def do_filter(self, engine_slug, queryset, search_text):
        model = queryset.model
        content_type = ContentType.objects.get_for_model(model)
        pk = model._meta.pk
        if has_int_pk(model):
            ref_name = "object_id_int"
        else:
            ref_name = "object_id"
        return queryset.extra(
            tables = ("watson_searchentry",),
            where = (
                "watson_searchentry.engine_slug = %s",
                "watson_searchentry.search_tsv @@ to_tsquery('{search_config}', %s)".format(
                    search_config = self.search_config
                ),
                "watson_searchentry.{ref_name} = {table_name}.{pk_name}".format(
                    ref_name = ref_name,
                    table_name = connection.ops.quote_name(model._meta.db_table),
                    pk_name = connection.ops.quote_name(pk.db_column or pk.attname),
                ),
                "watson_searchentry.content_type_id = %s"
            ),
            params = (engine_slug, self.escape_postgres_query(search_text), content_type.id),
        )
Performs the full text filter.
dataset/ETHPy150Open etianen/django-watson/src/watson/backends.py/PostgresSearchBackend.do_filter