用来测试新老版本数据库对sql的结果是否一致。
两台开发测试数据库，一台是老版本，一台是新版本，来做比较，生产库别用。
pt-upgrade h=192.168.100.101,P=3306,u=admin,p=admin h=192.168.100.103,P=3306,u=admin,p=admin --database db01 pt-upgrade.sql
cat pt-upgrade.sql
select * from t01 where code>1;
#-----------------------------------------------------------------------
# Logs
#-----------------------------------------------------------------------
File: pt-upgrade.sql
Size: 33
#-----------------------------------------------------------------------
# Hosts
#-----------------------------------------------------------------------
host1:
DSN: h=192.168.100.101,P=3306
hostname: server01
MySQL: MySQL Community Server (GPL) 5.7.20
host2:
DSN: h=192.168.100.103,P=3306
hostname: server03
MySQL: MySQL Community Server (GPL) 5.7.20
#-----------------------------------------------------------------------
# Stats
#-----------------------------------------------------------------------
empty_query 1
failed_queries 0
not_select 0
queries_filtered 0
queries_no_diffs 0
queries_read 1
queries_with_diffs 0
queries_with_errors 0