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MySQL同步故障�Q? Slave_SQL_Running:No" 两种解决办法

liangcmwn — Tue, 16 Aug 2011 01:31:00 GMT

�q�入slave服务器，�q�行�Q?/p>

mysql> show slave status\G

         .......
             Relay_Log_File: localhost-relay-bin.000535
              Relay_Log_Pos: 21795072
      Relay_Master_Log_File: localhost-bin.000094
           Slave_IO_Running: Yes
          Slave_SQL_Running: No
            Replicate_Do_DB:
        Replicate_Ignore_DB:
      ......

解决办法一�?/strong>

Slave_SQL_Running: No
1.�E�序可能在slave上进行了(ji��n)写操�?/p>

2.也可能是slave机器重�v后，事务回滚造成�?

一般是事务回滚造成的：(x��)
解决办法�Q?br style="line-height: 22px; " />mysql> slave stop;
mysql> set GLOBAL SQL_SLAVE_SKIP_COUNTER=1;
mysql> slave start;

解决办法二�?/p>

首先停掉Slave服务�Q�slave stop
��C��服务器上查看��L��状态：(x��)
记录File和Position对应的�?/p>

�q�入master

然后到slave服务器上执行手动同步�Q?br style="line-height: 22px; " />mysql> change master to > master_host='master_ip', > master_user='user', > master_password='pwd', > master_port=3306, > master_log_file=localhost-bin.000094', > master_log_pos=33622483 ; 1 row in set (0.00 sec) mysql> slave start; 1 row in set (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
........
            Master_Log_File: localhost-bin.000094
        Read_Master_Log_Pos: 33768775
             Relay_Log_File: localhost-relay-bin.000537
              Relay_Log_Pos: 1094034
      Relay_Master_Log_File: localhost-bin.000094
           Slave_IO_Running: Yes
          Slave_SQL_Running: Yes
            Replicate_Do_DB:

手动同步需要停止master的写操作�Q?nbsp;

liangcmwn 2011-08-16 09:31 发表评论

liangcmwn — Tue, 16 Aug 2011 01:15:00 GMT

我们知道�Q�在关系数据�?/strong>标准中有四个事务隔离�U�别�Q?/p>
未提交读(Read Uncommitted)�Q�允许脏读，也就是可能读取到其他�?x��)话中未提交事务修改的数�?/li>
提交�?Read Committed)�Q�只能读取到已经提交的数据。Oracle�{�多数数据库默认都是该��?/li>
可重复读(Repeated Read)�Q�可重复诅R��在同一个事务内的查询都是事务开始时��M��致的�Q?strong style="word-break: break-all; line-height: normal; ">InnoDB默认�U�别。在SQL标准中，该隔��ȝ�别消除了(ji��n)不可重复读，但是�q�存在��象读
串行�?Serializable)�Q�完全串行化的读�Q�每�ơ读都需要获得表�U�共享锁�Q�读写相互都�?x��)阻�?/li>
查看InnoDB�pȝ��U�别的事务隔��ȝ�别：(x��)
mysql> SELECT @@global.tx_isolation;
+-----------------------+
| @@global.tx_isolation |
+-----------------------+
| REPEATABLE-READ |
+-----------------------+
1 row in set (0.00 sec)
查看InnoDB�?x��)话�U�别的事务隔��ȝ�别：(x��)
mysql> SELECT @@tx_isolation;
+-----------------+
| @@tx_isolation |
+-----------------+
| REPEATABLE-READ |
+-----------------+
1 row in set (0.00 sec)
修改事务隔离�U�别�Q?/p>
mysql> set global transaction isolation level read committed;
Query OK, 0 rows affected (0.00 sec)

mysql> set session transaction isolation level read committed;
Query OK, 0 rows affected (0.00 sec)
InnoDB的可重复读隔��ȝ�别和其他数据库的可重复读是有区别的，不会(x��)造成�q�象读（phantom read�Q�，所谓��象读�Q�就是同一个事务内�Q�多�ơselect�Q�可以读取到其他session insert�q�已�l�commit的数据。下面是一个小的测试，证明InnoDB的可重复读隔��ȝ�别不�?x��)造成�q�象诅R��测试涉�?qi��ng)两个session�Q�分别�ؓ(f��)session 1和session 2�Q�隔��ȝ�别都是repeateable read�Q�关闭autocommit
mysql> select @@tx_isolation;
+-----------------+
| @@tx_isolation |
+-----------------+
| REPEATABLE-READ |
+-----------------+
1 row in set (0.00 sec)

