ActiveRecord Row Lock Test Output

row_lock_test_output.txt

Current ActiveRecord code:

Selector Thread reports shared record exists
Thread 1    (0.8ms)  BEGIN
Thread 1 running before_destroy callback
Thread 2    (0.6ms)  BEGIN
Thread 2 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Thread 2 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Thread 2 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Thread 2 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Thread 2 running before_destroy callback
Selector Thread reports shared record exists
Thread 1   SQL (26.3ms)  DELETE FROM "my_models" WHERE "my_models"."id" = $1  [["id", 43]]
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 2   SQL (4934.5ms)  DELETE FROM "my_models" WHERE "my_models"."id" = $1  [["id", 43]]
Thread 2 running after_destroy callback
Thread 1    (1.5ms)  COMMIT
Selector Thread reports shared record deleted
Thread 2 running after_destroy callback
Selector Thread reports shared record deleted
Thread 2 running after_destroy callback
Selector Thread reports shared record deleted
Thread 2 running after_destroy callback
Selector Thread reports shared record deleted
Thread 2 running after_destroy callback
Selector Thread reports shared record deleted
Thread 2    (0.7ms)  COMMIT
Selector Thread reports shared record deleted


Patched ActiveRecord code:

Selector Thread reports shared record exists
Thread 1    (0.7ms)  BEGIN
Thread 1    (1.1ms)  SELECT id FROM "my_models" WHERE "my_models"."id" = 40 FOR UPDATE
Thread 1 SELECT FOR UPDATE did find row
Thread 1 running before_destroy callback
Thread 2    (0.6ms)  BEGIN
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Selector Thread reports shared record exists
Thread 1 running before_destroy callback
Selector Thread reports shared record exists
Thread 1   SQL (37.1ms)  DELETE FROM "my_models" WHERE "my_models"."id" = $1  [["id", 40]]
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1 running after_destroy callback
Selector Thread reports shared record exists
Thread 1    (1.2ms)  COMMIT
Thread 2    (9953.0ms)  SELECT id FROM "my_models" WHERE "my_models"."id" = 40 FOR UPDATE
Thread 2 SELECT FOR UPDATE does not find row
Thread 2   SQL (1.1ms)  DELETE FROM "my_models" WHERE "my_models"."id" = $1  [["id", 40]]
Thread 2    (0.3ms)  COMMIT
Selector Thread reports shared record deleted