migrate_delete

Module provides administration tools to safely delete migration related database tables (migrate_map_* and migrate_message_*). This module is designed for Drupal sites that have completed migrations and no longer need the migration tracking tables. It's particularly useful for cleaning up databases after successful migration projects.

Warning

This action cannot be undone. Once migration tables are deleted, all migration tracking data and error messages will be permanently lost. Only use this module when you are certain you no longer need migration data. Make a database backup before using.

Installation

Composer require drupal/migrate_delete

Enable the module through the Drupal admin ui or with Drush:

drush en migrate_delete

Usage

Web UI

Navigate to Configuration > System > Delete Migration Tables (/admin/config/system/migrate-delete)
Review the list of migration tables that will be deleted
Check the confirmation checkbox to acknowledge that this action cannot be undone
Click "Delete all migration tables" to proceed

Drush Commands

The module provides two Drush cli commands:

List Migration Tables

# List all migration tables
drush migrate-delete:list

# or use the alias
drush mdl

This command will show:

Count of migration tables found
Migration map tables (migrate_map_*)
Migration message tables (migrate_message_*)

Delete Migration Tables

# Delete all migration tables
drush migrate-delete:delete

# or use the alias
drush mdd

# Delete without confirmation (use with caution!)
drush migrate-delete:delete -y

# or
drush mdd -y

The delete command will:

List all tables that will be deleted
Show a warning about permanent data loss
Require confirmation (unless -y flag is used)
Provide real-time feedback during deletion
Show a summary of results

Features

Detailed Listing: Shows all tables that will be deleted, grouped by type
Safe Table Detection: Only finds and lists actual migration tables matching the expected patterns
User Confirmation: Requires explicit confirmation before deletion
Security Validation: Validates table names to prevent unauthorized deletions
Error Handling: Provides clear feedback on success or failure
Drush Integration: Full command-line support with list and delete operations

Security Considerations

Tables are validated against expected naming patterns before deletion
Provides multiple confirmation steps to prevent accidental deletion

What Gets Deleted

This module will delete:

All tables starting with migrate_map_*
All tables starting with migrate_message_*

These tables contain:

Migration mapping data between source and destination entities
Migration error messages and debugging information

Drush Command Examples

List all migration tables:

$ drush migrate-delete:list
Found 10 migration tables:

Migration Map Tables (5):
  - migrate_map_d7_block
  - migrate_map_d7_comment
  - migrate_map_d7_node_article
  - migrate_map_d7_taxonomy_term
  - migrate_map_d7_user

  Migration Message Tables (5):
  - migrate_message_d7_block
  - migrate_message_d7_comment  
  - migrate_message_d7_node_article
  - migrate_message_d7_taxonomy_term
  - migrate_message_d7_user

Use "drush migrate-delete:delete" to delete these tables.

Delete migration tables:

$ drush migrate-delete:delete
Found 10 migration tables that will be deleted:
  Map tables (5): migrate_map_d7_block, migrate_map_d7_comment, ...
  Message tables (5): migrate_message_d7_block, migrate_message_d7_comment, ...

WARNING: This action cannot be undone!

Are you sure you want to delete all these migration tables? (y/N): y

Deleting migration tables...
  ✓ Deleted: migrate_map_d7_block
  ✓ Deleted: migrate_map_d7_comment
  ✓ Deleted: migrate_message_d7_block
  ✓ Deleted: migrate_message_d7_comment
  ...

Successfully deleted 10 migration tables.

Delete migration tables without confirmation:

$ drush migrate-delete:delete -y
Found 10 migration tables that will be deleted:
  Map tables (5): migrate_map_d7_block, migrate_map_d7_comment, ...
  Message tables (5): migrate_message_d7_block, migrate_message_d7_comment, ...

WARNING: This action cannot be undone!

Deleting migration tables...
  ✓ Deleted: migrate_map_d7_block
  ✓ Deleted: migrate_map_d7_comment
  ...

Successfully deleted 10 migration tables.

Recommended modules/libraries

Drush