mysql> set autocommit=off;
Query OK, 0 rows affected (0.00 sec)
session 1 创徏表�ƈ插入��试数据
mysql> create table test(i int) engine=innodb;
Query OK, 0 rows affected (0.00 sec)

mysql> insert into test values(1);
Query OK, 1 row affected (0.00 sec)
session 2 查询�Q�没有数据，正常�Q�session1没有提交�Q�不允许脏读
mysql> select * from test;
Empty set (0.00 sec)
session 1 提交事务
mysql> commit;
Query OK, 0 rows affected (0.00 sec)
session 2 查询�Q�还是没有数据，没有产生�q�象�?/p>
mysql> select * from test;
Empty set (0.00 sec)
以上试验版本�Q?/p>
mysql> select version();
+-------------------------+
| version() |
+-------------------------+
| 5.0.37-community-nt-log |
+-------------------------+
1 row in set (0.00 sec)
--EOF--
作者：(x��)江枫| 【�{载时请务必以��链接�Ş式标明文章原始出处和作者信息及(qi��ng)本声明�?br style="word-break: break-all; line-height: normal !important; " />地址�Q?a title="traceback" rel="trackback" style="word-break: break-all; text-decoration: underline; color: #000066; line-height: normal !important; ">http://rdc.taobao.com/blog/dba/html/91_mysql_innodb_transaction_isolation_level.html

liangcmwn 2011-08-16 09:15 发表评论

Mysql常用操作

liangcmwn — Mon, 15 Aug 2011 08:50:00 GMT

查看MySQL的当前存储引�?/strong>
一般情况下�Q�mysql�?x��)默认提供多�U�存储引�?你可以通过下面的查�?
看你的mysql现在已提供什么存储引�?
mysql> show engines;
看你的mysql当前默认的存储引�?
mysql> show variables like '%storage_engine%';
你要看某个表用了(ji��n)什么引�?在显�C�结果里参数engine后面的就表示该表当前用的存储引擎):
mysql> show create table 表名;

