ER_GET_ERRNO upon online alter with concurrent DML on CONNECT table

--source include/have_debug_sync.inc

install soname 'ha_connect';

create table t (a int) engine=Connect table_type=DOS;

insert into t values (1),(2);

--send set debug_sync= 'now wait_for go_dml'

--connect (con1,localhost,root,,)

set debug_sync='alter_table_online_progress signal go_dml wait_for go_alter';

--send alter table t add b int, algorithm=copy, lock=none

--connection default

--reap

delete from t where a = 2;

set debug_sync= 'now signal go_alter';

--connection con1

--reap

select * from t;

# Cleanup

drop table t;

uninstall soname 'ha_connect';

At line 19: query 'reap' failed: ER_GET_ERRNO (1030): Got error 174 "Fatal error during initialization of handler" from storage engine CONNECT