11 KiB
11 KiB
title, date, lastmod, tags, categories
| title | date | lastmod | tags | categories | ||
|---|---|---|---|---|---|---|
| Mysql 笔记 | 2019-10-30T11:51:23+08:00 | 2019-10-30T11:51:23+08:00 |
|
|
MySQL 5.7 配置文件 my.cnf
[mysqld]
datadir = /db/mysql
socket = /var/lib/mysql/mysql.sock
symbolic-links = 0
log-timestamps = SYSTEM
slow-query-log = 1
slow-query-log-file = /var/log/mysqld/slow.log
long-query-time = 8
#log-queries-not-using-indexes = 1
log-error = /var/log/mysqld/error.log
pid-file = /var/run/mysqld/mysqld.pid
max-connections = 1000
max-connect-errors = 1000
max-user-connections = 600
interactive-timeout = 3600
wait-timeout = 3600
skip-name-resolve = 1
lower-case-table-names = 1
default-time-zone = '+08:00'
character-set-server = utf8mb4
sql-mode = NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES
bind-address = 0.0.0.0
table-open-cache = 2048
default-storage-engine = innodb
innodb-autoinc-lock-mode = 2
innodb-flush-log-at-trx-commit = 0
# 建议物理内存一半
innodb-buffer-pool-size = 8G
innodb-buffer-pool-instances = 8
max-allowed-packet = 512M
query-cache-size = 0
query-cache-type = 0
# 建议点分 ip 的最后一个数字
server-id = 123
# bin log
#binlog-format = ROW
#log-bin = /var/lib/mysql/mysql-bin
#expire-logs-days = 3
# relay log
#read-only = 1
#replicate-wild-do-table = db1.%
#relay-log = /var/lib/mysql/mysql-relay-bin
#slave-parallel-type = logical-clock
复制表结构
create table db1.t1 like db2.t2;
create table db1.t1 select db2.t2 where 1=2;
复制表结构及其数据
create table db1.t1 select db2.t2 [where ...]
复制表数据
insert into db2.t2(column1, column2 ...)
select column1, column2 ... from db1.t1 [where ...]
通过复制表文件来复制表数据
-
在db2中创建同结构表
create table db2.t1 like db1.t1; -
丢弃表空间
alter table db2.t1 discard tablespace; -
复制 t1 的表数据文件
#关闭数据库 systemctl stop mysqld cd /var/lib/mysql scp db1/t1.idb db2/t1.idb chown mysql.mysql db2/t1.idb #启动数据库 systemctl start mysqld -
导入表空间
alter table db2.t1 import tablespace;
设置一个表的空列自增
-- 删除可能存在的主键
alter table 表名 drop primary key;
alter table 表名 modify 列名 auto_increment primary key;
查看数据库中每个表的全部列名
select table_name, column_name from
information_schema.columns
where table_schema = '数据库名';
查看数据库中每个表的行数
select table_name, table_rows
from information_schema.tables
where table_schema = '数据库名';
查看数据库中每个表的索引
select table_name, column_name, index_name
from INFORMATION_SCHEMA.STATISTICS
where table_schema = '数据库名';
表的部分列数据到另一个表
update db2.t2(column1, column2 ...) = (
select column1, column2 from db1.t1
where db1.t1.id = db2.t2.id);
把语句执行结果写到文件
mysql -uroot -p -hsever_ip -Ddb_name
-Ne "select ... from table_name;" > file_name
表分区
-
查看表的分区情况
select table_schema, table_name, partition_name, table_rows from information_schema.partitions where table_name = 'table_name'; -
建表时指定
create table table_name(...) partition by range columns(column_name) (partition part_name values less than(some_value)); -
修改成分区表
alter table table_name partition by range(column_name) (partition part_name values less than(som_value)); -
增加分区
alter table table_name add partition (partition part_name values less than(som_value)); -
删除分区
alter table table_name drop partition part_name; -
合并/拆分分区
alter table table_name reorganize part_old_1, part_old_2, part_old_3 into (partition part_new_1 values less than(value_1), partition part_new_2 values less than(value_2)); -
重建分区，整理分区碎片
alter table table_name rebuild partition part_name_1, part_name_2; -
优化分区，回收空间，整理碎片
alter table table_name optimize partition part_name_1, part_name_2; -
分析分区，读取并保存分区的健分布
alter table table_name analyze partition part_name_1, part_name_2; -
修复分区
alter table table_name repair partition part_name_1, part_name_2; -
检查分区
alter table table_name check partition part_name_1, part_name_2;
MySQL 5.7 从库多线程同步
stop slave;
