分享几个实用的技巧

rpmdb: Thread/process 21721/140622824318880 failed: Thread died in Berkeley DB library                
error: db3 error(-30974) from dbenv->failchk: DB_RUNRECOVERY: Fatal error, run database recovery                
error: cannot open Packages index using db3 -  (-30974)                
error: cannot open Packages database in /var/lib/rpm                
rpmdb: Thread/process 21721/140622824318880 failed: Thread died in Berkeley DB library                
error: db3 error(-30974) from dbenv->failchk: DB_RUNRECOVERY: Fatal error, run database recovery                
error: cannot open Packages database in /var/lib/rpm

mv /var/lib/rpm/__db* /tmp
yum clean all
yum update
rm -i /tmp/__db*

$ mysql_random_data_load -h127.0.0.1 -uroot  -pGreatSQL -P3306 --max-threads=4 testdb t1 1000

mysqlsh> shell.enablePager();
mysqlsh> shell.options["pager"]="less -i -n -S";

$ grep Lock_time: slow.log | head
# Query_time: 1.097620  Lock_time: 0.000000 Rows_sent: 0  Rows_examined: 0
# Query_time: 0.000111  Lock_time: 0.000060 Rows_sent: 1  Rows_examined: 1
# Query_time: 0.000462  Lock_time: 0.000120 Rows_sent: 2  Rows_examined: 544
...

$ grep Lock_time: slow.log | head | awk '{sum1+=$3;}END{print sum1}'
77.228