时间：2021-07-01 10:21:17 帮助过：36人阅读
show variables like "concurrent_insert";
+-------------------+-------+
| Variable_name | Value |
+-------------------+-------+
| concurrent_insert | AUTO |
+-------------------+-------+
set GLOBAL concurrent_insert=2;
插入数据时MySQL会对插入的记录进行唯一性校验
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：
SET UNIQUE_CHECKS=0;
重新开启唯一性检查的语句如下：
SET UNIQUE_CHECKS=1;
mysql> show variables like "UNIQUE_CHECKS";
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| unique_checks | ON |
+---------------+-------+
mysql设置最大连接数量
mysql> set GLOBAL max_connections = 1000;
Query OK, 0 rows affected (0.00 sec)
之前配置了mysql的主从备份
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
进入mysql的存储区域，查看一下数据部分的空间大小
/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
显示mysql中数据部分和基本的配置部分所占用的磁盘空间
/mnt/ssd/data$ sudo du -h -d 1
163G ./StockData
636K ./performance_schema
1.7M ./mysql
56K ./db_user_msg
242G .
结果发现这其中很多的空间都被mysql-bin*文件所占用了
/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
现在我们要将这些日志清理掉
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)
如何删除多余的日志
日志的删除
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: 先去获得mysql中数据存储的位置：
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
再去查看master中日志的存储位置：
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)
查询slave节点的更新状态：
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
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；
Mysql>reset master;
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;
Mysql>purge master logs to 'mysql-bin.000215';
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
Mysql>purge master logs before ‘2010-05-22 01:00:00’;
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。
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)