Reduce flakiness in update-pk test

Author: ggilder

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

@@ -9,19 +9,42 @@ insert into gh_ost_test (email) values ('alice@example.com');
 insert into gh_ost_test (email) values ('bob@example.com');
 insert into gh_ost_test (email) values ('charlie@example.com');
 
+-- Add more rows to extend row copy duration
+-- With chunk-size=10, 50 rows will take ~5 chunks giving the event time to detect and fire
+insert into gh_ost_test (email) values
+  ('user4@example.com'), ('user5@example.com'), ('user6@example.com'),
+  ('user7@example.com'), ('user8@example.com'), ('user9@example.com'),
+  ('user10@example.com'), ('user11@example.com'), ('user12@example.com'),
+  ('user13@example.com'), ('user14@example.com'), ('user15@example.com'),
+  ('user16@example.com'), ('user17@example.com'), ('user18@example.com'),
+  ('user19@example.com'), ('user20@example.com'), ('user21@example.com'),
+  ('user22@example.com'), ('user23@example.com'), ('user24@example.com'),
+  ('user25@example.com'), ('user26@example.com'), ('user27@example.com'),
+  ('user28@example.com'), ('user29@example.com'), ('user30@example.com'),
+  ('user31@example.com'), ('user32@example.com'), ('user33@example.com'),
+  ('user34@example.com'), ('user35@example.com'), ('user36@example.com'),
+  ('user37@example.com'), ('user38@example.com'), ('user39@example.com'),
+  ('user40@example.com'), ('user41@example.com'), ('user42@example.com'),
+  ('user43@example.com'), ('user44@example.com'), ('user45@example.com'),
+  ('user46@example.com'), ('user47@example.com'), ('user48@example.com'),
+  ('user49@example.com'), ('user50@example.com');
+
 drop event if exists gh_ost_test;
 delimiter ;;
 create event gh_ost_test
   on schedule every 1 second
-  starts current_timestamp + interval 3 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 ensures this fires during binlog apply phase, not bulk copy
-  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 ;;