Mysql mysqldump备份数据库

mysqldump备份数据库

背景

• 数据库在测试环境，不是很稳定，存在丢失的风险
• 数据库表结构变化较频繁，存在业务系统产生的测试数据，过程繁琐不能伪造
• 有些数据，比如日志流水，备份时需要先删除老数据，只保留部分最近的日志即可

因此直接使用crontab每天定时备份数据库，同时做一些清理。

mysqldump 语法

Dumping structure and contents of MySQL databases and tables.
Usage: mysqldump [OPTIONS] database [tables]
OR     mysqldump [OPTIONS] --databases [OPTIONS] DB1 [DB2 DB3...]
OR     mysqldump [OPTIONS] --all-databases [OPTIONS]

参数说明：MySQL mysqldump数据导出详解

备份脚本

#!/bin/bash

# base dir
BASE_DIR=/any/path
# mysql common params
MYSQL_COMMON_PARAMS="-h192.168.0.192 -uroot -proot"
# date
DATE=`date "+%Y-%m-%d"`
echo "[`date`] database scheduler back up start $DATE --------------------" >> $BASE_DIR/back.log

# back up start
mysqldump $MYSQL_COMMON_PARAMS --databases scheduler | gzip > $BASE_DIR/data/scheduler_$DATE.sql.gz

# delete old back up data
# delete file 10 days ago
find $BASE_DIR/data -mtime +10  -name "*.gz" -exec rm -rf {} \;

# delete old data from scheduler.qrtz_log
# too much unuseful log
echo "DELETE FROM qrtz_log WHERE CREATE_TIME < '$DATE';" > $BASE_DIR/delete_qrtz_log.sql
echo "[`date`] DELETE FROM qrtz_log WHERE CREATE_TIME < '$DATE';" >> $BASE_DIR/back.log

# execute sql from file
mysql $MYSQL_COMMON_PARAMS -DScheduler < $BASE_DIR/delete_qrtz_log.sql
echo "[`date`] database scheduler back up end $DATE --------------------" >> $BASE_DIR/back.log

crontab

0 2 * * * sh /any/path/back.sh >> /any/path/back.log

导入

• 可以直接在mysql控制台用source命令导入

[root]# mysql
MySQL > source backupfile.sql

• 也可以直接用命令

# for sql
mysql -hhostname -uusername -ppassword [databasename] < backupfile.sql

#for gzip
gunzip < backupfile.sql.gz | mysql -uusername -ppassword [databasename]

其他备份方法

当需要根据where条件导出时，一种办法是使用--databases db1 --tables tb1 tb2 --where 'col_name=col_value'，但是这种办法只能导出一个表或者导出多个表中相同条件的数据，如果条件比较复杂或者需要连表查询，可能不太方便，如果在--where条件里面这样写--where 'CREATE_TIME>(select max(CREATE_TIME) from t1)'会报错Table 't1' was not locked with LOCK TABLES (1100)，这时候可以用select into outfile和load data local infile into table来操作。

[root]# mysql
MySQL [(none)] > use test;
Database changed
MySQL [test]> SELECT @@global.secure_file_priv;
+---------------------------+
| @@global.secure_file_priv |
+---------------------------+
| /var/lib/mysql-files/     |
+---------------------------+
1 row in set (0.00 sec)
# 上面这个路径是select into 和 load into文件存放的位置，可以在my.ini修改
# 如果导入导出的文件不在这个目录下，会报下面的错
# [Err] 1290 - The MySQL server is running with the --secure-file-priv option so it cannot execute this statement

MySQL [(test)] > SELECT t1.* FROM t1 WHERE col2 IN (SELECT col1 FROM t2) INTO OUTFILE '/var/lib/mysql-files/test.sql';
Query OK, 2 rows affected (0.00 sec)

MySQL [(test)] > DELETE FROM t1;
Query OK, 2 rows affected (0.00 sec)

MySQL [(test)] > LOAD DATA INFILE '/var/lib/mysql-files/test.sql' INTO TABLE t1;
Query OK, 2 rows affected (0.00 sec)
Records: 2  Deleted: 0  Skipped: 0  Warnings: 0