Upgrading mysql database

The installing of mysql database is really a task but once you know how to intall the mysql then upgrading should not be a problem except few more parameters to consider.

The following items form a checklist of things that you should do whenever you perform an upgrade from MySQL 4.1 to 5.0:

Before any upgrade, back up your databases, including the mysql database that contains the grant tables.

Read all the notes in Section 2.18.2, “Upgrading from MySQL 4.1 to 5.0”. These notes will enable you to identify upgrade issues that apply to your current MySQL installation. Read Appendix E, MySQL Change History as well, which provides information about features that are new in MySQL 5.0 or differ from those found in MySQL 4.1.

For any incompatibilities that require your attention before upgrading, deal with them as described in Section 2.18.2, “Upgrading from MySQL 4.1 to 5.0”.

After you upgrade to a new version of MySQL, you should run mysql_upgrade (see Section 4.4.9, “mysql_upgrade — Check Tables for MySQL Upgrade”). This program will check your tables, and repair them if necessary. It will also update your grant tables to make sure that they have the current structure so that you can take advantage of any new capabilities. (Some releases of MySQL introduce changes to the structure of the grant tables to add new privileges or features.)

If you are running MySQL Server on Windows, see Section 2.9.14, “Upgrading MySQL on Windows”.

If you are using replication, see Section 15.3.3, “Upgrading a Replication Setup”, for information on upgrading your replication setup.

If you are upgrading an installation originally produced by installing multiple RPM packages, it is best to upgrade all the packages, not just some. For example, if you previously installed the server and client RPMs, do not upgrade just the server RPM.

MySQL 5.0.27 is the last version in MySQL 5.0 for which MySQL-Max binary distributions are provided, except for RPM distributions. For RPMs, MySQL 5.0.37 is the last release. After these versions, the features previously included in the mysqld-max server are included in mysqld.

If you previously installed a MySQL-Max distribution that includes a server named mysqld-max, and then upgrade later to a non-Max version of MySQL, mysqld_safe still attempts to run the old mysqld-max server. If you perform such an upgrade, you should remove the old mysqld-max server manually to ensure that mysqld_safe runs the new mysqld server.

You can always move the MySQL format files and data files between different versions on the same architecture as long as you stay within versions for the same release series of MySQL.

If you are cautious about using new versions, you can always rename your old mysqld before installing a newer one. For example, if you are using MySQL 4.1.13 and want to upgrade to 5.0.10, rename your current server from mysqld to mysqld-4.1.13. If your new mysqld then does something unexpected, you can simply shut it down and restart with your old mysqld.

If, after an upgrade, you experience problems with recompiled client programs, such as Commands out of sync or unexpected core dumps, you probably have used old header or library files when compiling your programs. In this case, you should check the date for your mysql.h file and libmysqlclient.a library to verify that they are from the new MySQL distribution. If not, recompile your programs with the new headers and libraries.

If problems occur, such as that the new mysqld server does not start or that you cannot connect without a password, verify that you do not have an old my.cnf file from your previous installation. You can check this with the --print-defaults option (for example, mysqld –print-defaults). If this command displays anything other than the program name, you have an active my.cnf file that affects server or client operation.

It is a good idea to rebuild and reinstall the Perl DBD::mysql module whenever you install a new release of MySQL. The same applies to other MySQL interfaces as well, such as the PHP mysql extension and the Python MySQLdb module.

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2. Possible corruptions in MYSQL database
3. Code quality in Mysql
4. Uploading huge database files to server
5. SET SQL_MODE=NO_AUTO_VALUE_ON_ZERO
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