Database Migration

As features are added to Ministry.Chat, the database schema may change between versions.

The action of updating an older schema to a newer one (or vice versa) is called database migration.

When you incrementally update Ministry.Chat versions, database migration is automatic and you do not have to take any explicit action.

However, from time to time, you may need to skip multiple versions in your Ministry.Chat upgrades.

Database migration may fail in a scenario like this.

A typical failure message is similar to:

|                    Your database migration failed:                   |
|        Object [object Object] has no method 'addUsersToRoles'        |
(...)
|                   This Ministry.Chat version: 0.39.0                   |
|                    Database locked at version: 18                    |
|                      Database target version: 58                     |

As an example, the migration above is locked and stuck on 18. We need a target of 19 before migrating to 58.

One way to force this migration is to manually unlock the migration in Mongo and also increase the database version to the target version (19).

use rocketchat
db.migrations.update({_id: 'control'},{$set:{locked:false,version:19}})

Restart Ministry.Chat and the migration should succeed now to the latest version.

Note: certain new values that are vital to Ministry.Chat operations may remain unpopulated when you skip versions. For example, you may have to manually apply roles to users.