Drop and Recreate Auto_increment Index MYSQL

To prevent very large auto_increment indices sometimes it is good to reset the indices, so they can start again from 1, 2,3 4 …
You would want to do that if you are using one table and there are no relationships associated with the primary key of that table. An example of that could be when you import a large csv into MySQL, removing and importing the data over and over again.

First: drop the old one
ALTER TABLE test DROP COLUMN id;

Second: Recreate the index
ALTER TABLE test ADD COLUMN id INT UNSIGNED NOT NULL AUTO_INCREMENT, ADD PRIMARY KEY (ID);

Update Centos 5.7 to 6.2

How to Update my Centos 5.7 server  to  the new 6.2 version?

Upgrading from 5.7 to 6.2 is a major upgrade, contrary to upgrading your system from 5.6 to 5.7, which is a minor upgrade.

yum can handle the minor upgrades.

Major upgrades apparently are not supported.
http://centos.org/modules/newbb/viewtopic.php?topic_id=36050&forum=55

So if you want to upgrade your server from 5.7 to 6.2 , you are on your own.
The best way is too implement a new centos 6.2 server and transfer your files.

Centos 5 Base Repos

If you change your Centos Repo and you want to restore the original repos, here are the ones that Centos comes with out of the box:

[base]
name=CentOS-$releasever - Base
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
#baseurl=http://mirror.centos.org/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#released updates
[updates]
name=CentOS-$releasever - Updates
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
#baseurl=http://mirror.centos.org/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
#baseurl=http://mirror.centos.org/centos/$releasever/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
#baseurl=http://mirror.centos.org/centos/$releasever/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5

#contrib - packages by Centos Users
[contrib]
name=CentOS-$releasever - Contrib
mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contrib
#baseurl=http://mirror.centos.org/centos/$releasever/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5