Manual:revision_comment_temp table
â Manual:Contents | MediaWiki database layout | revision_comment_temp table |
MediaWiki versions: | 1.30 – 1.40 |
The revision_comment_temp table was a temporary table creating a relation between each row of the revision table and a row of the comment table. It was created (along with the similar revision_actor_temp table) to avoid blocking on an alter of the revision table, which took . On large wikis like the English Wikipedia, altering the revision table is a months-long process. This table was created so that other data migrations could be done while the alter was running. Once adding the rev_comment_id field to the revision table was done, the data from revision_comment_temp was merged back into the revision table and the table was deleted.
This table was introduced in Gerrit change 357892. See also the image_comment_temp table.
Fields[edit]
revcomment_rev[edit]
Key to revision.rev_id
revcomment_comment_id[edit]
Key to comment.comment_id
Schema summary[edit]
MediaWiki versions: | 1.30 – 1.40 |
DESCRIBE revision_comment_temp;
+-----------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +-----------------------+---------------------+------+-----+---------+-------+ | revcomment_rev | int(10) unsigned | NO | PRI | NULL | | | revcomment_comment_id | bigint(20) unsigned | NO | PRI | NULL | | +-----------------------+---------------------+------+-----+---------+-------+
Indexes[edit]
MediaWiki versions: | 1.30 – 1.40 |
SHOW INDEX IN revision_comment_temp;
+-----------------------+------------+----------------+--------------+-----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | +-----------------------+------------+----------------+--------------+-----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | revision_comment_temp | 0 | PRIMARY | 1 | revcomment_rev | A | 0 | NULL | NULL | | BTREE | | | | revision_comment_temp | 0 | PRIMARY | 2 | revcomment_comment_id | A | 0 | NULL | NULL | | BTREE | | | | revision_comment_temp | 0 | revcomment_rev | 1 | revcomment_rev | A | 0 | NULL | NULL | | BTREE | | | +-----------------------+------------+----------------+--------------+-----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+