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0、前言

1、mysqldump

mysqldump 几个主要选项
1. -q
很简单，什么都不做，只是导出时加了一个 SQL_NO_CACHE 来确保不会读取缓存里的数据。

081022 17:39:33       7 Connect     root@localhost on
7 Query       /*!40100 SET @@SQL_MODE='' */
7 Init DB     yejr
7 Query       SHOW TABLES LIKE 'yejr'
7 Query       LOCK TABLES `yejr` READ /*!32311 LOCAL */
7 Query       SET OPTION SQL_QUOTE_SHOW_CREATE=1
7 Query       show create table `yejr`
7 Query       show fields from `yejr`
7 Query       show table status like 'yejr'
7 Query       SELECT /*!40001 SQL_NO_CACHE */ * FROM `yejr`
7 Query       UNLOCK TABLES
7 Quit

081022 17:36:21       5 Connect     root@localhost on
5 Query       /*!40100 SET @@SQL_MODE='' */
5 Init DB     yejr
5 Query       SHOW TABLES LIKE 'yejr'
5 Query       LOCK TABLES `yejr` READ /*!32311 LOCAL */
5 Query       SET OPTION SQL_QUOTE_SHOW_CREATE=1
5 Query       show create table `yejr`
5 Query       show fields from `yejr`
5 Query       show table status like 'yejr'
5 Query       SELECT /*!40001 SQL_NO_CACHE */ * FROM `yejr`
5 Query       UNLOCK TABLES
5 Quit

081022 17:36:55       6 Connect     root@localhost on
6 Query       /*!40100 SET @@SQL_MODE='' */
6 Query       FLUSH TABLES
6 Query       FLUSH TABLES WITH READ LOCK
6 Init DB     yejr
6 Query       SHOW TABLES LIKE 'yejr'
6 Query       SET OPTION SQL_QUOTE_SHOW_CREATE=1
6 Query       show create table `yejr`
6 Query       show fields from `yejr`
6 Query       show table status like 'yejr'
6 Query       SELECT /*!40001 SQL_NO_CACHE */ * FROM `yejr`
6 Quit

081022 17:59:02       1 Connect     root@localhost on
1 Query       /*!40100 SET @@SQL_MODE='' */
1 Query       FLUSH TABLES
1 Query       FLUSH TABLES WITH READ LOCK
1 Query       SHOW MASTER STATUS
1 Init DB     yejr
1 Query       SHOW TABLES LIKE 'yejr'
1 Query       SET OPTION SQL_QUOTE_SHOW_CREATE=1
1 Query       show create table `yejr`
1 Query       show fields from `yejr`
1 Query       show table status like 'yejr'
1 Query       SELECT /*!40001 SQL_NO_CACHE */ * FROM `yejr`
1 Quit

081022 17:23:35       1 Connect     root@localhost on
1 Query       /*!40100 SET @@SQL_MODE='' */
1 Query       SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
1 Query       BEGIN
1 Query       UNLOCK TABLES
1 Init DB     yejr
1 Query       SHOW TABLES LIKE 'yejr'
1 Query       SET OPTION SQL_QUOTE_SHOW_CREATE=1
1 Query       show create table `yejr`
1 Query       show fields from `yejr`
1 Query       show table status like 'yejr'
1 Query       SELECT /*!40001 SQL_NO_CACHE */ * FROM `yejr`
1 Quit

081022 17:27:07       2 Connect     root@localhost on
2 Query       /*!40100 SET @@SQL_MODE='' */
2 Query       FLUSH TABLES
2 Query       FLUSH TABLES WITH READ LOCK
2 Query       SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2 Query       START TRANSACTION WITH CONSISTENT SNAPSHOT
2 Query       SHOW MASTER STATUS
2 Query       UNLOCK TABLES
2 Init DB     yejr
2 Query       SHOW TABLES LIKE 'yejr'
2 Query       SET OPTION SQL_QUOTE_SHOW_CREATE=1
2 Query       show create table `yejr`
2 Query       show fields from `yejr`
2 Query       show table status like 'yejr'
2 Query       SELECT /*!40001 SQL_NO_CACHE */ * FROM `yejr`
2 Quit

The WITH CONSISTENT SNAPSHOT clause starts a consistent read for storage engines that are capable of it. This applies only to InnoDB. The effect is the same as issuing a START TRANSACTION followed by a SELECT from any InnoDB  table. See Section 13.2.10.4, “Consistent Non-Locking Read”. The WITH CONSISTENT SNAPSHOT clause does not change the current transaction isolation level, so it provides a consistent snapshot only if the current isolation level is one that allows consistent read (REPEATABLE READ or SERIALIZABLE).

2. mysqldump 和 mk-parralel-dump 的比较

2.1 mysqldump 常规使用

#导出耗时
time mysqldump -f --single-transaction -B yejr --tables yejr | gzip > /home/databak/yejr.sql.gz
real    10m15.319s
user    6m47.946s
sys     0m38.496s
#文件大小
608M /home/databak/yejr.sql.gz
#导出期间系统负载
05:00:01 PM       all      0.71      0.00      0.61      7.33     91.36
05:10:02 PM       all     13.93      0.00      2.21      4.64     79.22

2.2 mysqldump + gzip --fast

#导出耗时
time mysqldump -f --single-transaction -B yejr --tables yejr | gzip --fast > /home/databak/yejr_fast.sql.gz
real    9m6.248s
user    4m21.467s
sys     0m37.604s
#文件大小
815M Oct 21 17:33 /home/databak/yejr_fast.sql.gz
#导出期间系统负载
05:20:01 PM       all     11.94      0.00      2.43      5.69     79.94
05:30:01 PM       all      6.46      0.00      1.57      3.95     88.02

2.3 mk-parallel-dump 常规使用

time ./mk-parallel-dump --database yejr --tables yejr --basedir /home/databak/
default:             25 tables,    25 chunks,    25 successes,  0 failures, 404.93 wall-clock time, 613.25 dump time
real    6m48.763s
user    4m20.724s
sys     0m38.125s
#文件大小
819M    /home/databak/default/yejr/
#导出期间系统负载
05:10:02 PM       all     13.93      0.00      2.21      4.64     79.22
05:20:01 PM       all     11.94      0.00      2.43      5.69     79.94