Remove duplicated index from merge_request_assignees

Removes index_merge_request_assignees_on_merge_request_id
as is already covered by another index

Changelog: changed

db/post_migrate/20231109183438_drop_merge_request_assignees_on_merge_request_id_index.rb

+# frozen_string_literal: true
+
+class DropMergeRequestAssigneesOnMergeRequestIdIndex < Gitlab::Database::Migration[2.2]
+  disable_ddl_transaction!
+
+  milestone '16.6'
+
+  INDEX_NAME = 'index_merge_request_assignees_on_merge_request_id'
+  TABLE_NAME = :merge_request_assignees
+
+  def up
+    # Duplicated index. This index is covered by +index_merge_request_assignees_on_merge_request_id_and_user_id+
+    remove_concurrent_index_by_name TABLE_NAME, INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index TABLE_NAME, :merge_request_id, name: INDEX_NAME
+  end
+end

db/schema_migrations/20231109183438

+87a41f56368f4211291dc6022af91a2168c389b426a1d615321cf0f36bd2c801
\ No newline at end of file

db/structure.sql

@@ -33208,8 +33208,6 @@ CREATE INDEX index_members_on_user_id_and_access_level_requested_at_is_null ON m
 CREATE INDEX index_members_on_user_id_created_at ON members USING btree (user_id, created_at) WHERE ((ldap = true) AND ((type)::text = 'GroupMember'::text) AND ((source_type)::text = 'Namespace'::text));
-CREATE INDEX index_merge_request_assignees_on_merge_request_id ON merge_request_assignees USING btree (merge_request_id);
-
 CREATE UNIQUE INDEX index_merge_request_assignees_on_merge_request_id_and_user_id ON merge_request_assignees USING btree (merge_request_id, user_id);
 CREATE INDEX index_merge_request_assignees_on_user_id ON merge_request_assignees USING btree (user_id);

spec/support/helpers/database/duplicate_indexes.yml

@@ -103,9 +103,6 @@ member_tasks:
 members:
   index_members_on_member_namespace_id_compound:
     - index_members_on_member_namespace_id
-merge_request_assignees:
-  index_merge_request_assignees_on_merge_request_id_and_user_id:
-    - index_merge_request_assignees_on_merge_request_id
 merge_requests:
   index_merge_requests_on_author_id_and_created_at:
     - index_merge_requests_on_author_id