Core Platform Team/Initiative/MCR schema migration/Initiative Description

< MCR schema migration


Complete the schema migration tasks associated with the Multi-Content Revisions (MCR) project.

Significance and Motivation

This initiative is necessary to remove the tech debt remaining from the pre-MCR schema.


Writing to pre-MCR fields is disabled in WMF production. Pre-MCR fields can be dropped from the database at the discretion of DBAs. All code that writes pre-MCR fields has been removed from core.

Baseline Metrics

Some core in core and extensions still relies on information in pre-MCR fields in the database. This makes it impossible to stop writing to these fields.

Target Metrics

All code that accesses pre-MCR fields in the database is removed or gated with the MCR migration stage. This applies to core as well as deployed extensions and bundled extensions.


core developers, database admins

Known Dependencies/Blockers

None given