Removing IsTemporal()

Remove the IsTemporal() call from an entity, or remove the entity from the model altogether, and the migration keeps the history table, columns, data and indexes included. The same rule as for a removed property applies one level up: the table stays in the model, tagged Hindsight:Orphaned, so no generated migration ever drops it.

• If the entity is still mapped, its main table keeps evolving normally. Only the history table is pinned as it was.
• The history table is kept for its data, not for queries. AsOf, AllVersions and History<T> require a temporal entity, so they throw InvalidOperationException for this one. Query the table with SQL if you need to.
• Once orphaned, it stays in every later model, so nothing has to rediscover it.

With the trigger writer

This is the one case where a generated migration drops something on its own. The trigger lives on the main table and would otherwise keep writing into a history table the model no longer considers temporal. So the migration that removes IsTemporal() runs DROP FUNCTION … CASCADE, which also drops the trigger. No data is deleted; only the writing stops. This happens once, in that migration.

Dropping the history table

If you really want the history table gone, write a migration that drops it yourself. Hindsight never will.