Re: Dead code with short varlenas in toast_save_datum()

Hi all,

On Sun, Aug 3, 2025 at 8:16 PM Michael Paquier <michael@paquier.xyz> wrote:
>     if (VARATT_IS_SHORT(dval))
>     {
>         data_p = VARDATA_SHORT(dval);
>         data_todo = VARSIZE_SHORT(dval) - VARHDRSZ_SHORT;
>         toast_pointer.va_rawsize = data_todo + VARHDRSZ;    /* as if not short */
>         toast_pointer.va_extinfo = data_todo;
>     }
>
> Coverage link:
> https://coverage.postgresql.org/src/backend/access/common/toast_internals.c.gcov.html
>

This code path is currently not covered by tests. It can be exercised
with the following SQL pattern

CREATE TABLE temp_tbl (a text, b text);
ALTER TABLE temp_tbl SET (toast_tuple_target = 128);
ALTER TABLE temp_tbl ALTER COLUMN a SET STORAGE EXTERNAL;
ALTER TABLE temp_tbl ALTER COLUMN b SET STORAGE EXTERNAL;
INSERT INTO temp_tbl values(repeat('a', 4000), repeat('a', 120));

--
Nikhil Veldanda