MySQL ��q��的根源是�?MySQL 字符集设�|�不当的问题�Q�本文汇��M��(ji��n)有关查看 MySQL 字符集的命��o(h��)。包括查�?MySQL 数据�?/strong>服务器字�W�集、查�?MySQL 数据库字�W�集�Q�以�?qi��ng)数据表和字�D늚�字符集、当�?a target="_self" style="word-break: break-all; text-decoration: underline; color: #070648; line-height: normal !important; ">安装�?MySQL 所支持的字�W�集�{��?/p>
一、查�?MySQL 数据库服务器和数据库字符集�?/p>
mysql> show variables like '%char%'; +--------------------------+-------------------------------------+------ | Variable_name | Value |...... +--------------------------+-------------------------------------+------ | character_set_client | utf8 |...... -- 客户端字�W�集 | character_set_connection | utf8 |...... | character_set_database | utf8 |...... -- 数据库字�W�集 | character_set_filesystem | binary |...... | character_set_results | utf8 |...... | character_set_server | utf8 |...... -- 服务器字�W�集 | character_set_system | utf8 |...... | character_sets_dir | D:\MySQL Server 5.0\share\charsets\ |...... +--------------------------+-------------------------------------+------
二、查�?MySQL 数据表（table�Q?的字�W�集�?/p>
mysql> show table status from sqlstudy_db like '%countries%'; +-----------+--------+---------+------------+------+-----------------+------ | Name | Engine | Version | Row_format | Rows | Collation |...... +-----------+--------+---------+------------+------+-----------------+------ | countries | InnoDB | 10 | Compact | 11 | utf8_general_ci |...... +-----------+--------+---------+------------+------+-----------------+------
三、查�?MySQL 数据列（column�Q�的字符集�?/p>
mysql> show full columns from countries; +----------------------+-------------+-----------------+-------- | Field | Type | Collation | ....... +----------------------+-------------+-----------------+-------- | countries_id | int(11) | NULL | ....... | countries_name | varchar(64) | utf8_general_ci | ....... | countries_iso_code_2 | char(2) | utf8_general_ci | ....... | countries_iso_code_3 | char(3) | utf8_general_ci | ....... | address_format_id | int(11) | NULL | ....... +----------------------+-------------+-----------------+--------
四、查看当前安装的 MySQL 所支持的字�W�集�?/p>
mysql> show charset; mysql> show char set; +----------+-----------------------------+---------------------+--------+ | Charset | Description | Default collation | Maxlen | +----------+-----------------------------+---------------------+--------+ | big5 | Big5 Traditional Chinese | big5_chinese_ci | 2 | | dec8 | DEC West European | dec8_swedish_ci | 1 | | cp850 | DOS West European | cp850_general_ci | 1 | | hp8 | HP West European | hp8_english_ci | 1 | | koi8r | KOI8-R Relcom Russian | koi8r_general_ci | 1 | | latin1 | cp1252 West European | latin1_swedish_ci | 1 | | latin2 | ISO 8859-2 Central European | latin2_general_ci | 1 | | swe7 | 7bit Swedish | swe7_swedish_ci | 1 | | ascii | US ASCII | ascii_general_ci | 1 | | ujis | EUC-JP Japanese | ujis_japanese_ci | 3 | | sjis | Shift-JIS Japanese | sjis_japanese_ci | 2 | | hebrew | ISO 8859-8 Hebrew | hebrew_general_ci | 1 | | tis620 | TIS620 Thai | tis620_thai_ci | 1 | | euckr | EUC-KR Korean | euckr_korean_ci | 2 | | koi8u | KOI8-U Ukrainian | koi8u_general_ci | 1 | | gb2312 | GB2312 Simplified Chinese | gb2312_chinese_ci | 2 | | greek | ISO 8859-7 Greek | greek_general_ci | 1 | | cp1250 | Windows Central European | cp1250_general_ci | 1 | | gbk | GBK Simplified Chinese | gbk_chinese_ci | 2 | | latin5 | ISO 8859-9 Turkish | latin5_turkish_ci | 1 | | armscii8 | ARMSCII-8 Armenian | armscii8_general_ci | 1 | | utf8 | UTF-8 Unicode | utf8_general_ci | 3 | | ucs2 | UCS-2 Unicode | ucs2_general_ci | 2 | | cp866 | DOS Russian | cp866_general_ci | 1 | | keybcs2 | DOS Kamenicky Czech-Slovak | keybcs2_general_ci | 1 | | macce | Mac Central European | macce_general_ci | 1 | | macroman | Mac West European | macroman_general_ci | 1 | | cp852 | DOS Central European | cp852_general_ci | 1 | | latin7 | ISO 8859-13 Baltic | latin7_general_ci | 1 | | cp1251 | Windows Cyrillic | cp1251_general_ci | 1 | | cp1256 | Windows Arabic | cp1256_general_ci | 1 | | cp1257 | Windows Baltic | cp1257_general_ci | 1 | | binary | Binary pseudo charset | binary | 1 | | geostd8 | GEOSTD8 Georgian | geostd8_general_ci | 1 | | cp932 | SJIS for Windows Japanese | cp932_japanese_ci | 2 | | eucjpms | UJIS for Windows Japanese | eucjpms_japanese_ci | 3 | +----------+-----------------------------+---------------------+--------+
以上查看 MySQL 字符集命令，适用�?Windows & Linux�?/p>

liangcmwn 2011-08-15 16:50 发表评论

mysql中limit用法

liangcmwn — Wed, 27 Jul 2011 09:10:00 GMT

使用查询语句的时候，�l�常要返回前几条或者中间某几行数据�Q�这个时候怎么办呢�Q�不用担心，mysql�?�l��ؓ(f��)我们提供�?ji��n)这样一个功能�?/p>

SELECT * FROM table   LIMIT [offset,] rows | rows OFFSET offset

      LIMIT 子句可以被用于强�?SELECT 语句�q�回指定的记录数。LIMIT 接受一个或两个数字参数。参数必��L��一个整数常量。如果给定两个参敎ͼ��W�一个参数指定第一个返回记录行的偏�U�量�Q�第二个参数指定�q�回记录行的最大数目。初始记录行的偏�U�量�?0(而不�?1)�Q?��Z��(ji��n)�?PostgreSQL 兼容�Q�MySQL 也支持句法：(x��) LIMIT # OFFSET #�?/p>

mysql> SELECT * FROM table LIMIT 5,10;  // ��(g��)索记录行 6-15

//��Z��(ji��n)��(g��)索从某一个偏�U�量到记录集的结束所有的记录行，可以指定�W�二个参��Cؓ(f��) -1�Q?
mysql> SELECT * FROM table LIMIT 95,-1; // ��(g��)索记录行 96-last.

