MySql常用命令--优化参数以及日常管理_MySQL
显示插入查询的优化参数：
<code class="hljs asciidoc">show variables like "concurrent_insert"; +-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | concurrent_insert | AUTO | +-------------------+-------+ set GLOBAL concurrent_insert=2;</code>
插入数据时MySQL会对插入的记录进行唯一性校验<br />
这种校验也会降低插入记录的速度。可以在插入记录之前禁用唯一性检查。等到记录插入完毕后再开启。禁用唯一性检查的语句如下：
<code class="hljs asciidoc"><code class="hljs sql">SET UNIQUE_CHECKS=0;</code></code>
<code class="hljs sql">重新开启唯一性检查的语句如下：
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql">SET UNIQUE_CHECKS=1;</code></code></code>
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc">mysql> show variables like "UNIQUE_CHECKS"; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | unique_checks | ON | +---------------+-------+</code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc">mysql设置最大连接数量
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso">mysql> set GLOBAL max_connections = 1000; Query OK, 0 rows affected (0.00 sec)</code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso">之前配置了mysql的主从备份<br />
结果发现日志很多，占据了很多的磁盘空间，需要进行额外的磁盘管理<br />
进入mysql的存储区域，查看一下数据部分的空间大小
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso">/mnt/ssd/data$ ls auto.cnf mysql-bin.000139 mysql-bin.000149 mysql-bin.000159 mysql-bin.000169 mysql-bin.000179 mysql-bin.000189 mysql-bin.000199 mysql-bin.000209 mysql-bin.index db_user_msg mysql-bin.000140 mysql-bin.000150 mysql-bin.000160 mysql-bin.000170 mysql-bin.000180 mysql-bin.000190 mysql-bin.000200 mysql-bin.000210 performance_schema ibdata1 mysql-bin.000141 mysql-bin.000151 mysql-bin.000161 mysql-bin.000171 mysql-bin.000181 mysql-bin.000191 mysql-bin.000201 mysql-bin.000211 StockData ib_logfile0 mysql-bin.000142 mysql-bin.000152 mysql-bin.000162 mysql-bin.000172 mysql-bin.000182 mysql-bin.000192 mysql-bin.000202 mysql-bin.000212 ib_logfile1 mysql-bin.000143 mysql-bin.000153 mysql-bin.000163 mysql-bin.000173 mysql-bin.000183 mysql-bin.000193 mysql-bin.000203 mysql-bin.000213 mysql mysql-bin.000144 mysql-bin.000154 mysql-bin.000164 mysql-bin.000174 mysql-bin.000184 mysql-bin.000194 mysql-bin.000204 mysql-bin.000214 mysql-bin.000135 mysql-bin.000145 mysql-bin.000155 mysql-bin.000165 mysql-bin.000175 mysql-bin.000185 mysql-bin.000195 mysql-bin.000205 mysql-bin.000215 mysql-bin.000136 mysql-bin.000146 mysql-bin.000156 mysql-bin.000166 mysql-bin.000176 mysql-bin.000186 mysql-bin.000196 mysql-bin.000206 mysql-bin.000216 mysql-bin.000137 mysql-bin.000147 mysql-bin.000157 mysql-bin.000167 mysql-bin.000177 mysql-bin.000187 mysql-bin.000197 mysql-bin.000207 mysql-bin.000217 mysql-bin.000138 mysql-bin.000148 mysql-bin.000158 mysql-bin.000168 mysql-bin.000178 mysql-bin.000188 mysql-bin.000198 mysql-bin.000208 mysql-bin.000218</code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso">显示mysql中数据部分和基本的配置部分所占用的磁盘空间
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso">/mnt/ssd/data$ sudo du -h -d 1 163G ./StockData 636K ./performance_schema 1.7M ./mysql 56K ./db_user_msg 242G .</code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso">结果发现这其中很多的空间都被mysql-bin*文件所占用了
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso">/mnt/ssd/data$ sudo du -c -h mysql-bin* 1.1G mysql-bin.000135 ...... 491M mysql-bin.000218 4.0K mysql-bin.index 80G total 结果显示mysql-bin占用了大约80G的磁盘空间</code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso">现在我们要将这些日志清理掉
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc">mysql> show master logs; +------------------+------------+ | Log_name | File_size | +------------------+------------+ | mysql-bin.000135 | 1073742116 | | mysql-bin.000136 | 1073742153 | ...... | mysql-bin.000216 | 1073747783 | | mysql-bin.000217 | 1073742128 | | mysql-bin.000218 | 514734902 | +------------------+------------+ 84 rows in set (0.01 sec) 这应该是主从备份一周以内的日志文件 查看一下目前正在起作用的日志文件是哪一个 mysql> show master status; +------------------+-----------+--------------+------------------+-------------------+ | File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set | +------------------+-----------+--------------+------------------+-------------------+ | mysql-bin.000218 | 514734902 | | | | +------------------+-----------+--------------+------------------+-------------------+ 1 row in set (0.00 sec)</code></code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc">如何删除多余的日志<br />
日志的删除<br />
对于比较繁忙的OLTP系统，由于每天生产日志量大，这些日志如果长时间不清理，将会对磁盘空间带来很大的浪费，因此，定期删除日志是DBA维护Mysql数据库的一个重要工作内容，下面将介绍几种删除日志的常见方法:
