Manual:$wgCommentTableSchemaMigrationStage

Miscellaneous settings: $wgCommentTableSchemaMigrationStage
comment table schema migration stage.
Introduced in version:	1.30.0 (Gerrit change 357892; git #Ic3a434c)
Removed in version:	1.33.0 (Gerrit change 482371; git #0abb9338)
Allowed values:	See below
Default value:	MIGRATION_OLD
Other settings: Alphabetical | By function

$wgCommentTableSchemaMigrationStage indicates the comment table schema migration stage. Most wikis can set this to MIGRATION_NEW and run maintenance/migrateComments.php as soon as any necessary extensions are updated.

Details

$wgCommentTableSchemaMigrationStage can be set to one of the Schema change migration flags. The allowed value range for the configuration is one of the MIGRATION_* constants. The available constants and their planned use cases on Wikimedia Foundation wikis are as follows:

• MIGRATION_OLD (0, default value) - Only read and write the old schema. The new schema need not even exist. This is used from when the patch is merged until the schema change is actually applied to the database.
• MIGRATION_WRITE_BOTH (1) - Write both the old and new schema. Read the new schema preferentially, falling back to the old. This is used while the change is being tested, allowing easy roll-back to the old schema.
• MIGRATION_WRITE_NEW (2) - Write only the new schema. Read the new schema preferentially, falling back to the old. This is used while running the maintenance script to migrate existing entries in the old schema to the new schema.
• MIGRATION_NEW (3) - Only read and write the new schema. The old schema (and the feature flag) may now be removed.

For non-Wikimedia Foundation wikis it is recommended to set this to MIGRATION_NEW and to run maintenance/migrateComments.php in order to take advantage of the new schema.

$wgForeignFileRepos

If you operate a wiki farm using $wgForeignFileRepos with ForeignDBRepo or ForeignDBViaLBRepo, it is important to keep in mind that client and repository wiki must be in nearby migration stages. (see T181930)

		Foreign repo wiki
		No schema change	OLD	WRITE_BOTH	WRITE_NEW	NEW	Fields dropped
Client wiki	No schema change	Yes	Yes	Yes	No	No	No
	OLD	Yes	Yes	Yes	No	No	No
	WRITE_BOTH	No	Yes	Yes	Yes	Yes	No
	WRITE_NEW	No	Yes	Yes	Yes	Yes	No
	NEW	No	No	Yes	Yes	Yes	Yes
	Fields dropped	No	No	Yes	Yes	Yes	Yes