Re: Add PRODUCT() aggregate function

Hello,

On Sun, Sep 13, 2026 at 12:23 PM Vaibhav Dalvi <
vaibhav(dot)dalvi(at)enterprisedb(dot)com> wrote:

> Hi Jeevan,
>
> Thanks for the explanation and the pro() example, it is convincing.
> I hadn't considered this properly earlier. for SUM the overflow
> depends only on number of rows, but for PRODUCT it depends on the
> values itself, so it will overflow in very few steps whenever values
> are more than 1. So native fast path will help only for columns
> having mostly 0, 1 or -1, not for large tables in general. I also
> checked int128.h and you are right, there is no existing function
> for overflow-checked "int128 *= int64" type of multiply, so this
> needs new code, not reuse of the SUM(int8) pattern. So agree, fine to
> take this up later as a follow-up, no need to block on it.
>
> About your question on float8 vs numeric for float variants - I
> would prefer float8. sum(float4)/sum(float8) already return
> float4/float8, not numeric, so PRODUCT() staying same for float
> types will be more consistent. It also avoids the overflow-primitive
> problem for floats, since float just becomes Infinity instead of
> erroring out. For int2/int4/int8 numeric is fine as it is.
>
>
Thanks Vaibhav (and Dean, Jim, back in June) for pushing on this -- agreed,
we'll switch product(float4)/product(float8) to return float8 natively
rather
than numeric, consistent with sum(float4)/sum(float8).

Will post v3 with this change (float4/float8 -> float8) soon.

Thanks,

--
*Jeevan Chalke*
*Senior Principal Engineer, Engineering Manager*
*Product Development*

enterprisedb.com <https://www.enterprisedb.com>