问为什么i386包安装在64位系统上？

EN

[root@rt ~]# yum install mysql-server mysql

Resolving Dependencies
--> Running transaction check
---> Package mysql.i386 0:5.0.77-4.el5_6.6 set to be updated
--> Processing Dependency: perl(DBI) for package: mysql
---> Package mysql.x86_64 0:5.0.77-4.el5_6.6 set to be updated
---> Package mysql-server.x86_64 0:5.0.77-4.el5_6.6 set to be updated
--> Processing Dependency: perl-DBD-MySQL for package: mysql-server
--> Running transaction check
---> Package perl-DBD-MySQL.x86_64 0:3.0007-2.el5 set to be updated
---> Package perl-DBI.x86_64 0:1.52-2.el5 set to be updated
--> Finished Dependency Resolution

Dependencies Resolved

===================================================================================
 Package                Arch           Version                  Repository    Size
===================================================================================
Installing:
 mysql                  i386           5.0.77-4.el5_6.6         base         4.8 M
 mysql                  x86_64         5.0.77-4.el5_6.6         base         4.8 M
 mysql-server           x86_64         5.0.77-4.el5_6.6         base         9.8 M
Installing for dependencies:
 perl-DBD-MySQL         x86_64         3.0007-2.el5             base         148 k
 perl-DBI               x86_64         1.52-2.el5               base         600 k

Transaction Summary
===================================================================================
Install       5 Package(s)
Upgrade       0 Package(s)

Total download size: 20 M
Is this ok [y/N]: