Re: [HACKERS] pow support for pgbench

On Mon, Dec 4, 2017 at 10:47 AM, Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr> wrote:
>> What's the name of the backend function whose behavior this matches?
>>
>> As Fabien has mentioned, it tries to behave as "numeric_power". Maybe we
>> it'd better if we switch to "dpow" (which is pow with some error handling)
>> and always return a double. What do you think?
>
> My 0.02€: I think that having a integer pow implementation when possible is
> a good think for pgbench, because the main use case is to deal with table
> keys in a benchmarking scripts, which are expected to be integers.

I'm willing to commit any of the following things:

1. A patch that adds an integer version of pow() but not a double version
2. A patch that adds a double version of pow() but not an integer version
3. A patch that adds both an integer version of pow() and a double
version of pow(), with the two versions having different names

If Raúl is happy with only having an integer version, then I suggest
that he adopt #1 and call it good. Otherwise, given that Fabien wants
the double version, I suggest we call the integer version pow() and
the double version dpow() and go with #3.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company