> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/server/reference/plugins/other-plugins/online_alter_log.md).

# online\_alter\_log

{% hint style="info" %}
This plugin is for internal use only.
{% endhint %}

This plugin represents the online alter log in a transaction. It is used to commit transactions for tables while an online `ALTER TABLE` query is running.

It is built in the server, and is always enabled.

See the [Online Schema Change](/docs/server/reference/sql-statements/data-definition/alter/alter-table/online-schema-change.md) page for functionality details.

For plugin version and maturity level, see [this page](/docs/server/reference/plugins/list-of-plugins.md).