By Alvin Alexander. Last updated: June 6, 2016
FWIW, it appears that you can drop all of the “migrate” database tables that end up in your Drupal 8 database after a migration, such as migrating from Drupal 6 to Drupal 8. I ended up with 178 of these migration tables in my Drupal 8 database, and deleted them like this:
SET FOREIGN_KEY_CHECKS = 0; drop table migrate_map_572fc072df61d; drop table migrate_map_572fc0731606b; drop table migrate_map_572fc07322bd1; drop table migrate_map_572fc0732a7a3; drop table migrate_map_572fc07332de0; drop table migrate_map_572fc0733be45; drop table migrate_map_572fc07344566; drop table migrate_map_572fc07349dba; drop table migrate_map_572fc07350128; drop table migrate_map_block_content_body_field; drop table migrate_map_block_content_type; drop table migrate_map_d6_comment; drop table migrate_map_d6_comment_entity_display; drop table migrate_map_d6_comment_entity_form_display; drop table migrate_map_d6_comment_entity_form_display_subject; drop table migrate_map_d6_comment_field; drop table migrate_map_d6_comment_field_instance; drop table migrate_map_d6_comment_type; drop table migrate_map_d6_custom_block; drop table migrate_map_d6_date_formats; drop table migrate_map_d6_dblog_settings; drop table migrate_map_d6_field; drop table migrate_map_d6_field_formatter_settings; drop table migrate_map_d6_field_instance; drop table migrate_map_d6_field_instance_widget_settings; drop table migrate_map_d6_file; drop table migrate_map_d6_file_settings; drop table migrate_map_d6_filter_format; drop table migrate_map_d6_imagecache_presets; drop table migrate_map_d6_node__blog; drop table migrate_map_d6_node__bookmark; drop table migrate_map_d6_node__inspirational_quote; drop table migrate_map_d6_node__page; drop table migrate_map_d6_node__photo; drop table migrate_map_d6_node__quotes; drop table migrate_map_d6_node__source_code; drop table migrate_map_d6_node__story; drop table migrate_map_d6_node__text; drop table migrate_map_d6_node_revision__blog; drop table migrate_map_d6_node_revision__bookmark; drop table migrate_map_d6_node_revision__inspirational_quote; drop table migrate_map_d6_node_revision__page; drop table migrate_map_d6_node_revision__photo; drop table migrate_map_d6_node_revision__quotes; drop table migrate_map_d6_node_revision__source_code; drop table migrate_map_d6_node_revision__story; drop table migrate_map_d6_node_revision__text; drop table migrate_map_d6_node_setting_promote; drop table migrate_map_d6_node_setting_status; drop table migrate_map_d6_node_setting_sticky; drop table migrate_map_d6_node_settings; drop table migrate_map_d6_node_type; drop table migrate_map_d6_search_settings; drop table migrate_map_d6_system_cron; drop table migrate_map_d6_system_date; drop table migrate_map_d6_system_file; drop table migrate_map_d6_system_image; drop table migrate_map_d6_system_image_gd; drop table migrate_map_d6_system_logging; drop table migrate_map_d6_system_maintenance; drop table migrate_map_d6_system_performance; drop table migrate_map_d6_system_rss; drop table migrate_map_d6_system_site; drop table migrate_map_d6_taxonomy_term; drop table migrate_map_d6_taxonomy_vocabulary; drop table migrate_map_d6_term_node__1; drop table migrate_map_d6_term_node__2; drop table migrate_map_d6_term_node__7; drop table migrate_map_d6_term_node_revision__1; drop table migrate_map_d6_term_node_revision__2; drop table migrate_map_d6_term_node_revision__7; drop table migrate_map_d6_upload; drop table migrate_map_d6_upload_entity_display; drop table migrate_map_d6_upload_entity_form_display; drop table migrate_map_d6_upload_field; drop table migrate_map_d6_upload_field_instance; drop table migrate_map_d6_url_alias; drop table migrate_map_d6_user; drop table migrate_map_d6_user_contact_settings; drop table migrate_map_d6_user_mail; drop table migrate_map_d6_user_picture_file; drop table migrate_map_d6_user_role; drop table migrate_map_d6_user_settings; drop table migrate_map_d6_view_modes; drop table migrate_map_d6_vocabulary_entity_display; drop table migrate_map_d6_vocabulary_entity_form_display; drop table migrate_map_d6_vocabulary_field; drop table migrate_map_d6_vocabulary_field_instance; drop table migrate_map_menu_settings; drop table migrate_map_search_page; drop table migrate_map_taxonomy_settings; drop table migrate_map_text_settings; drop table migrate_map_user_picture_entity_display; drop table migrate_map_user_picture_entity_form_display; drop table migrate_map_user_picture_field; drop table migrate_map_user_picture_field_instance; drop table migrate_message_572fc072df61d; drop table migrate_message_572fc0731606b; drop table migrate_message_572fc07322bd1; drop table migrate_message_572fc0732a7a3; drop table migrate_message_572fc07332de0; drop table migrate_message_572fc0733be45; drop table migrate_message_572fc07344566; drop table migrate_message_572fc07349dba; drop table migrate_message_572fc07350128; drop table migrate_message_block_content_body_field; drop