Update to migration's unique key column data loss: fixing

Author: Shlomi Noach

localtests/update-pk-column/create.sql

@@ -0,0 +1,45 @@
+drop table if exists gh_ost_test;
+create table gh_ost_test (
+  id int auto_increment,
+  i int not null,
+  primary key(id)
+) auto_increment=1;
+
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+insert into gh_ost_test values (null, 13);
+
+
+drop event if exists gh_ost_test;
+delimiter ;;
+create event gh_ost_test
+  on schedule every 1 second
+  starts current_timestamp + interval 3 second
+  ends current_timestamp + interval 60 second
+  on completion not preserve
+  enable
+  do
+begin
+  update gh_ost_test set id=-2 where id=21;
+end ;;