Re: Extended Statistics set/restore/clear functions.

On Tue, Nov 18, 2025 at 4:52 PM Corey Huinker <corey(dot)huinker(at)gmail(dot)com> wrote:
> v15:
>
> - catches duplicate object keys cited above
> - enforces attnum ordering (ascending positive numbers followed by descending negative numbers, no zeros allowed), which means we get duplicate attnum detection for free
> - attnum validation is now done as soon as the attnum is parsed
> - tests refactored to put attnums in proper order
> - unfortunately, this means that one of the error cases from stats_import.sql (attnum = 0) is now an error rather than something that can be soft-excluded.
> - didn't enforce combinatorical completeness for dependencies because not all combinations are guaranteed to be there.
> - didn't enforce combinatorical completeness for ndistinct because I'm not convinced we should.
>

hi.

some of the switch->default, default don't have ``break``.

+ for (int i = 0; i < nitems; i++)
+ {
+ MVNDistinctItem *item = parse_state.distinct_items->elements[i].ptr_value;

exposing the ptr_value seems not a good idea, we can foreach_ptr
the attached patch using foreach_ptr.

in function pg_ndistinct_in some errsave can change to ereturn.
(I didn't do this part, though).

+ /*
+ * The attnum cannot be zero a negative number beyond the number of the
+ * possible expressions.
+ */
+ if (attnum == 0 || attnum < (0-STATS_MAX_DIMENSIONS))
+ {
+ errsave(parse->escontext,
+ errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+ errmsg("malformed pg_ndistinct: \"%s\"", parse->str),
+ errdetail("Invalid \"%s\" element: %d.",
+ PG_NDISTINCT_KEY_ATTRIBUTES, attnum));
+ return JSON_SEM_ACTION_FAILED;
+ }
This part had no coverage tests, so I added a few.

as mentioned before
+ errsave(parse->escontext,
+ errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
+ errmsg("malformed pg_ndistinct: \"%s\"", parse->str),
+ errdetail("The \"%s\" key must contain an array of at least %d "
+ "and no more than %d attributes.",
+ PG_NDISTINCT_KEY_NDISTINCT, 2, STATS_MAX_DIMENSIONS));
here PG_NDISTINCT_KEY_NDISTINCT, should be PG_NDISTINCT_KEY_ATTRIBUTES.

Please check the attached minor miscellaneous changes.

--
jian
https://www.enterprisedb.com/