OnlineSchemaChange
OnlineSchemaChange is a tool for making schema changes for MySQL tables in a non-blocking way
Examples
OSC
must be run on the same host as MySQL server.
copy
mode
Say we have an existing table named my_table
under database
test
:
CREATE TABLE `my_table` (
`id` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
Now if we want to run
ALTER TABLE `my_table` add column `data` varchar(10);
against
it. Instead of feed the ALTER TABLE
statement to OSC, we just need
to put a CREATE TABLE
statement representing the desired schema into
a file /tmp/foo.sql
like below:
CREATE TABLE `my_table` (
`id` int(11) NOT NULL,
`data` varchar(10) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1
Then run the following command:
osc_cli copy --ddl-file-list=foo.sql --socket=/tmp/mysql.socket --database=test
cleanup
mode
To cleanup the table left behind by last run of OSC
osc_cli cleanup --socket=/tmp/mysql.socket --database=test
To terminate a currently running OSC
process on certain MySQL
Instance:
osc_cli cleanup
direct
mode
This mode is reserved for utilizing MySQL's native online ddl for schema
change, and help DBA manage all the schema related operation into this
one tool. For now, if you plan to use OSC
for all your schema
management, this mode is here for you to create a empty new table.
Following command will create an empty table into database test
osc_cli direct --ddl-file-list=foo.sql --socket=/tmp/mysql.socket --database=test
Requirements
OnlineSchemaChange requires
System packages
sudo apt-get install python3-dev # debian / Ubuntu
sudo yum install python3-devel # Red Hat / CentOS
Python requirements * python >= 3.5 * python module: pyparsing, MySQLdb
Installing OnlineSchemaChange
Run following command to install dependency
python setup.py install --install-scripts=/usr/local/bin
If you have multiple python version available in your environment, or
you don't want mess up with system's default python, you can use
pyenv
and virtualenv
How OnlineSchemaChange works
Check wiki page for more detail, and some advanced usage.
How to contribute
Check this wiki page if you want to contribute to this project.
License
OnlineSchemaChange is BSD-licensed.