PostgreSQL: How to get around ts_vector size limits?

Question

I am creating a search inside a Rails application using pg_search gem. However, one of the tables has a field of type Textdatatype, in which the content is slightly larger than usual.

Now that I need to adjust tsvector columnfor the columns Text, I come across some restrictions that are related to the size of the text field and the size of the tsvector.

ERROR: string is too long for tsvector (5068741 bytes, max 1048575 bytes)

Is there a way to define a condition for skipping large fields Textwhen creating a tsvector column in a trigger SQLto do something like this:

pseudo code:

execute(<<-TRIGGERSQL)
CREATE OR REPLACE FUNCTION public.essays_before_insert_update_row_tr()
 RETURNS trigger
 LANGUAGE plpgsql
AS $function$
BEGIN
    If (SELECT LEN(body_text) FROM essays) <= 1048575
      new.tsv_body_text := to_tsvector('pg_catalog.english', coalesce(new.body_text,''));
      RETURN NEW;
    End
END;
$function$
  TRIGGERSQL

  # no candidate create_trigger statement could be found, creating an adapter-specific one
  execute("CREATE TRIGGER essays_before_insert_update_row_tr BEFORE INSERT OR UPDATE ON \"essays\" FOR EACH ROW EXECUTE PROCEDURE essays_before_insert_update_row_tr()")

which I found unanswered:

Postgresql - convert text to ts_vector