Extension to support the tool pt-online-schema-change from Percona Toolkit.
This extension replaces a couple of the default changes to use pt-online-schema-change instead of SQL.
This allows to perform a non-locking database upgrade.
MySQL is the only supported database. The extension checks whether it is being run against a MySQL database. If not, it falls back to the default changes provided by liquibase-core.
The following changes are supported:
Since: liquibase-percona 1.0.0
Automatic rollback supported? yes
Example:
<changeSet id="2" author="Alice">
<addColumn tableName="person">
<column name="address" type="varchar(255)"/>
</addColumn>
</changeSet>Corresponding command:
pt-online-schema-change --alter="ADD COLUMN address VARCHAR(255)" ...Since: liquibase-percona 1.3.0
Automatic rollback supported? yes
Example:
<changeSet id="3" author="Alice">
<addForeignKeyConstraint constraintName="fk_person_address"
referencedTableName="person" referencedColumnNames="id"
baseTableName="address" baseColumnNames="person_id"/>
</changeSet>Corresponding command:
pt-online-schema-change --alter="ADD CONSTRAINT fk_person_address FOREIGN KEY (person_id) REFERENCES person (id)" ...Since: liquibase-percona 1.3.0
Automatic rollback supported? yes
Example:
<changeSet id="2" author="Alice">
<addUniqueConstraint columnNames="id, name" tableName="person" constraintName="uq_id_name"/>
</changeSet>Corresponding command:
pt-online-schema-change --alter="ADD CONSTRAINT uq_id_name UNIQUE (id, name)" ...Note: pt-online-schema-change is executed with the option --nocheck-unique-key-change. This enables to
add a unique index, but can cause data loss, since duplicated rows are ignored.
See Percona Toolkit Documentation
for more information.
Since: liquibase-percona 1.2.0
Automatic rollback supported? yes
Example:
<changeSet id="2" author="Alice">
<createIndex indexName="emailIdx" tableName="person" unique="true">
<column name="email"/>
</createIndex>
</changeSet>Corresponding command:
pt-online-schema-change --alter="ADD UNIQUE INDEX emailIdx (email)" ...Note: pt-online-schema-change is executed with the option --nocheck-unique-key-change. This enables to
add a unique index, but can cause data loss, since duplicated rows are ignored.
See Percona Toolkit Documentation
for more information.
Since: liquibase-percona 1.0.0
Automatic rollback supported? no
Example:
<changeSet id="2" author="Alice">
<dropColumn tableName="person" columnName="age"/>
</changeSet>Corresponding command:
pt-online-schema-change --alter="DROP COLUMN age" ...Since: liquibase-percona 1.3.0
Automatic rollback supported? no
Example:
<changeSet id="4" author="Alice">
<dropForeignKeyConstraint baseTableName="address" constraintName="fk_person_address" />
</changeSet>Corresponding command:
pt-online-schema-change --alter="DROP FOREIGN KEY _fk_person_address" ...Since: liquibase-percona 1.3.0
Automatic rollback supported? no
Example:
<changeSet id="3" author="Alice">
<dropUniqueConstraint tableName="person" constraintName="uq_id_name"/>
</changeSet>Corresponding command:
pt-online-schema-change --alter="DROP KEY uq_id_name" ...Since: liquibase-percona 1.2.0
Automatic rollback supported? no
Example:
<changeSet id="3" author="Alice">
<dropIndex indexName="emailIdx" tableName="person"/>
</changeSet>Corresponding command:
pt-online-schema-change --alter="DROP INDEX emailIdx" ...Since: liquibase-percona 1.2.0
Automatic rollback supported? no
Example:
<changeSet id="2" author="Alice">
<modifyDataType tableName="person" columnName="email" newDataType="VARCHAR(400)"/>
</changeSet>Corresponding command:
pt-online-schema-change --alter="MODIFY email VARCHAR(400)" ...Each change allows to enable or disable the usage of percona toolkit via the property usePercona.
By default, the percona toolkit is used, see also the system property liquibase.percona.defaultOn.
Example:
- changeSet:
id: 2
author: Alice
changes:
- addColumn:
tableName: person
usePercona: false
columns:
- column:
name: address
type: varchar(255)This flag exists since liquibase-percona 1.3.0
It is supported by using the YAML format and since liquibase 3.6.0, you can use it in XML changesets, too:
<addColumn tableName="person" xmlns:liquibasePercona="http://github.com/adangel/liquibase-percona" liquibasePercona:usePercona="false">
<column name="address" type="varchar(255)"/>
</addColumn>The extension supports the following java system properties:
liquibase.percona.failIfNoPT: true/false. Default: false.
If set to true, the database update will fail, if the command pt-online-schema-change is not found.
This can be used, to enforce, that percona toolkit is used.
liquibase.percona.noAlterSqlDryMode: true/false. Default: false.
When running updateSQL or rollbackSQL in order to generate a migration SQL file, the command line, that would
be executed, will be added as a comment.
In addition, the SQL statements (as produced by liquibase-core) will also be generated and output into the migration
file. This allows to simply execute the generated migration SQL to perform an update. However, the Percona toolkit
won't be used.
If this property is set to true, then no such SQL statements will be output into the migration file.
liquibase.percona.skipChanges: comma separated list of changes. Default: <empty>.
This option can be used in order to selectively disable one or more changes. If a change is disabled, then
the change will be executed by the default liquibase core implementation and percona toolkit won't be used.
By default, this property is empty, so that all supported changes are executed using the percona toolkit.
Example: Set this to addColumn,dropColumn in order to not use percona for adding/dropping a column.
liquibase.percona.options: String of options. Default: --alter-foreign-keys-method=auto --nocheck-unique-key-change.
