Re: Sample of user-define window function and other things

2009/1/8 Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>:
> "Hitoshi Harada" <umi(dot)tanuki(at)gmail(dot)com> writes:
>> - Is WinGetFuncArgInPartition()'s argument mark_pos required? For the
>> newbies to window functions, it seems a bit confusing, but
>> WinSetMarkPos() looks enough for the purpose AFAIK.
>
> You mean set_mark? It's just to save an extra calculation of the
> absolute location of the fetched row. See leadlag_common for an
> example use: we can truncate the tuplestore if the offset is constant.

Yeah, I mean set_mark :P) I already checked leadlag_common example but
abs_pos can be very simply calculated by WinGetCurrentPosition() -
offset. So the simpler API is winner to me rather than saving few
cycle cpu cost.

Regards,

--
Hitoshi Harada