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

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.

>
>>> + /* 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.

Regards,

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