1 files changed, 41 insertions, 0 deletions
diff --git a/db/post_migrate/20220326161803_add_cascade_delete_fk_on_project_namespace_id.rb b/db/post_migrate/20220326161803_add_cascade_delete_fk_on_project_namespace_id.rb
new file mode 100644
index 00000000000..005532c53d9
--- /dev/null
+++ b/db/post_migrate/20220326161803_add_cascade_delete_fk_on_project_namespace_id.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+class AddCascadeDeleteFkOnProjectNamespaceId < Gitlab::Database::Migration[1.0]
+  disable_ddl_transaction!
+
+  TARGET_COLUMN = :project_namespace_id
+
+  def up
+    # add the new FK before removing the old one
+    add_concurrent_foreign_key(
+      :projects,
+      :namespaces,
+      column: TARGET_COLUMN,
+      name: fk_name("#{TARGET_COLUMN}_new"),
+      on_delete: :cascade
+    )
+
+    with_lock_retries do
+      remove_foreign_key_if_exists(:projects, column: TARGET_COLUMN, name: fk_name(TARGET_COLUMN))
+    end
+  end
+
+  def down
+    add_concurrent_foreign_key(
+      :projects,
+      :namespaces,
+      column: TARGET_COLUMN,
+      name: fk_name(TARGET_COLUMN),
+      on_delete: :nullify
+    )
+
+    with_lock_retries do
+      remove_foreign_key_if_exists(:projects, column: TARGET_COLUMN, name: fk_name("#{TARGET_COLUMN}_new"))
+    end
+  end
+
+  def fk_name(column_name)
+    # generate a FK name
+    concurrent_foreign_key_name(:projects, column_name)
+  end
+end