【数据库】几个实用的MySQL技巧

1. 重建rpmdb

有时候rpm数据库偶尔发生损坏，无法安装新rpm包：

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

这时候只需要重建就好了：

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

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