"Hitoshi Harada" <umi.tan...@gmail.com> writes: > 2009/1/8 Tom Lane <t...@sss.pgh.pa.us>: >> 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. In this particular case it's not hard, but in the general case where you are using any of the seekpos values it could require a significant amount of code. More to the point: the available examples suggest to me that truncating at the row you fetch is likely to be a pretty common behavior; in fact *every one* of the existing callers of WinGetFuncArgInPartition or WinGetFuncArgInFrame does that, at least conditionally. So I think it's reasonable to have an extra parameter instead of making a lot of callers reinvent the same wheel. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers