Manual:comment table

The comment table stores edits, blocks, and other actions which typically have a textual comment describing the action. They are stored in a separate table to reduce the size of the main tables, and to allow for de-duplication.

De-duplication is currently best-effort to avoid locking on inserts that would be required for strict de-duplication. There may be multiple rows with the same comment_text and comment_data .

This table was introduced in Gerrit change 357892.

Unique ID to identify each comment.

Hash of comment_text and comment_data , for de-duplication. The current algorithm is a signed CRC32 of the comment text XOR'd with a CRC32 of any comment data.

Text comment summarizing the change, e.g. an editor's edit summary. This text is shown in the history and contributions . It is also used for recent changes , related changes , watchlists , and, in the case of page creation, for the list of new pages . It is rendered in a sanitized subset of wiki markup by MediaWiki\CommentFormatter\CommentFormatter::format(). Size limits are enforced at the application level, and should take care to crop UTF-8 strings appropriately.

JSON data, intended for localizing auto-generated comments. This holds structured data that is intended to be used to provide localized versions of automatically-generated comments. When not empty, comment_text should be the generated comment localized using the wiki's content language.

DESCRIBEcomment;

+--------------+---------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+--------------+---------------------+------+-----+---------+----------------+
| comment_id | bigint(20) unsigned | NO | PRI | NULL | auto_increment |
| comment_hash | int(11) | NO | MUL | NULL | |
| comment_text | blob | NO | | NULL | |
| comment_data | blob | YES | | NULL | |
+--------------+---------------------+------+-----+---------+----------------+

SHOWINDEXINcomment;

+---------+------------+--------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment |
+---------+------------+--------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+
| comment | 0 | PRIMARY | 1 | comment_id | A | 0 | NULL | NULL | | BTREE | | |
| comment | 1 | comment_hash | 1 | comment_hash | A | 0 | NULL | NULL | | BTREE | | |
+---------+------------+--------------+--------------+--------------+-----------+-------------+----------+--------+------+------------+---------+---------------+

• Maintained by Unknown or Unassigned^{[‍Maintainers page]}.
• Issue tracker: Phabricator MediaWiki-Comment-Store (Report an issue)

• Linked tables
  • Manual:Revision table
  • Manual:Image table
  • Manual:Recentchanges table
  • Manual:Logging table
  • Manual:Ipblocks table
  • Manual:Protected titles table
  • Manual:Oldimage table , Manual:Archive table , Manual:Filearchive table
• PHP
  • Manual:CommentStore.php
  • Manual:CommentStoreComment.php
• Maintenance scripts
  • Manual:MigrateComments.php

• MediaWiki database tables