MDEV-14632 Assertion `!((new_col->prtype ^ col->prtype) & ~256U)' failed in row_log_table_apply_convert_mrec

SQL: add exclusive lock to ADD/DROP SYSTEM VERSIONING clauses This is needed because Online DDL is not working yet for such queries.

Author: kevgs

sql/handler.cc

@@ -7098,6 +7098,18 @@ bool Vers_parse_info::fix_alter_info(THD *thd, Alter_info *alter_info,
  if (!need_check() && !share->versioned)
  return false;
 
+ if (with_system_versioning || without_system_versioning)
+ {
+ // Disable Online DDL which is not implemented yet for ADD/DROP SYSTEM VERSIONING.
+ if (thd->mdl_context.upgrade_shared_lock(table->mdl_ticket, MDL_EXCLUSIVE,
+ thd->variables.lock_wait_timeout))
+ {
+ my_error(ER_LOCK_WAIT_TIMEOUT, MYF(0));
+ return true;
+ }
+ alter_info->requested_lock= Alter_info::ALTER_TABLE_LOCK_EXCLUSIVE;
+ }
+
  if (with_system_versioning && table->versioned())
  {
  my_error(ER_VERS_ALREADY_VERSIONED, MYF(0), table_name);