Add index to partitioned web_hook_logs

- Add the index on (created_at, web_hook_id) that
is defined for web_hook_logs to the partitioned version
of the table

changelogs/unreleased/323676-add-index-on-created-at-web-hook-id-to-partitioned-web-hook-logs.yml

+---
+title: Add index on (created_at, web_hook_id) to the partitioned web_hook_logs
+merge_request: 59261
+author:
+type: other

db/migrate/20210413121101_add_created_at_web_hook_id_index_to_partitioned_web_hook_log.rb

+# frozen_string_literal: true
+
+class AddCreatedAtWebHookIdIndexToPartitionedWebHookLog < ActiveRecord::Migration[6.0]
+  include Gitlab::Database::PartitioningMigrationHelpers
+
+  DOWNTIME = false
+
+  CREATED_AT_WEB_HOOK_ID_INDEX_NAME = 'index_web_hook_logs_part_on_created_at_and_web_hook_id'
+
+  disable_ddl_transaction!
+
+  def up
+    add_concurrent_partitioned_index :web_hook_logs_part_0c5294f417,
+      [:created_at, :web_hook_id],
+      name: CREATED_AT_WEB_HOOK_ID_INDEX_NAME
+  end
+
+  def down
+    remove_concurrent_partitioned_index_by_name :web_hook_logs_part_0c5294f417, CREATED_AT_WEB_HOOK_ID_INDEX_NAME
+  end
+end

db/schema_migrations/20210413121101

+fe98a617ac8bacf270425c1e9b9b60aee1c3c0e47d5c915fe122cb99c1c1c822
\ No newline at end of file

db/structure.sql

@@ -24260,6 +24260,8 @@ CREATE INDEX index_web_hook_logs_on_created_at_and_web_hook_id ON web_hook_logs
 
 CREATE INDEX index_web_hook_logs_on_web_hook_id ON web_hook_logs USING btree (web_hook_id);
 
+CREATE INDEX index_web_hook_logs_part_on_created_at_and_web_hook_id ON ONLY web_hook_logs_part_0c5294f417 USING btree (created_at, web_hook_id);
+
 CREATE INDEX index_web_hook_logs_part_on_web_hook_id ON ONLY web_hook_logs_part_0c5294f417 USING btree (web_hook_id);
 
 CREATE INDEX index_web_hooks_on_group_id ON web_hooks USING btree (group_id) WHERE ((type)::text = 'GroupHook'::text);