//如果只给定一个参敎ͼ�它表�C��回最大的记录行数目：(x��)
mysql> SELECT * FROM table LIMIT 5;     //��(g��)索前 5 个记录行

//换句话说�Q�LIMIT n �{��h(hu��n)�?LIMIT 0,n�?/span>

实例�Q?/strong>

mysql> use sppeivan;
Database changed
mysql> select * from employee; // �q�回所有结�?/strong>
+------------+------------+--------+-------------+
| username   | password   | gender | cellphone   |
+------------+------------+--------+-------------+
| ewrew      | erewr      | MAN    | 13618889076 |
| ewrwerw32r | 324324     | MAN    | 13618889076 |
| grrrrr     | r44343     | WOMAN | 13618889076 |
| pansong    | erewrwe    | MAN    | 13618889076 |
| ret43t43t | 43t43      | MAN    | 13618889076 |
| ret44t4    | r4tgr      | WOMAN | 13618889076 |
| tttt       | 4et        | WOMAN | 13618889076 |
| wr34r      | retre      | MAN    | 13618889076 |
| xxx     | safe       | MAN    | 13618889076 |
| hhh       | ewrwer     | MAN    | 13618889076 |
| hg       | 6574326543 | MAN    | 13618889076 |
| ps       | ewrwe      | MAN    | 13618889076 |
| zhu       | werew      | MAN    | 13618889076 |
+------------+------------+--------+-------------+
13 rows in set (0.01 sec)

mysql> select * from employee limit 3 7;
ERROR 1064 (42000): You have an error in your SQL syntax
corresponds to your MySQL server version for the right s
line 1
mysql> select * from employee limit 3, 7; // �q�回4-11�?/strong>
+-----------+----------+--------+-------------+
| username | password | gender | cellphone   |
+-----------+----------+--------+-------------+
| pansong   | erewrwe | MAN    | 13618889076 |
| ret43t43t | 43t43    | MAN    | 13618889076 |
| ret44t4   | r4tgr    | WOMAN | 13618889076 |
| tttt      | 4et      | WOMAN | 13618889076 |
| wr34r     | retre    | MAN    | 13618889076 |
| xxx     | safe     | MAN    | 13618889076 |
| hhh      | ewrwer   | MAN    | 13618889076 |
+-----------+----------+--------+-------------+
7 rows in set (0.00 sec)

mysql> select * from employee limit 3,-1; // 错误语法
ERROR 1064 (42000): You have an error in your SQL syntax
corresponds to your MySQL server version for the right s
t line 1

mysql> select * from employee limit 3,1; // �q�回�W?�?/strong>
+----------+----------+--------+-------------+
| username | password | gender | cellphone   |
+----------+----------+--------+-------------+
| pansong | erewrwe | MAN    | 13618889076|
+----------+----------+--------+-------------+
1 row in set (0.00 sec)

mysql> select * from employee limit 3; // �q�回�?�?/strong>

+------------+----------+--------+-------------+
| username   | password | gender | cellphone   |
+------------+----------+--------+-------------+
| ewrew      | erewr    | MAN    | 13618889076 |
| ewrwerw32r | 324324   | MAN    | 13618889076 |
| grrrrr     | r44343   | WOMAN | 13618889076 |
+------------+----------+--------+-------------+
3 rows in set (0.00 sec)

mysql> select * from employee limit 10; // �q�回�?0�?/strong>

+------------+----------+--------+-------------+
| username   | password | gender | cellphone   |
+------------+----------+--------+-------------+
| ewrew      | erewr    | MAN    | 13618889076 |
| ewrwerw32r | 324324   | MAN    | 13618889076 |
| grrrrr     | r44343   | WOMAN | 13618889076 |
| pansong    | erewrwe | MAN    | 13618889076 |
| ret43t43t | 43t43    | MAN    | 13618889076 |
| ret44t4    | r4tgr    | WOMAN | 13618889076 |
| tttt       | 4et      | WOMAN | 13618889076 |
| wr34r      | retre    | MAN    | 13618889076 |
| xxx     | safe     | MAN    | 13811588469 |
| hhh       | ewrwer   | MAN    | 13618889076 |
+------------+----------+--------+-------------+
10 rows in set (0.00 sec)

mysql> select * from employee limit 9,1; // �q�回�W?0�?/strong>

+----------+----------+--------+-------------+
| username | password | gender | cellphone   |
+----------+----------+--------+-------------+
| hhh     | ewrwer   | MAN    | 13816668468 |
+----------+----------+--------+-------------+
1 row in set (0.00 sec)

liangcmwn 2011-07-27 17:10 发表评论