table migrate_message_block_content_type; drop table migrate_message_d6_comment; drop table migrate_message_d6_comment_entity_display; drop table migrate_message_d6_comment_entity_form_display; drop table migrate_message_d6_comment_entity_form_display_subject; drop table migrate_message_d6_comment_field; drop table migrate_message_d6_comment_field_instance; drop table migrate_message_d6_comment_type; drop table migrate_message_d6_custom_block; drop table migrate_message_d6_date_formats; drop table migrate_message_d6_dblog_settings; drop table migrate_message_d6_field; drop table migrate_message_d6_field_formatter_settings; drop table migrate_message_d6_field_instance; drop table migrate_message_d6_field_instance_widget_settings; drop table migrate_message_d6_file; drop table migrate_message_d6_file_settings; drop table migrate_message_d6_filter_format; drop table migrate_message_d6_imagecache_presets; drop table migrate_message_d6_node__blog; drop table migrate_message_d6_node__bookmark; drop table migrate_message_d6_node__inspirational_quote; drop table migrate_message_d6_node__page; drop table migrate_message_d6_node__photo; drop table migrate_message_d6_node__quotes; drop table migrate_message_d6_node__source_code; drop table migrate_message_d6_node__story; drop table migrate_message_d6_node__text; drop table migrate_message_d6_node_revision__blog; drop table migrate_message_d6_node_revision__bookmark; drop table migrate_message_d6_node_revision__inspirational_quote; drop table migrate_message_d6_node_revision__page; drop table migrate_message_d6_node_revision__photo; drop table migrate_message_d6_node_revision__quotes; drop table migrate_message_d6_node_revision__source_code; drop table migrate_message_d6_node_revision__story; drop table migrate_message_d6_node_revision__text; drop table migrate_message_d6_node_setting_promote; drop table migrate_message_d6_node_setting_status; drop table migrate_message_d6_node_setting_sticky; drop table migrate_message_d6_node_settings; drop table migrate_message_d6_node_type; drop table migrate_message_d6_search_settings; drop table migrate_message_d6_system_cron; drop table migrate_message_d6_system_date; drop table migrate_message_d6_system_file; drop table migrate_message_d6_system_image; drop table migrate_message_d6_system_image_gd; drop table migrate_message_d6_system_logging; drop table migrate_message_d6_system_maintenance; drop table migrate_message_d6_system_performance; drop table migrate_message_d6_system_rss; drop table migrate_message_d6_system_site; drop table migrate_message_d6_taxonomy_term; drop table migrate_message_d6_taxonomy_vocabulary; drop table migrate_message_d6_term_node__1; drop table migrate_message_d6_term_node__2; drop table migrate_message_d6_term_node__7; drop table migrate_message_d6_term_node_revision__1; drop table migrate_message_d6_term_node_revision__2; drop table migrate_message_d6_term_node_revision__7; drop table migrate_message_d6_upload; drop table migrate_message_d6_upload_entity_display; drop table migrate_message_d6_upload_entity_form_display; drop table migrate_message_d6_upload_field; drop table migrate_message_d6_upload_field_instance; drop table migrate_message_d6_url_alias; drop table migrate_message_d6_user; drop table migrate_message_d6_user_contact_settings; drop table migrate_message_d6_user_mail; drop table migrate_message_d6_user_picture_file; drop table migrate_message_d6_user_role; drop table migrate_message_d6_user_settings; drop table migrate_message_d6_view_modes; drop table migrate_message_d6_vocabulary_entity_display; drop table migrate_message_d6_vocabulary_entity_form_display; drop table migrate_message_d6_vocabulary_field; drop table migrate_message_d6_vocabulary_field_instance; drop table migrate_message_menu_settings; drop table migrate_message_search_page; drop table migrate_message_taxonomy_settings; drop table migrate_message_text_settings; drop table migrate_message_user_picture_entity_display; drop table migrate_message_user_picture_entity_form_display; drop table migrate_message_user_picture_field; drop table migrate_message_user_picture_field_instance; SET FOREIGN_KEY_CHECKS = 1;
There may be a way to drop all those MySQL tables using a wildcard character, but honestly, I didn’t even try that. I just created a list of all of the tables, then used some TextMate macros to create all of those drop table commands, which took about two minutes.
I posted a question about these tables on drupal.org, but haven’t heard back on that in four days, so I just deleted the tables, and my Drupal 8 website still seems to be working fine. I’m just working on a Dev/Test website, so if the site didn’t work afterwards it was no big deal. I had a database backup that I could easily restore from.
In summary, if you were looking for a way to delete all those migrate* database tables after a Drupal 8 migration, I can tell you that I used this technique, and it seems to work fine.
