wb_changes

The change buffer holds information about each change, stored in the wb_changes table, to be accessed by the client wikis when processing the respective change. This is similar to MediaWiki's recentchanges table. The table structure is as follows:

Part of the md_docs_topics_change-propagation system on a Repo.

Fields:

• change_id
  • An int(10) with an autoincrement id identifying the change.
• change_type
  • A varchar(25) representing the kind of change. It has the form ''wikibase-<entity-type>~<action>'', e.g. “wikibase-item~add”.
  • Well known entity types are “item” and “property”. Custom entity types will define their own type names.
  • Known actions: “update”, “add”, “remove”, “restore”
• change_time
  • A binary(14) the time at which the edit was made
• change_object_id
  • A varbinary(14) containing the entity ID
• change_revision_id
  • A int(10) containing the revision ID
• change_user_id
  • A int(10) containing the original (repository) user id, or 0 for logged out users.
• change_info
  • A mediumblob containing a JSON structure with additional information about the change. Well known top level fields are:
    • “diff”
      • A serialized diff, as produced by EntityDiffer
    • “metadata”
      • A JSON object representing essential revision meta data, using the following fields:
        • “central_user_id”
          • The central user ID (int). 0 if the repo is not connected to a central user system, the action was by a logged out user, the particular user is not attached on the repo, or the user is restricted (uses AUDIENCE_PUBLIC)
        • “user_text”
          • The user name (string)
        • “page_id”
          • The id of the wiki page containing the entity on the repo (int)
        • “rev_id”
          • The id of the revision created by this change on the repo (int)
        • “parent_id”
          • The id of the parent revision of this change on the repo (int)
        • “comment”
          • The edit summary for the change
        • “bot”
          • Whether the change was performed as a bot edit (0 or 1)

+--------------------+------------------+------+-----+---------+----------------+
| Field              | Type             | Null | Key | Default | Extra          |
+--------------------+------------------+------+-----+---------+----------------+
| change_id          | int(10) unsigned | NO   | PRI | NULL    | auto_increment |
| change_type        | varbinary(25)    | NO   | MUL | NULL    |                |
| change_time        | binary(14)       | NO   | MUL | NULL    |                |
| change_object_id   | varbinary(14)    | NO   | MUL | NULL    |                |
| change_revision_id | int(10) unsigned | NO   | MUL | NULL    |                |
| change_user_id     | int(10) unsigned | NO   | MUL | NULL    |                |
| change_info        | mediumblob       | NO   |     | NULL    |                |
+--------------------+------------------+------+-----+---------+----------------+

Implied relations:

Extra Indexes:

• change_type
• change_time
• change_object_id
• change_user_id
• change_revision_id