Add FK for bigint conversion for .com

1. A FK needed for the bigint conversion work
for system_note_metadata's id column is added
added to the com database and validated asynchronously.

2. A unique index added in an earlier MR in the same milestone is no-oped.
The index should be added together when the FK is synchronously added.
To restore the dev environment to a consistent state,
a migration is added to remove the unique index.

Changelog: other

db/migrate/20240109031624_add_unique_index_to_system_note_metadata_on_id_convert_to_bigint.rb

@@ -5,14 +5,15 @@ class AddUniqueIndexToSystemNoteMetadataOnIdConvertToBigint < Gitlab::Database::
 
   milestone '16.9'
 
-  TABLE_NAME = :system_note_metadata
-  INDEX_NAME = 'index_system_note_metadata_pkey_on_id_convert_to_bigint'
-
   def up
-    add_concurrent_index TABLE_NAME, :id_convert_to_bigint, unique: true, name: INDEX_NAME
+    # no-op
+    # The index has been created asynchronously for GitLab.com
+    # The index is going to be used to back a primary key and a foreign key.
+    # Dropping the index would require dropping any foreign key associated with the index
+    # thus the index and the foreign key must be added in the same migration.
   end
 
   def down
-    remove_concurrent_index TABLE_NAME, :id_convert_to_bigint, unique: true, name: INDEX_NAME
+    # no-op
   end
 end

db/migrate/20240117055908_drop_unique_index_to_system_note_metadata_on_id_convert_to_bigint.rb

+# frozen_string_literal: true
+
+class DropUniqueIndexToSystemNoteMetadataOnIdConvertToBigint < Gitlab::Database::Migration[2.2]
+  disable_ddl_transaction!
+
+  milestone '16.9'
+
+  TABLE_NAME = :system_note_metadata
+  INDEX_NAME = 'index_system_note_metadata_pkey_on_id_convert_to_bigint'
+
+  def up
+    return if Gitlab.com?
+
+    remove_concurrent_index_by_name TABLE_NAME, INDEX_NAME
+  end
+
+  def down
+    return if Gitlab.com?
+
+    add_concurrent_index TABLE_NAME, :id_convert_to_bigint, unique: true, name: INDEX_NAME
+  end
+end

db/post_migrate/20240117070931_add_fk_to_resource_link_events_system_note_metadata_id_convert_to_bigint_for_com.rb

+# frozen_string_literal: true
+
+class AddFkToResourceLinkEventsSystemNoteMetadataIdConvertToBigintForCom < Gitlab::Database::Migration[2.2]
+  include Gitlab::Database::MigrationHelpers::ConvertToBigint # for the method `com_or_dev_or_test_but_not_jh?`
+
+  disable_ddl_transaction!
+
+  milestone '16.9'
+
+  TABLE_NAME = :resource_link_events
+  COLUMN = :system_note_metadata_id
+
+  TARGET_TABLE_NAME = :system_note_metadata
+  TARGET_COLUMN = :id_convert_to_bigint
+
+  INDEX_NAME = 'index_system_note_metadata_pkey_on_id_convert_to_bigint'
+  FK_NAME = 'fk_system_note_metadata_id_convert_to_bigint'
+
+  def up
+    return unless com_or_dev_or_test_but_not_jh?
+
+    add_concurrent_index(TARGET_TABLE_NAME, :id_convert_to_bigint, unique: true, name: INDEX_NAME)
+
+    add_concurrent_foreign_key(
+      TABLE_NAME,
+      TARGET_TABLE_NAME,
+      name: FK_NAME,
+      column: COLUMN,
+      target_column: TARGET_COLUMN,
+      on_delete: :cascade,
+      validate: false
+    )
+  end
+
+  def down
+    return unless com_or_dev_or_test_but_not_jh?
+
+    with_lock_retries do
+      remove_foreign_key_if_exists(
+        TABLE_NAME,
+        TARGET_TABLE_NAME,
+        name: FK_NAME,
+        reverse_lock_order: true
+      )
+    end
+
+    remove_concurrent_index_by_name(TARGET_TABLE_NAME, INDEX_NAME)
+  end
+end

db/post_migrate/20240117070946_validate_fk_on_resource_link_events_system_note_metadata_id_for_com.rb

+# frozen_string_literal: true
+
+class ValidateFkOnResourceLinkEventsSystemNoteMetadataIdForCom < Gitlab::Database::Migration[2.2]
+  include Gitlab::Database::MigrationHelpers::ConvertToBigint # for the method `com_or_dev_or_test_but_not_jh?`
+
+  milestone '16.9'
+
+  TABLE_NAME = :resource_link_events
+  COLUMN = :system_note_metadata_id
+  FK_NAME = 'fk_system_note_metadata_id_convert_to_bigint'
+
+  def up
+    return unless com_or_dev_or_test_but_not_jh?
+
+    prepare_async_foreign_key_validation TABLE_NAME, COLUMN, name: FK_NAME
+  end
+
+  def down
+    return unless com_or_dev_or_test_but_not_jh?
+
+    unprepare_async_foreign_key_validation TABLE_NAME, COLUMN, name: FK_NAME
+  end
+end

db/schema_migrations/20240117055908

+5b627596a1f7113560661563b1064fd57f6cfcf7dc59dd659156f0498a9b0b48
\ No newline at end of file

db/schema_migrations/20240117070931

+9d9a1ea947c9649bdd21a645136f89387c1035c6e8a6dea1866be65db40f77fa
\ No newline at end of file

db/schema_migrations/20240117070946

+95181aec9fa75ae026e79e8c617dc0e7a30387580eda194022e9295944d811be
\ No newline at end of file

db/structure.sql

@@ -41090,6 +41090,9 @@ ALTER TABLE ONLY integrations
 ALTER TABLE ONLY merge_requests
     ADD CONSTRAINT fk_source_project FOREIGN KEY (source_project_id) REFERENCES projects(id) ON DELETE SET NULL;
+ALTER TABLE ONLY resource_link_events
+    ADD CONSTRAINT fk_system_note_metadata_id_convert_to_bigint FOREIGN KEY (system_note_metadata_id) REFERENCES system_note_metadata(id_convert_to_bigint) ON DELETE CASCADE NOT VALID;
+
 ALTER TABLE ONLY timelogs
     ADD CONSTRAINT fk_timelogs_issues_issue_id FOREIGN KEY (issue_id) REFERENCES issues(id) ON DELETE CASCADE;