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

2009/1/8 Tom Lane <tgl@sss.pgh.pa.us>:
> "Hitoshi Harada" <umi.tanuki@gmail.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