joystream/testnets/rome/specification/runtime/migration-module.md

Migration Module

Table of Contents

• Design
• Name
• Dependencies
• Concepts
• State
• Events
• on_initialize

Design

Motivation

The purpose of this module is to run migration routines required in the upgrading from Athens to Acropolis network through an on-chain runtime upgrade.

Function

Routines run when the on_initialize dispatchable is invoked. In the upgrade to Acropolis there are no other modules which have similar code in their own handler of this callback which depend on the migration having being executed. This means it is immaterial in what order the migration module is invoked, however in the future care must be made to guarantee the migration module running first.

Name

Migration

Dependencies

• Data Directory Module

• Data Object Storage Registry Module

• Sudo SRML Module

Concepts

Standard.

State

• SpecVersion: If set, what runtime spec version the store was initialised, otherwise not set.

Events

• Migrated: Runtime migration code was executed
  • block number of migration
  • spec version

on_initialize

Description

Pre-block execution code which actually performs migration and initialization under suitable conditions, namely

• SpecVersion is not set, which would possibly be the case from genesis
• SpecVersion is less than the runtime spec version

Event(s)

• Migrated

Side effect(s)

• SpecVersion is set to spec version.

Forum

• NextCategoryId is 1
• NextThreadId is 1
• NextPostId is 1
• ForumSudo is key in Sudo module.
• CategoryTitleConstraint is (10,90)
• CategoryDescriptionConstraint is (10, 490)
• ThreadTitleConstraint is (10, 90)
• PostTextConstraint is (10, 990)
• ThreadModerationRationaleConstraint is (10, 290)
• PostModerationRationaleConstraint is (10, 290)

DataDirectory

• PrimaryLiaisonAccountId is gone.
• KnownContentIds, DataObjectByContentId and MetadataByContentId are all empty.

DataObjectStorageRegirstry

• RelationshipsByContentId is empty.