Re: [PATCH] Add row estimate tests for unnest() and integer generate_series()

Hi all,

On Tue, Sep 15, 2026 at 3:20 PM shihao zhong <zhong950419(at)gmail(dot)com> wrote:
>
> Hi hackers,
>
> The support functions for unnest() and the integer variants of
> generate_series() have no regression tests for their row estimates.
>
> They were added in v12, before planner_est.sql existed. The numeric
> and timestamp variants got tests together with their support
> functions.
>
> The attached patch adds sections for both, following the existing
> style. Test changes only.
>

Thank you for the patch. I reviewed the patch and tested it on my
local PostgreSQL tree. The patch applies cleanly and is limited to
regression test changes in planner_est.sql and planner_est.out. I ran
the focused regression test: # All 245 tests passed. I manually
verified the added cases for both generate_series() and unnest(). The
row estimates matched the expected behavior for normal, stepped,
descending, bigint, and large-range generate_series() cases. The empty
and NULL cases correctly show an estimate of 1 after clamping, and the
zero-step case falls back to the default estimate and raises the
expected error during execution. For unnest(), I verified constant and
multidimensional arrays, empty/NULL arrays, ArrayExpr,
statistics-based estimation, and the default estimate when
array-column statistics are unavailable. The observed results matched
the expected regression output. I did not find any functional issues
with the patch.
One minor comment clarification could be considered: the comment for
the constant NULL generate_series() case says "-- Ensure a constant
NULL argument estimates no rows", while the final planner estimate is
1 due to clamping. This could perhaps be worded consistently with the
corresponding unnest() test.
Apart from this minor wording point, the patch looks good to me.

Regards,
Solai