I passed a site from d7 to d8 I wanted to know if I can delete tables db migrate map d7 and migrate messages d7 they are more than a hundred I can delete db tables migrate map d7 and migrate d7 messages of types of content that no longer exist on d8?




  • 1
    You probably have a copy of your site running locally, no? So, simply make a database backup, delete those tables, see what happens. If FUBAR, drop DB and import the backup. No?
    – leymannx
    Mar 22, 2019 at 15:40
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    If you sure about completed migrations. You can uninstall module and deleted all table _map and _message of migrations. It's safe.
    – Jonh
    Mar 22, 2019 at 15:59

1 Answer 1


Yes. If you're doing a "one-and-done" migration you can remove the tables. Just make sure to:

  • uninstall the migration modules
  • remove your relevant migration config
  • then remove your DB tables once you have no code/config dependant on these tables.

Note, the caveat is you're wiping out your migration history.

The migration framework has an ongoing issue about this topic. These tables are persisted since these they capture migration source/destination metadata. The metadata is important if you have a phased, or ongoing, migration. If your migration project is over, the metadata has no relevance.

  • Yep, once you uninstall there’s no going back unless you have a copy of the db before migration.
    – Kevin
    Mar 22, 2019 at 20:40

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