How to find corrupted records in postgresql

pg_corrupted_data.sql

#Find the corrupted rows

DO $$
declare
    curid INT := 0;
    vcontent TEXT;
    badid INT;
begin
  FOR badid IN SELECT id FROM events LOOP
      curid = curid + 1;
      if curid % 100000 = 0 then
          raise notice '% rows inspected', curid;
      end if;
      begin
          SELECT message
          INTO vcontent
          FROM events where id = badid;
          vcontent := substr(vcontent,100,2000);
      exception
          when others then
              raise notice 'data for message % is corrupt', badid;
              continue;
      end;
  end loop;
end;
$$;