The revision_comment_temp table is a temporary table creating a relation between each row of the revision table and a row of the comment table. It has been created to avoid blocking on an alter of the revision table. On large wikis like the English Wikipedia, altering the revision table is a months-long process. This table is being created to avoid such an alter, and will be merged back into the revision table in the future.

This table was introduced in Gerrit change 357892. See also the image_comment_temp table.

Fields

Schema summary

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

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      |         |               |
+-----------------------+------------+----------------+--------------+-----------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+