[#MDEV-5122] "Commands out of sync", "Malformed packet" or client hang up on unique key violation

The problems started happening from the following revision on 10.0-base-explain-slowquerylog

revno: 3711

revision-id: psergey@askmonty.org-20131007132951-lhe4earylf5m2vmp

message:

  MDEV-3798: EXPLAIN UPDATE/DELETE

  - Add support for EXPLAIN INSERT.

and are still reproducible on the current tree:

bzr version-info

revision-id: psergey@askmonty.org-20131009090746-6zfqg47elbhnquac

revno: 3715

branch-nick: 10.0-base-explain-slowquerylog

BUILD/compile-pentium-debug-max-no-ndb

The first test case is an extract from federated.federatedx test, slightly modified to work on a single server.

drop database if exists federated;

drop table if exists test.t1;

create database federated;

create table federated.t1 (a int primary key, b varchar(64))   DEFAULT CHARSET=utf8;

create table test.t1 (a int primary key, b varchar(64))  ENGINE=FEDERATED connection='mysql://root@127.0.0.1:3306/federated/t1' DEFAULT CHARSET=utf8;

insert into test.t1 values (1,"Larry"), (2,"Curly"), (1,"Moe") on duplicate key update a=a+100;

select * from t1;

According to the federated test, the INSERT should fail with ER_DUP_KEY, but on some reason it doesn't:

MariaDB [test]> insert into test.t1 values (1,"Larry"), (2,"Curly"), (1,"Moe") on duplicate key update a=a+100;

Query OK, 3 rows affected (0.02 sec)

Records: 3  Duplicates: 0  Warnings: 0

And the following SELECT fails with "Commands out of sync":

MariaDB [test]> select * from t1;

ERROR 2014 (HY000): Received error: 2014 : Commands out of sync; you can't run this command now

The second test case is based on a fragment from rpl.rpl_sp:

drop table if exists t1;

drop function if exists fn1;

create table t1 (a int, unique(a));

delimiter |;

create function fn1(x int)

  returns int

begin

  insert into t1 values(x),(x);

  return 10;

end|

delimiter ;|

do fn1(100);

The DO command hangs. The processlist does not show any queries in the thread, but the query in the client does not finish.

If it is replaced with SELECT fn1(100), it causes an error:

MariaDB [test]> select fn1(100);

ERROR 2027 (HY000): Malformed packet

[MDEV-5122] "Commands out of sync", "Malformed packet" or client hang up on unique key violation Created: 2013-10-10 Updated: 2018-06-06 Resolved: 2013-10-11
Status:	Closed
Project:	MariaDB Server
Component/s:	None
Affects Version/s:	None
Fix Version/s:	10.0.5