set global slave_parallel_type='logical_clock';
set global slave_parallel_workers=4;
start slave;
show processlist;
MySQL 5.7 提示密码复杂度不够
set global validate_password_policy=0;
MySQL 5.7 从库复制失败跳过指定数量的事务
stop slave;
-- 跳过一个事务
SET GLOBAL SQL_SLAVE_SKIP_COUNTER = 1;
start slave;
-- 修改 my.cnf
slave-skip-errors=1062,1053,1146,1032 #跳过指定error no类型的错误
slave-skip-errors=all #跳过所有错误
MySQL 5.7 查看全部任务
-- 分号换成 \G 显示完整 sql
show processlist;
show full processlist;
SELECT command FROM information_schema.processlist;
MySQL 5.7 ssl 连接
--ssl-mode=REQUIRED
MariaDB 10.1 修改密码
UPDATE user SET password=password('newpassword') WHERE user='root';
MySQL 5.7 编码
-
查看
SHOW VARIABLES LIKE 'character_set%'; -
数据库连接参数中，characterEncoding=utf8 会被自动识别为 utf8mb4，但是 autoReconnect=true 必须指定
-
更改数据库编码
ALTER DATABASE db_name CHARSET UTF8MB4 COLLATE UTF8MB4_GENERAL_CI; -
更改表编码
ALTER TABLE table_name CONVERT TO CHARSET UTF8MB4 COLLATE UTF8MB4_GENERAL_CI;
MySQL 5.7 升级数据库管理表结构
mysql_upgrade -u root -p
MySQL 5.7 误删 root 后恢复 root 账户
-
停止 mysql 服务
systemctl stop mysqld -
修改 my.cnf
# 添加如下一行 skip-grant-tables -
启动 mysql 服务
systemctl start mysqld -
重建 root 账户，并授权
insert into user set user='root', ssl_cipher='', x509_issuer='', x509_subject=''; update user set Host='localhost', select_priv='y', insert_priv='y', update_priv='y', Alter_priv='y', delete_priv='y', create_priv='y', drop_priv='y', reload_priv='y', shutdown_priv='y', Process_priv='y', file_priv='y', grant_priv='y', References_priv='y', index_priv='y', create_user_priv='y', show_db_priv='y', super_priv='y', create_tmp_table_priv='y', Lock_tables_priv='y', execute_priv='y', repl_slave_priv='y', repl_client_priv='y', create_view_priv='y', show_view_priv='y', create_routine_priv='y', alter_routine_priv='y', create_user_priv='y', event_priv='y', trigger_priv='y', create_tablespace_priv='y' where user='root'; flush privileges; -
停止 mysql 服务
systemctl stop mysqld -
修改 my.cnf
# 删除或注释刚添加的如下一行 skip-grant-tables -
启动 mysql 服务，root 账户正常可用
systemctl start mysqld
通过EXPLAIN分析SQL的执行计划
-
使用
explain sql -
select_type 查询类型
- SIMPLE 简单表，没有表连接或子查询
- PRIMARY 最外层的查询
- UNION union语句的后置查询
- SUBQUERY 第一个子查询
-
table 表/别名
-
type 访问类型
- ALL 全表扫描
- index 全索引扫描
- range 索引范围扫描
- ref 非唯一索引扫描
- eq_ref 唯一索引扫描
- const,system 单表最多一个匹配行
- NULL 不需要扫描表或索引
-
possible_keys 查询可能使用的索引
-
key 实际使用的索引
-
key_len 使用的索引字段的长度
-
ref 其他匹配字段
-
rows 扫描行的数量
-
filtered 满足查询条件的记录占存储引擎返回记录的比例
-
Extra 执行情况说明
- Using Index 全部使用索引，没有回表查询
- Using Where 有回表查询
- Using Index Condition ICP优化，直接在存储引擎完成条件过滤
- Using Flesort 依靠索引顺序达不到排序效果，需额外排序
统计 insert、delete、update 和 select 次数
show global status where Variable_name in
('com_insert', 'com_delete', 'com_update', 'com_select');
csv 文件
-
导出
# Shell 终端 # mysql -e "select * from t1 into outfile '/var/lib/mysql-files/t1.csv' fields terminated by ',' enclosed by '\"' escaped by '\\\' lines terminated by '\n'" # MySQL 终端 # MySQL> select * from t1 into outfile '/var/lib/mysql-files/t1.csv' fields terminated by ',' enclosed by '\"' escaped by '\\' lines terminated by '\n'; -
导入
# Shell 终端 # mysql -e "load data infile '/var/lib/mysql-files/t1.csv' into table t1 fields terminated by ',' enclosed by '\"' escaped by '\\\' lines terminated by '\n'" # MySQL 终端 # MySQL> load data infile '/var/lib/mysql-files/t1.csv' into table t1 fields terminated by ',' enclosed by '\"' escaped by '\\' lines terminated by '\n';
mysql8 配置登录失败 5 次锁定 5 分钟
-
安装插件
docker exec -ti mysql mysql -e " install plugin CONNECTION_CONTROL soname 'connection_control.so'; install plugin CONNECTION_CONTROL_FAILED_LOGIN_ATTEMPTS soname 'connection_control.so'; " -
查看插件列表
docker exec -ti mysql mysql -e "show plugins" # 此时会看到最后两行时新激活的插件 -
修改 my.cnf，增加两行
connection-control-failed-connections-threshold=5 connection-control-min-connection-delay=300000 -
重启 mysql