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc">先去获得mysql中数据存储的位置：
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc">mysql> show variables like "datadir"; +---------------+-----------------+ | Variable_name | Value | +---------------+-----------------+ | datadir | /var/lib/mysql/ | +---------------+-----------------+ 1 row in set (0.00 sec) 这是mysql中的默认存储位置</code></code></code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc">再去查看master中日志的存储位置：
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk">mysql> show variables like "log%"; +----------------------------------------+-------------------------------+ | Variable_name | Value | +----------------------------------------+-------------------------------+ | log_bin | ON | | log_bin_basename | /mnt/ssd/data/mysql-bin | | log_bin_index | /mnt/ssd/data/mysql-bin.index | | log_bin_trust_function_creators | OFF | | log_bin_use_v1_row_events | OFF | | log_error | /var/log/mysql/error.log | | log_output | FILE | | log_queries_not_using_indexes | OFF | | log_slave_updates | OFF | | log_slow_admin_statements | OFF | | log_slow_slave_statements | OFF | | log_throttle_queries_not_using_indexes | 0 | | log_warnings | 1 | +----------------------------------------+-------------------------------+ 13 rows in set (0.00 sec)</code></code></code></code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk">查询slave节点的更新状态：
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso">mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 25.25.2.6
Master_User: gpx_sync
Master_Port: 3306
Connect_Retry: 10
Master_Log_File: mysql-bin.000218
Read_Master_Log_Pos: 514734902
Relay_Log_File: mysqld-relay-bin.000669
Relay_Log_Pos: 236
Relay_Master_Log_File: mysql-bin.000218
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table: StockData.t_day_stock
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 514734902
Relay_Log_Space: 132818854
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: e61e54d8-1e08-11e5-9160-44a842112d25
Master_Info_File: /var/lib/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
1 row in set (0.00 sec)
这里面我们获得的有用的信息是：
Master_Log_File: mysql-bin.000218
Read_Master_Log_Pos: 514734902
Relay_Log_File: mysqld-relay-bin.000669
Relay_Log_Pos: 236
Relay_Master_Log_File: mysql-bin.000218
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it</code></code></code></code></code></code></code></code></code></code></code></code><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso">执行“reset master;”命令，该命令将删除所有二进制日志，新日志的编号从“000001” 开始；
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl">Mysql>reset master;</code></code></code></code></code></code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl">执行“Purge master logs to ‘mysql-bin.’” 命令，该命令将删除“” 编号之前的所有日志，下列中删除了“mysql-bin.000001”之前编号的所有日志;
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl"><code class="hljs vbnet">Mysql>purge master logs to 'mysql-bin.000215';</code></code></code></code></code></code></code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl"><code class="hljs vbnet">执行“purge master logs before ‘yyyy-mm-dd hh24:min:ss’”命令，该命令将删除日期为“yyyy-mm-dd hh24:mi:ss”之前产生的所有日志，下列中删除了日期在“2010-05-22 01:00:00”之前的所有日志
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl"><code class="hljs vbnet"><code class="hljs css">Mysql>purge master logs before ‘2010-05-22 01:00:00’;</code></code></code></code></code></code></code></code></code></code></code></code></code></code></code>
<code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl"><code class="hljs vbnet"><code class="hljs css">设置参数 –expire_logs_days=#(days)，此参数的含义是设置日志的过期天数，过来指定的天数后日志将会被自动删除，这样将有利于减少DBA管理日志的工作量。
<code class="hljs asciidoc"><code class="hljs sql"><code class="hljs sql"><code class="hljs asciidoc"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs lasso"><code class="hljs asciidoc"><code class="hljs asciidoc"><code class="hljs smalltalk"><code class="hljs lasso"><code class="hljs perl"><code class="hljs vbnet"><code class="hljs css"><code class="hljs asciidoc">gpx@dell:~$ sudo vim /etc/mysql/my.cnf [mysqld] expire_logs_days = 3 这样，3天前的日志都会被删除，系统自动删除 查看系统中对于二进制日志自动删除的过期时间 mysql> show variables like "expire%"; +------------------+-------+ | Variable_name | Value | +------------------+-------+ | expire_logs_days | 3 | +------------------+-------+ 1 row in set (0.00 sec)</code></code></code></code></code></code></code></code></code></code></code></code></code></code></code></code>
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