MDEV-24532 Table corruption ER_NO_SUCH_TABLE_IN_ENGINE .. on table with foreign key

When doing a truncate on an Innodb under lock tables, InnoDB would rename
the old table to #sql-... and recreate a new 't1' table. The table lock
would still be on the #sql-table.

When doing ALTER TABLE, Innodb would do the changes on the #sql table
(which would disappear on close).
When the SQL layer, as part of inline alter table, would close the
original t1 table (#sql in InnoDB) and then reopen the t1 table, Innodb
would notice that this does not match it's own (old) t1 table and
generate an error.

Fixed by adding code in truncate table that if we are under lock tables
and truncating an InnoDB table, we would close, reopen and lock the
table after truncate. This will remove the #sql table and ensure that
lock tables is using the new empty table.

Reviewer: Marko Mäkelä

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

@@ -57,3 +57,14 @@ disconnect dml;
 connection default;
 SET DEBUG_SYNC = RESET;
 DROP TABLE child, parent;
+#
+# MDEV-24532 Table corruption ER_NO_SUCH_TABLE_IN_ENGINE or
+# ER_CRASHED_ON_USAGE after ALTER on table with foreign key
+#
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a)) ENGINE=InnoDB;
+ALTER TABLE t1 ADD FOREIGN KEY (b) REFERENCES t1 (a) ON UPDATE CASCADE;
+LOCK TABLE t1 WRITE;
+TRUNCATE TABLE t1;
+ALTER TABLE t1 ADD c INT;
+UNLOCK TABLES;
+DROP TABLE t1;

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

@@ -67,3 +67,16 @@ connection default;
 SET DEBUG_SYNC = RESET;
 
 DROP TABLE child, parent;
+
+--echo #
+--echo # MDEV-24532 Table corruption ER_NO_SUCH_TABLE_IN_ENGINE or
+--echo # ER_CRASHED_ON_USAGE after ALTER on table with foreign key
+--echo #
+
+CREATE TABLE t1 (a INT, b INT, PRIMARY KEY (a)) ENGINE=InnoDB;
+ALTER TABLE t1 ADD FOREIGN KEY (b) REFERENCES t1 (a) ON UPDATE CASCADE;
+LOCK TABLE t1 WRITE;
+TRUNCATE TABLE t1;
+ALTER TABLE t1 ADD c INT;
+UNLOCK TABLES;
+DROP TABLE t1;

sql/handler.h

@@ -1419,6 +1419,12 @@ handlerton *ha_default_tmp_handlerton(THD *thd);
 // MySQL compatibility. Unused.
 #define HTON_SUPPORTS_FOREIGN_KEYS   (1 << 0) //Foreign key constraint supported.
 
+/*
+  Table requires and close and reopen after truncate
+  If the handler has HTON_CAN_RECREATE, this flag is not used
+*/
+#define HTON_REQUIRES_CLOSE_AFTER_TRUNCATE (1 << 18)
+
 class Ha_trx_info;
 
 struct THD_TRANS

sql/sql_truncate.cc

@@ -439,6 +439,15 @@ bool Sql_cmd_truncate_table::truncate_table(THD *thd, TABLE_LIST *table_ref)
       */
       error= handler_truncate(thd, table_ref, FALSE);
 
+      if (error == TRUNCATE_OK && thd->locked_tables_mode &&
+          (table_ref->table->file->ht->flags &
+           HTON_REQUIRES_CLOSE_AFTER_TRUNCATE))
+      {
+        thd->locked_tables_list.mark_table_for_reopen(thd, table_ref->table);
+        if (unlikely(thd->locked_tables_list.reopen_tables(thd, true)))
+          thd->locked_tables_list.unlink_all_closed_tables(thd, NULL, 0);
+      }
+
       /*
         All effects of a TRUNCATE TABLE operation are committed even if
         truncation fails in the case of non transactional tables. Thus, the

storage/innobase/handler/ha_innodb.cc

@@ -3702,7 +3702,8 @@ innobase_init(
 	innobase_hton->flush_logs = innobase_flush_logs;
 	innobase_hton->show_status = innobase_show_status;
 	innobase_hton->flags =
-		HTON_SUPPORTS_EXTENDED_KEYS | HTON_SUPPORTS_FOREIGN_KEYS;
+		HTON_SUPPORTS_EXTENDED_KEYS | HTON_SUPPORTS_FOREIGN_KEYS |
+		HTON_REQUIRES_CLOSE_AFTER_TRUNCATE;
 
 #ifdef WITH_WSREP
         innobase_hton->abort_transaction=wsrep_abort_transaction;