MDEV-25051 Race condition between persistent statistics and RENAME TABLE or TRUNCATE

innobase_rename_table(): Invoke dict_stats_wait_bg_to_stop_using_table()
to ensure that dict_stats_update() cannot be accessing the table name
that we will be modifying. If we are executing RENAME rather than TRUNCATE,
reset the flag at the end so that persistent statistics can be calculated
again.

The race condition was encountered with ASAN and rr.
Sorry, there is no test case, like there is for nothing related to
dict_stats_wait_bg_to_stop_using_table(). The entire code is an ugly
work-around for the failure of dict_stats_process_entry_from_recalc_pool()
to acquire MDL.

Note: It appears that an ALTER TABLE that is not rebuilding the table
will fail to reset the flag that blocks the processing of statistics.

1 files changed, 18 insertions, 14 deletions

diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index c67bf6bd607..11d8ec2b81e 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -13518,17 +13518,10 @@ innobase_drop_database(
 @param[in,out]	trx	InnoDB data dictionary transaction
 @param[in]	from	old table name
 @param[in]	to	new table name
-@param[in]	commit	whether to commit trx
-@param[in]	use_fk	whether to parse and enforce FOREIGN KEY constraints
+@param[in]	commit	whether to commit trx (and to enforce FOREIGN KEY)
 @return DB_SUCCESS or error code */
-inline
-dberr_t
-innobase_rename_table(
-	trx_t*		trx,
-	const char*	from,
-	const char*	to,
-	bool		commit,
-	bool		use_fk)
+inline dberr_t innobase_rename_table(trx_t *trx, const char *from,
+                                     const char *to, bool commit)
 {
 	dberr_t	error;
 	char	norm_to[FN_REFLEN];
@@ -13561,6 +13554,9 @@ innobase_rename_table(
 	Convert lock_wait_timeout unit from second to 250 milliseconds */
 	long int lock_wait_timeout = thd_lock_wait_timeout(trx->mysql_thd) * 4;
 	if (table != NULL) {
+		if (commit) {
+			dict_stats_wait_bg_to_stop_using_table(table, trx);
+		}
 		for (dict_index_t* index = dict_table_get_first_index(table);
 		     index != NULL;
 		     index = dict_table_get_next_index(index)) {
@@ -13574,7 +13570,9 @@ innobase_rename_table(
 				}
 			}
 		}
-		dict_table_close(table, TRUE, FALSE);
+		if (!commit) {
+			dict_table_close(table, TRUE, FALSE);
+		}
 	}
 
 	/* FTS sync is in progress. We shall timeout this operation */
@@ -13589,7 +13587,7 @@ innobase_rename_table(
 	ut_a(trx->will_lock > 0);
 
 	error = row_rename_table_for_mysql(norm_from, norm_to, trx, commit,
-					   use_fk);
+					   commit);
 
 	if (error != DB_SUCCESS) {
 		if (error == DB_TABLE_NOT_FOUND
@@ -13641,6 +13639,10 @@ innobase_rename_table(
 
 func_exit:
 	if (commit) {
+		if (table) {
+			table->stats_bg_flag &= ~BG_STAT_SHOULD_QUIT;
+			dict_table_close(table, TRUE, FALSE);
+		}
 		row_mysql_unlock_data_dictionary(trx);
 	}
 
@@ -13726,9 +13728,11 @@ int ha_innobase::truncate()
 	++trx->will_lock;
 	trx_set_dict_operation(trx, TRX_DICT_OP_TABLE);
 	row_mysql_lock_data_dictionary(trx);
+	dict_stats_wait_bg_to_stop_using_table(ib_table, trx);
+
 	int err = convert_error_code_to_mysql(
 		innobase_rename_table(trx, ib_table->name.m_name, temp_name,
-				      false, false),
+				      false),
 		ib_table->flags, m_user_thd);
 	if (err) {
 		trx_rollback_for_mysql(trx);
@@ -13811,7 +13815,7 @@ ha_innobase::rename_table(
 	++trx->will_lock;
 	trx_set_dict_operation(trx, TRX_DICT_OP_INDEX);
 
-	dberr_t	error = innobase_rename_table(trx, from, to, true, true);
+	dberr_t	error = innobase_rename_table(trx, from, to, true);
 
 	DEBUG_SYNC(thd, "after_innobase_rename_table");