Manual:revision_comment_temp table
↑ 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
editrevcomment_rev
editKey to revision.rev_id
revcomment_comment_id
editKey to comment.comment_id
Schema summary
editMediaWiki 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
editMediaWiki 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 | | | +-----------------------+------------+----------------+--------------+-----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+