create table cftest (
  id int primary key,
  pstr string,
  data string,
  FAMILY prim (id, pstr),
  FAMILY df (data)
);

insert into cftest (id, pstr, data)
select
  g,
  'hello-' || g::string,
  REPEAT('SQL', 5000)
from generate_series(1, 10000) as g;

set cluster setting changefeed.memory.per_changefeed_limit = '1MiB'; -- set this low to make it easier to hit the limit

CREATE CHANGEFEED FOR TABLE cftest family prim INTO 'null:' with initial_scan='no', diff; 
-- diff is not required to break it, but also makes it easier to hit the limt, as prev values' allocs are also leaked

update cftest set data = REPEAT('SQL2', 5000) where true;