Streaming insert fails silently on 8.0

[aquarapid]

Setup local unsharded example with 7.0:

$ sh -x 101_initial_cluster.sh
.
.

Now, observe the behavior of trying to do a streaming (OLAP mode) insert:

$ mysql -c -h 127.0.0.1 -P 15306 -u root -A
Welcome to the MySQL monitor.  Commands end with ; or \g.
.
.

mysql> use commerce;
Database changed
mysql> select * from product;
Empty set (0.00 sec)

mysql> set workload=olap;                                                                            
Query OK, 0 rows affected (0.00 sec)

mysql> select * from product;
Empty set (0.00 sec)

mysql> insert into product (sku,description, price) values ("12345678","1234",100);                     
ERROR 1105 (HY000): vtgate: http://localhost:15001/: query "insert into product(sku, description, price) values (:vtg1, :vtg2, :vtg3)" cannot be used for streaming

All good so far; inserts are not supported in OLAP/streaming mode. However, on 8.0 (approximately, current master d6c9ddf), the insert will "succeed"; and then the client will get disconnected, but that only becomes apparent on the next command issued by the client:

$ mysql -c -h 127.0.0.1 -P 15306 -u root -A
Welcome to the MySQL monitor.  Commands end with ; or \g.
.
.

mysql> use commerce;
Database changed

mysql> set workload=olap;
Query OK, 0 rows affected (0.01 sec)

mysql> select @@workload;
+------------+
| @@workload |
+------------+
| OLAP       |
+------------+
1 row in set (0.00 sec)

mysql> insert into product (sku,description, price) values ("12345","1234",100);
Query OK, 0 rows affected (0.00 sec)

mysql> select * from product;
ERROR 2013 (HY000): Lost connection to MySQL server during query

• Note the 0 rows affected from the insert.
• From the vtgate logs:

E1023 14:28:17.958999   30917 vtgate.go:454] StreamExecute: query "insert into product(sku, description, price) values (:vtg1, :vtg2, :vtg3)" cannot be used for streaming, request: map[BindVariables:map[vtg1:type:VARBINARY value:"12345"  vtg2:type:VARBINARY value:"1234"  vtg3:type:INT64 value:"100" ] Session:autocommit:true target_string:"commerce" options:<included_fields:ALL workload:OLAP > row_count:-1 Sql:insert into product (sku,description, price) values ("12345","1234",100)]
E1023 14:28:17.959161   30917 conn.go:1276] Error in the middle of a stream to client 9 (127.0.0.1:52938): vtgate: http://localhost:15001/: query "insert into product(sku, description, price) values (:vtg1, :vtg2, :vtg3)" cannot be used for streaming (errno 1105) (sqlstate HY000)