Re: +(pg_lsn, int8) and -(pg_lsn, int8) operators

On 2020/05/07 13:15, Fujii Masao wrote:
> 
> 
> On 2020/05/02 11:29, Michael Paquier wrote:
>> On Thu, Apr 30, 2020 at 11:40:59PM +0900, Fujii Masao wrote:
>>> Also the number of bytes can be added into and substracted from LSN using the
>>> <literal>+(pg_lsn,numeric)</literal> and <literal>-(pg_lsn,numeric)</literal>
>>> operators, respectively. Note that the calculated LSN should be in the range
>>> of <type>pg_lsn</type> type, i.e., between <literal>0/0</literal> and
>>> <literal>FFFFFFFF/FFFFFFFF</literal>.
>>> -----------------
>>
>> That reads fine.
> 
> Ok, I will update the docs in that way.

Done.

> 
>>
>>>> +   /* XXX would it be better to return NULL? */
>>>> +   if (NUMERIC_IS_NAN(num))
>>>> +       ereport(ERROR,
>>>> +               (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
>>>> +                errmsg("cannot convert NaN to pg_lsn")));
>>>> That would be good to test, and an error sounds fine to me.
>>>
>>> You mean that we should add the test that goes through this code block,
>>> into the regression test?
>>
>> Yes, that looks worth making sure to track, especially if the behavior
>> of this code changes in the future.
> 
> Ok, I will add that regression test.

Done. Attached is the updated version of the patch!

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION