- 先执行flush tables关闭所有打开的表
- 上全局读锁FTWRL
- 设置会话的隔离级别为RR
- 开启一致性快照事务
- 获取master status 已经执行事务信息
- 获取备份表信息
- select from table dump出数据
FLUSH TABLES
force it to flush any table modifications that are still buffered in memory Closes all open tables;
forces all tables in use to be closed, and flushes the prepared statement cache
--single-transaction 开启一致性备份
--default-parallelism 并行备份线程数
--parallel-schemas=[N:]db_list 可对不同的库指定不同的并行备份线程数
mysqlpump默认备份会设置备份文件的字符集为utf8mb4（SET NAMES utf8mb4），设置--default-character-set可指定备份文件的字符集
mysqlpump的并行备份是基于不同的表的（即时指定了并行备份，对同一张表也只会有一个线程备份）
有多少个并发线程备份，就会建立多少个子线程开启RR隔离级别一致性快照
设置了并行备份时，第一个线程会执行FTWRL，再开启RR隔离级别一致性快照；等其它线程都开启了一致性快照后再 unlock tables 取消全局读锁（确保并行备份每个线程得到一致的数据）
已经指定了对指定的表进行备份，还会show 其它表的status和其它对象（trigger,event的status），show create table 其它表，和备份整个实例一样
表数量多时，会花费更多的时间；在备份文件中却只有指定的表信息
备份文件中最后才添加二级索引 ALTER TABLE test.sbtest1 ADD KEY k_1 (k); 加快了导入的速度（减少导入时了维护二级索引的开销）
2019-03-25T21:11:15.524978+08:00 429 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.549169+08:00 429 Query FLUSH TABLES WITH READ LOCK
2019-03-25T21:11:15.549937+08:00 429 Query SHOW WARNINGS
2019-03-25T21:11:15.551858+08:00 429 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.551958+08:00 429 Query SHOW WARNINGS
2019-03-25T21:11:15.552031+08:00 429 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.552106+08:00 429 Query SHOW WARNINGS
2019-03-25T21:11:15.552337+08:00 430 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.552453+08:00 430 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.552532+08:00 430 Query SHOW WARNINGS
2019-03-25T21:11:15.552597+08:00 430 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.552663+08:00 430 Query SHOW WARNINGS
2019-03-25T21:11:15.552869+08:00 431 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.553070+08:00 431 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.553215+08:00 431 Query SHOW WARNINGS
2019-03-25T21:11:15.553330+08:00 431 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.553432+08:00 431 Query SHOW WARNINGS
2019-03-25T21:11:15.553714+08:00 432 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.553833+08:00 432 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.553905+08:00 432 Query SHOW WARNINGS
2019-03-25T21:11:15.553986+08:00 432 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.554048+08:00 432 Query SHOW WARNINGS
2019-03-25T21:11:15.554349+08:00 433 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.554485+08:00 433 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.554563+08:00 433 Query SHOW WARNINGS
2019-03-25T21:11:15.554635+08:00 433 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.554698+08:00 433 Query SHOW WARNINGS
2019-03-25T21:11:15.554933+08:00 434 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.555058+08:00 434 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.555175+08:00 434 Query SHOW WARNINGS
2019-03-25T21:11:15.555243+08:00 434 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.555301+08:00 434 Query SHOW WARNINGS
2019-03-25T21:11:15.555510+08:00 435 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.555702+08:00 435 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.555835+08:00 435 Query SHOW WARNINGS
2019-03-25T21:11:15.555963+08:00 435 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.556083+08:00 435 Query SHOW WARNINGS
2019-03-25T21:11:15.556360+08:00 436 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.556486+08:00 436 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.556563+08:00 436 Query SHOW WARNINGS
2019-03-25T21:11:15.556628+08:00 436 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.556689+08:00 436 Query SHOW WARNINGS
2019-03-25T21:11:15.558260+08:00 437 Connect test1@127.0.0.1 on using TCP/IP
2019-03-25T21:11:15.558487+08:00 437 Query SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ
2019-03-25T21:11:15.558647+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:15.558768+08:00 437 Query START TRANSACTION WITH CONSISTENT SNAPSHOT
2019-03-25T21:11:15.558878+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:15.559015+08:00 429 Query UNLOCK TABLES
2019-03-25T21:11:15.559141+08:00 429 Query SHOW WARNINGS
2019-03-25T21:11:15.559244+08:00 437 Query SET SQL_QUOTE_SHOW_CREATE= 1
2019-03-25T21:11:15.559370+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:15.559474+08:00 437 Query SET TIME_ZONE='+00:00'
2019-03-25T21:11:15.559578+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:15.559682+08:00 437 Query SELECT @@global.gtid_mode
2019-03-25T21:11:15.559794+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:15.559871+08:00 437 Query SELECT @@GLOBAL.GTID_EXECUTED
2019-03-25T21:11:15.559993+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:15.560311+08:00 437 Query SHOW DATABASES
2019-03-25T21:11:15.645400+08:00 436 Query SET SQL_QUOTE_SHOW_CREATE= 1
2019-03-25T21:11:15.645632+08:00 436 Query SHOW WARNINGS
2019-03-25T21:11:15.645744+08:00 436 Query SET TIME_ZONE='+00:00'
2019-03-25T21:11:15.645819+08:00 436 Query SHOW WARNINGS
2019-03-25T21:11:16.473856+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:16.474118+08:00 437 Query SHOW CREATE DATABASE IF NOT EXISTS information_schema
2019-03-25T21:11:16.474206+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:16.474315+08:00 437 Query SHOW TABLE STATUS FROM information_schema
2019-03-25T21:11:16.501656+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:16.501933+08:00 437 Query SHOW COLUMNS IN CHARACTER_SETS FROM information_schema
2019-03-25T21:11:16.502417+08:00 437 Query SHOW WARNINGS
2019-03-25T21:11:16.502531+08:00 437 Query SHOW CREATE TABLE information_schema.CHARACTER_SETS
..........
mydumper默认会开启一致性快照备份
有多少个并发线程备份，就会建立多少个子线程+1（第一个线程加FTWRL和开启一致性快照）