAVE STATUS
SHOW [GLOBAL | SESSION] STATUS [like_or_where]
SHOW TABLE STATUS [FROM db_name] [like_or_where]
SHOW [FULL] TABLES [FROM db_name] [like_or_where]
SHOW TRIGGERS [FROM db_name] [like_or_where]
SHOW [GLOBAL | SESSION] VARIABLES [like_or_where]
SHOW WARNINGS [LIMIT [offset,] row_count]

like_or_where:
    LIKE 'pattern'
  | WHERE expr

If the syntax for a given SHOW statement includes a LIKE 'pattern'
part, 'pattern' is a string that can contain the SQL "%" and "_"
wildcard characters. The pattern is useful for restricting statement
output to matching values.

Several SHOW statements also accept a WHERE clause that provides more
flexibility in specifying which rows to display. See
http://dev.mysql.com/doc/refman/5.5/en/extended-show.html.

URL: http://dev.mysql.com/doc/refman/5.5/en/show.html
用explain理解查询操作的工作过程
有两种方式可以调用explain语句

• 第一种：explain table；
• 第二种：可以使用explain语句来查看MySQL是如何来解释并执行一个SELECT查询。

引用mysql> help explain;
Name: 'EXPLAIN'
Description:
Syntax:
EXPLAIN [explain_type] SELECT select_options

explain_type:
    EXTENDED
  | PARTITIONS

Or:

EXPLAIN tbl_name

The EXPLAIN statement can be used either as a way to obtain information
about how MySQL executes a statement, or as a synonym for DESCRIBE:

o When you precede a SELECT statement with the keyword EXPLAIN, MySQL
  displays information from the optimizer about the query execution
  plan. That is, MySQL explains how it would process the statement,
  including information about how tables are joined and in which order.
  EXPLAIN EXTENDED can be used to obtain additional information.

  For information about using EXPLAIN and EXPLAIN EXTENDED to obtain
  query execution plan information, see
  http://dev.mysql.com/doc/refman/5.5/en/using-explain.html.

o EXPLAIN PARTITIONS is useful only when examining queries involving
  partitioned tables. For details, see
  http://dev.mysql.com/doc/refman/5.5/en/partitioning-info.html.

o EXPLAIN tbl_name is synonymous with DESCRIBE tbl_name or SHOW COLUMNS
  FROM tbl_name. For information about DESCRIBE and SHOW COLUMNS, see
  [HELP DESCRIBE], and [HELP SHOW COLUMNS].

URL: http://dev.mysql.com/doc/refman/5.5/en/explain.html
使用analyze table
引用mysql> help analyze table;
Name: 'ANALYZE TABLE'
Description:
Syntax:
ANALYZE [NO_WRITE_TO_BINLOG | LOCAL] TABLE
    tbl_name [, tbl_name] ...

ANALYZE TABLE analyzes and stores the key distribution for a table.
During the analysis, the table is locked with a read lock for InnoDB
and MyISAM. This statement works with InnoDB, NDB, and MyISAM tables.
For MyISAM tables, this statement is equivalent to using myisamchk
--analyze.

For more information on how the analysis works within InnoDB, see
http://dev.mysql.com/doc/refman/5.5/en/innodb-restrictions.html.

MySQL uses the stored key distribution to decide the order in which
tables should be joined when you perform a join on something other than
a constant. In addition, key distributions can be used when deciding
which indexes to use for a specific table within a query.

This statement requires SELECT and INSERT privileges for the table.

ANALYZE TABLE is supported for partitioned tables, and you can use
ALTER TABLE ... ANALYZE PARTITION to analyze one or more partitions;
for more information, see [HELP ALTER TABLE], and
http://dev.mysql.com/doc/refman/5.5/en/partitioning-maintenance.html.

URL: http://dev.mysql.com/doc/refman/5.5/en/analyze-table.html
数据库的优化

• 设计优化：如果可能，尽量避免使用可变长度列(想VARCHAR、TEXT和BLOB)。如果字段长度固定，它们用起来将更快，但是要占用多一点的空间。
• 权限：简化权限提高查询速度。在执行之前通过权限系统检查该查询的过程，该过程越简单，查询速度越快。
• 表的优化：使用 optimize table tablename；
• 使用索引：简化索引，不要创建查询不使用的索引。
• 使用默认值：在尽可能的地方使用列的默认值，只在于默认值不同的时候才插入数据。这样可以减少执行INSERT语句所花的时间。

备份MySQL数据库

• 第一种方式是在复制数据文件时候使用LOCK TABLES命令锁定这些表
LOCK TABLES table lock_type[, table lock_type …]
每一个表必须是表的名称，而锁定类型可是是READ或WRITE。对于备份来说，只需要READ锁。在执行备份之前。必须执行FLUSH TABLES；命令来确定对索引所做的任何修改将写入磁盘。
• 第二种方法是使用mysql_dump命令。
mysqldump --opt --all-databases > all.sql
• 第三种方法是使用mysqlhotcopy脚本
mysqlhotcopy database /path/for/backup

恢复MySQL数据库
如果出现了一个破坏了的表，可以运行带有-r选项的myismchk命令。
如果使用了第一种方法执行备份，可以将数据文件重新复制到安装MySQL的相同位置。
如果使用了第二种方式执行备份，数据库的恢复就需要执行一些操作。首先，必须在导出文件中运行查询。这可以将数据库重新构建至导出该文件时的状态。接着，还应该将数据库更新至保存在二进制日子文件中的状态。

class="mysql">mysqlbinlog hostname-bin.[0-9]* |mysql

参考资料：
PHP&MySQL.Web