Since liquibase-percona 1.2.1. Default value changed with liquibase-percona 1.6.0.
This option allows the user to pass additional command line options to pt-online-schema-change. This e.g. can
be used in complicated replication setup to change the way slaves are detected and how their state is used.
You can also specify a percona configuration file via --config file.conf,
see Configuration Files.
Multiple options are separated by space. If argument itself contains a space, it must be quoted with
double-quotes, e.g. --config "filename with spaces.conf".
liquibase.percona.defaultOn: true/false. Default: true. Since liquibase-percona 1.3.0
This options allows to change the default behavior for the UsePercona flag. By default,
all changes, that do not explicitly specify this flag, use the value from this system property.
Settings this property to false allows to control for each single change, whether to use Percona Toolkit
or not.
liquibase.password: String with the password needed to connect to the database. Default: <empty>.
Since liquibase-percona 1.4.0.
With this property, you can shortcut the automatic detection of the password from the underlying
java.sql.Connection (if that fails) or from the default liquibase.properties file. If this property is set,
then it is used for the password when executing pt-online-schema-change.
liquibase.percona.path: Path to the percona toolkit directory, where the tool
pt-online-schema-change is installed. Default: <empty>.
Since liquibase-percona 1.4.1.
With this property, you can select a specific toolkit installation. If this property is not set, then the
toolkit will be searched on the PATH. You need to specify the bin subfolder of the Percona Toolkit
distribution.
liquibase.percona.ptdebug: true/false. Default: false. Since liquibase-percona 1.5.0
This option enables the debug output of pt-osc by setting the environment variable PTDEBUG before
starting pt-osc.
You can set these properties by using the standard java -D option:
java -Dliquibase.percona.skipChanges=createIndex,dropColumn -jar liquibase.jar ...Note: You'll have to call liquibase via "java -jar" as otherwise the system property cannot be set. You'll also need to make sure, that the liquibase-percona.jar file is on the classpath via the "--classpath" option.
When executing liquibase through maven, you can use the Properties Maven Plugin to set the system property. An example can be found in the "createIndexSkipped" integration test.
The minimum Java runtime version is now Java 1.7.
The system property liquibase.percona.options uses now a default value of --alter-foreign-keys-method=auto --nocheck-unique-key-change.
These two options are not added by default anymore when pt-osc is executed. They are added
now via the additional options system property. In case you have overridden this system property, make sure, to add
these options as well, if you need them.
pt-online-schema-change is executed now with the option --nocheck-unique-key-change.
This enables to add unique indexes, but can cause data loss, since duplicated rows are ignored.
See Percona Toolkit Documentation
for more information.
The plugin is only compatible with version 3.0.12 or later of Percona Toolkit.
liquibase.percona.path to specify the path where Percona Toolkit is installed.The jar files can be downloaded manually from maven:
http://repo.maven.apache.org/maven2/com/github/adangel/liquibase/ext/liquibase-percona/
After extracting the zip file of liquibase, place liquibase-percona-1.6.0.jar file in the sub directory lib.
The shell script liquibase / liquibase.bat will automatically pick this up and the extension is available.
Add the following dependency to the liquibase plugin:
<dependency>
<groupId>com.github.adangel.liquibase.ext</groupId>
<artifactId>liquibase-percona</artifactId>
<version>1.6.0</version>
</dependency>Snapshot builds contain the latest features which are not yet available in a release.
Enable the snapshot repository via Maven:
<project>
<pluginRepositories>
<pluginRepository>
<id>sonatype-nexus-snapshots</id>
<name>Sonatype Nexus Snapshots</name>
<url>https://oss.sonatype.org/content/repositories/snapshots</url>
<releases>
<enabled>false</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
</snapshots>
</pluginRepository>
</pluginRepositories>
</project>See also https://maven.apache.org/guides/development/guide-testing-development-plugins.html.
And just use the latest SNAPSHOT version for liquibase-percona dependency, e.g. 1.6.1-SNAPSHOT:
<dependency>
<groupId>com.github.adangel.liquibase.ext</groupId>
<artifactId>liquibase-percona</artifactId>
<version>1.6.1-SNAPSHOT</version>
</dependency>The non-locking update is achieved using triggers. First a new temporary table is created, including the added or dropped columns. Then the data is copied in chunks. While the copy is in progress, any newly created or deleted or updated rows are copied, too. This is done by adding triggers to the original table. After the copy is finished, the original table is dropped and the temporary table is renamed.
This means, that pt-online-schema-change cannot be used, if the table already uses triggers.
The command pt-online-schema-change is searched only on the PATH. Depending on the property
liquibase.percona.failIfNoPT the update will fail or will just run without using pt-online-schema-change and
potentially lock the table for the duration of the update.
Simply run ./mvnw clean verify.
You'll find the jar-file in the target/ subdirectory.
In order to execute the integration tests, run ./mvnw clean verify -Prun-its.
Please note, that you'll need:
sudo apt-get install docker.io.PATH.sudo apt-get install libdbd-mysql-perl.See the properties config_... in pom.xml for connection details for the mysql docker instance.
To run a single integration test, execute maven like this: ./mvnw verify -Prun-its -Dinvoker.test=addColumn*,dropColumn
The full error message:
Unexpected error running Liquibase: liquibase.exception.UnexpectedLiquibaseException:
java.lang.NoSuchMethodError: liquibase.ext.percona.PerconaDropColumnChange.getColumns()Ljava/util/List;This means, you are trying to use version 1.1.1 of the extension with liquibase 3.2.x. This is an unsupported combination. For Liquibase 3.2.x, you'll need to use liquibase-percona 1.0.0
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