connect con1, localhost,root;
disconnect con1;
connect con2, localhost,root;
connection con2;
connection default;
SET @orig_debug=@@debug_dbug;
SET GLOBAL DEBUG_DBUG='+d,thread_id_overflow';
connect con3, localhost,root;
connection con3;
SELECT CONNECTION_ID();
CONNECTION_ID()
4294967294
connection default;
SET GLOBAL DEBUG_DBUG=@orig_debug;
connect con4, localhost,root;
connection con4;
select IF(connection_id() - max_id = 1,'Good','Bad') as result;
result
Good
disconnect con4;
disconnect con3;
disconnect con2;
connection default;