On Tue, Sep 22, 2026 at 7:48 PM Jeevan Chalke < [email protected]> wrote:
> Hello, > > On Sun, Sep 13, 2026 at 12:23 PM Vaibhav Dalvi < > [email protected]> 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. > v3 attached. product(float4)/product(float8) now return double precision natively (no longer numeric), matching sum(float4)/sum(float8). Note: Like sum(), a finite product that would overflow double precision raises an error rather than silently becoming Infinity -- Infinity only results when it's already present in the input. Added a regression test covering this. Thanks, -- *Jeevan Chalke* *Senior Principal Engineer, Engineering Manager* *Product Development* enterprisedb.com <https://www.enterprisedb.com>
v3-0001-Add-PRODUCT-aggregate-function.patch
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