执行 pt-query-digest slow.log > digest.log 命令时报错：
[root@CentOS-CLI-MySql data]# pt-query-digest slow.log > digest.log
Can't locate Data/Dumper.pm in @INC
BEGIN failed--compilation aborted at /usr/local/toolkit/bin/pt-query-digest line 75.
原因是：缺少 Data-Dumper-2.154.tar.gz这个包，直接下载安装就ok了
wget http://www.cpan.org/modules/by-module/Data/Data-Dumper-2.154.tar.gz
tar xvzf Data-Dumper-2.154.tar.gz
cd Data-Dumper-2.121
perl Makefile.PL
make
make install
