Reduce flakiness pt. 2

Author: ggilder

localtests/panic-on-warnings-update-pk-with-duplicate-on-new-unique-index/create.sql

@@ -13,16 +13,18 @@ drop event if exists gh_ost_test;
 delimiter ;;
 create event gh_ost_test
   on schedule every 1 second
-  starts current_timestamp + interval 6 second
+  starts current_timestamp
   ends current_timestamp + interval 60 second
   on completion not preserve
   enable
   do
 begin
-  -- This UPDATE modifies the primary key, so it will be converted to DELETE + INSERT
-  -- The INSERT will attempt to insert email='alice@example.com' (duplicate)
-  -- which violates the new unique index being added by the migration
-  -- Delay of 6s ensures this fires after row copy starts (throttle delays until 5s)
-  -- but before migration completes, so duplicate is caught during DML event application
-  update gh_ost_test set id=10, email='alice@example.com' where id=2;
+  -- Poll for row copy to start by checking if alice has been copied to ghost table
+  -- Once row copy has started, fire the UPDATE that creates a duplicate
+  if exists (select 1 from test._gh_ost_test_gho where email = 'alice@example.com') then
+    -- This UPDATE modifies the primary key, so it will be converted to DELETE + INSERT
+    -- The INSERT will attempt to insert email='alice@example.com' (duplicate)
+    -- which violates the new unique index being added by the migration
+    update gh_ost_test set id=10, email='alice@example.com' where id=2;
+  end if;
 end ;;