too small max_statement_time is ignored

$ mysql-test/mtr main.func_json_notembedded

Logging: /home/dan/repos/mariadb-server-10.6/mysql-test/mariadb-test-run.pl  main.func_json_notembedded

VS config: 

vardir: /home/dan/repos/build-mariadb-server-10.6/mysql-test/var

Checking leftover processes...

Removing old var directory...

Creating var directory '/home/dan/repos/build-mariadb-server-10.6/mysql-test/var'...

Checking supported features...

MariaDB Version 10.6.8-MariaDB

 - SSL connections supported

 - binaries built with wsrep patch

Collecting tests...

Installing system database...

==============================================================================

TEST                                      RESULT   TIME (ms) or COMMENT

--------------------------------------------------------------------------

worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 16000..16019

main.func_json_notembedded               [ fail ]

        Test ended at 2022-04-07 13:52:38

CURRENT_TEST: main.func_json_notembedded

mysqltest: At line 38: query 'select json_merge_patch(@obj, @obj)' failed with wrong errno <Unknown> (2013): 'Lost connection to server during query', instead of ER_STATEMENT_TIMEOUT (1969)...

The result from queries just before the failure was:

< snip >

select sleep(t);

execute immediate 'kill connection ?' using c;

end|

connection default;

set @timeout= 20;

call kill_soon(@timeout, THE_OTHER_CONNECTION);;

connection u;

#

# MDEV-24909 JSON functions don't respect KILL QUERY / max_statement_time limit

#

set group_concat_max_len= 4294967295;

set @obj=concat_ws('','{', repeat('"a":"b",', 125000), '"c":"d"}');

set @arr=concat_ws('','[', repeat('1234567,', 125000), '2345678]');

select length(@obj), length(@arr);

length(@obj)	length(@arr)

1000009	1000009

set max_statement_time=0.0001;

set max_statement_time=0.0000001;

select json_merge_patch(@obj, @obj);

The servers were restarted 0 times

Spent 0.000 of 36 seconds executing testcases

source include/have_profiling.inc;

source include/not_embedded.inc;

set global max_allowed_packet=1073741824;

connect u,localhost,root;

delimiter |;

create procedure kill_soon(IN t INT, IN C INT)

begin

  select sleep(t);

  execute immediate 'kill connection ?' using c;

end|

delimiter ;|

--let $con=`SELECT CONNECTION_ID()`

connection default;

set @timeout= 20;

--replace_result $con THE_OTHER_CONNECTION

--send_eval call kill_soon(@timeout, $con);

connection u;

--echo #

--echo # MDEV-24909 JSON functions don't respect KILL QUERY / max_statement_time limit

--echo #

set group_concat_max_len= 4294967295;

set @obj=concat_ws('','{', repeat('"a":"b",', 125000), '"c":"d"}');

set @arr=concat_ws('','[', repeat('1234567,', 125000), '2345678]');

select length(@obj), length(@arr);

set max_statement_time=0.0001;

set max_statement_time=0.0000001;

--error ER_STATEMENT_TIMEOUT

select json_merge_patch(@obj, @obj);

enable_abort_on_error;

disconnect u;

connection default;

--replace_result $con THE_OTHER_CONNECTION

--error ER_NO_SUCH_THREAD

reap;

drop procedure kill_soon;

set global max_allowed_packet=default;