Remove `project_relation_exports` index

This is a duplicated index.

Changelog: performance

db/post_migrate/20231122130721_drop_index_project_relation_exports_on_project_export_job_id.rb

+# frozen_string_literal: true
+
+class DropIndexProjectRelationExportsOnProjectExportJobId < Gitlab::Database::Migration[2.2]
+  disable_ddl_transaction!
+
+  milestone '16.7'
+
+  INDEX_NAME = :index_project_relation_exports_on_project_export_job_id
+  TABLE_NAME = :project_relation_exports
+
+  def up
+    remove_concurrent_index_by_name TABLE_NAME, INDEX_NAME
+  end
+
+  def down
+    add_concurrent_index TABLE_NAME, :project_export_job_id, name: INDEX_NAME
+  end
+end

db/schema_migrations/20231122130721

+7aac0b2b22e877663ed260084891b64eda07ca4c73b23760474c1e5520f54292
\ No newline at end of file

db/structure.sql

@@ -33973,8 +33973,6 @@ CREATE INDEX index_project_pages_metadata_on_project_id_and_deployed_is_true ON
 CREATE INDEX index_project_relation_export_upload_id ON project_relation_export_uploads USING btree (project_relation_export_id);
-CREATE INDEX index_project_relation_exports_on_project_export_job_id ON project_relation_exports USING btree (project_export_job_id);
-
 CREATE UNIQUE INDEX index_project_repositories_on_disk_path ON project_repositories USING btree (disk_path);
 CREATE UNIQUE INDEX index_project_repositories_on_project_id ON project_repositories USING btree (project_id);

spec/support/helpers/database/duplicate_indexes.yml

@@ -148,9 +148,6 @@ pm_package_versions:
 project_compliance_standards_adherence:
   u_project_compliance_standards_adherence_for_reporting:
     - index_project_compliance_standards_adherence_on_project_id
-project_relation_exports:
-  index_project_export_job_relation:
-    - index_project_relation_exports_on_project_export_job_id
 project_repositories:
   index_project_repositories_on_shard_id_and_project_id:
     - index_project_repositories_on_shard_id