Follow-up fix to MDEV-13201 Assertion srv_undo_sources || ... failed on shutdown during DDL operation

Introduce the debug flag trx_t::persistent_stats to suppress the
assertion for the updates of persistent statistics during fast
shutdown.

dict_stats_exec_sql(): Do execute the statement even though shutdown
has been initiated.

mysql-test/suite/innodb/r/truncate_restart.result

@@ -1,6 +1,5 @@
-call mtr.add_suppression("InnoDB: Cannot save table statistics for table `test`\\.`t1`: Persistent statistics do not exist");
 SET GLOBAL innodb_stats_persistent= ON;
-CREATE TABLE t1 (t TEXT) ENGINE=InnoDB;
+CREATE TABLE t1 (t TEXT) ENGINE=InnoDB STATS_PERSISTENT=1;
 connect  con1,localhost,root,,test;
 SET DEBUG_SYNC='ib_trunc_table_trunc_completing SIGNAL committed WAIT_FOR ever';
 TRUNCATE TABLE t1;

mysql-test/suite/innodb/t/truncate_restart.test

@@ -2,10 +2,8 @@
 --source include/have_debug.inc
 --source include/have_debug_sync.inc
 
-call mtr.add_suppression("InnoDB: Cannot save table statistics for table `test`\\.`t1`: Persistent statistics do not exist");
-
 SET GLOBAL innodb_stats_persistent= ON;
-CREATE TABLE t1 (t TEXT) ENGINE=InnoDB;
+CREATE TABLE t1 (t TEXT) ENGINE=InnoDB STATS_PERSISTENT=1;
 --connect (con1,localhost,root,,test)
 SET DEBUG_SYNC='ib_trunc_table_trunc_completing SIGNAL committed WAIT_FOR ever';
 --send

storage/innobase/btr/btr0defragment.cc

@@ -831,6 +831,7 @@ DECLARE_THREAD(btr_defragment_thread)(void*)
 			mtr_commit(&mtr);
 			/* Reaching the end of the index. */
 			dict_stats_empty_defrag_stats(index);
+			ut_d(trx->persistent_stats = true);
 			++trx->will_lock;
 			dberr_t err = dict_stats_save_defrag_stats(index, trx);
 			if (err == DB_SUCCESS) {
@@ -849,6 +850,7 @@ DECLARE_THREAD(btr_defragment_thread)(void*)
 				trx_commit_for_mysql(trx);
 			}
 
+			ut_d(trx->persistent_stats = false);
 			btr_defragment_remove_item(item);
 		}
 	}

storage/innobase/dict/dict0stats.cc

@@ -287,14 +287,6 @@ dict_stats_exec_sql(
 {
 	dberr_t	err;
 
-	extern bool dict_stats_start_shutdown;
-
-	if (dict_stats_start_shutdown
-	    || !dict_stats_persistent_storage_check(true)) {
-		pars_info_free(pinfo);
-		return(DB_STATS_DO_NOT_EXIST);
-	}
-
 	err = que_eval_sql(pinfo, sql, FALSE, trx); /* pinfo is freed here */
 
 	DBUG_EXECUTE_IF("stats_index_error",
@@ -2276,6 +2268,8 @@ dict_stats_save_index_stat(
 	char		db_utf8[MAX_DB_UTF8_LEN];
 	char		table_utf8[MAX_TABLE_UTF8_LEN];
 
+	ut_ad(trx->persistent_stats || trx->in_mysql_trx_list);
+
 	dict_fs2utf8(index->table->name.m_name, db_utf8, sizeof(db_utf8),
 		     table_utf8, sizeof(table_utf8));
 
@@ -2401,6 +2395,8 @@ dict_stats_save(
 	char		db_utf8[MAX_DB_UTF8_LEN];
 	char		table_utf8[MAX_TABLE_UTF8_LEN];
 
+	ut_ad(trx->persistent_stats || trx->in_mysql_trx_list);
+
 	if (table_orig->is_readable()) {
 	} else {
 		return (dict_stats_report_error(table_orig));

storage/innobase/dict/dict0stats_bg.cc

@@ -444,6 +444,7 @@ DECLARE_THREAD(dict_stats_thread)(void*)
 #endif /* UNIV_PFS_THREAD */
 
 	trx_t* trx = trx_allocate_for_background();
+	ut_d(trx->persistent_stats = true);
 
 	while (!dict_stats_start_shutdown) {
 
@@ -476,6 +477,7 @@ DECLARE_THREAD(dict_stats_thread)(void*)
 		os_event_reset(dict_stats_event);
 	}
 
+	ut_d(trx->persistent_stats = false);
 	trx_free_for_background(trx);
 	srv_dict_stats_thread_active = false;
 

storage/innobase/handler/ha_innodb.cc

@@ -6468,9 +6468,12 @@ no_such_table:
 		if (alloc) {
 			trx = trx_allocate_for_background();
 		}
+		ut_ad(!trx->persistent_stats);
+		ut_d(trx->persistent_stats = true);
 		++trx->will_lock;
 		dict_stats_init(ib_table, trx);
 		innobase_commit_low(trx);
+		ut_d(trx->persistent_stats = false);
 		if (alloc) {
 			trx_free_for_background(trx);
 		}
@@ -14592,6 +14595,7 @@ ha_innobase::info_low(
 			on the mysql.innodb_table_stats,
 			mysql.innodb_index_stats tables. */
 			trx_t* trx = trx_allocate_for_background();
+			ut_d(trx->persistent_stats = true);
 			++trx->will_lock;
 			ret = dict_stats_update(ib_table, opt, trx);
 
@@ -14604,6 +14608,7 @@ ha_innobase::info_low(
 				trx_commit_for_mysql(trx);
 			}
 
+			ut_d(trx->persistent_stats = false);
 			trx_free_for_background(trx);
 
 			if (ret != DB_SUCCESS) {

storage/innobase/include/trx0trx.h

@@ -1123,6 +1123,9 @@ struct trx_t {
 			mysql_trx_list;	/*!< list of transactions created for
 					MySQL; protected by trx_sys->mutex */
 #ifdef UNIV_DEBUG
+	/** whether this transaction is updating persistent statistics
+	(used for silencing a debug assertion at shutdown) */
+	bool		persistent_stats;
 	bool		in_mysql_trx_list;
 					/*!< true if in
 					trx_sys->mysql_trx_list */

storage/innobase/trx/trx0purge.cc

@@ -301,7 +301,8 @@ trx_purge_add_update_undo_to_history(
 		  && purge_sys->state == PURGE_STATE_INIT)
 	      || (srv_force_recovery >= SRV_FORCE_NO_BACKGROUND
 		  && purge_sys->state == PURGE_STATE_DISABLED)
-	      || ((trx->undo_no == 0 || trx->in_mysql_trx_list)
+	      || ((trx->undo_no == 0 || trx->in_mysql_trx_list
+		   || trx->persistent_stats)
 		  && srv_fast_shutdown));
 
 	/* Add the log as the first in the history list */

storage/innobase/trx/trx0trx.cc

@@ -553,6 +553,7 @@ trx_validate_state_before_free(trx_t* trx)
 	ut_ad(!trx->declared_to_be_inside_innodb);
 	ut_ad(!trx->n_mysql_tables_in_use);
 	ut_ad(!trx->mysql_n_tables_locked);
+	ut_ad(!trx->persistent_stats);
 
 	if (trx->declared_to_be_inside_innodb) {