Feature Requests item #1120789, was opened at 2005-02-11 15:11 Message generated for change (Comment added) made by mlkersten You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=482471&aid=1120789&group_id=56967
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: MonetDB - modules Group: None >Status: Closed Priority: 5 Private: No Submitted By: Roberto Cornacchia (cornuz) Assigned to: Nobody/Anonymous (nobody) Summary: M4: non-equality select Initial Comment: As far as I know, only equality and range selects are efficiently implemented. A non-equality select (that I find a very common operation) can be performed as: [ifelse]([=](b,value),b); This is very inefficient though. the result of [=](b,value) is materialized before the actual selection, which can be very costly if b is a large bat. I'd find very useful a native implementation of non-equality selections. ---------------------------------------------------------------------- >Comment By: Martin Kersten (mlkersten) Date: 2009-12-04 14:31 Message: Correct. this will not be implemented anymore ---------------------------------------------------------------------- Comment By: Fabian (mr-meltdown) Date: 2009-12-01 11:57 Message: M4 is pretty deprecated, so this request may as well be closed, perhaps ---------------------------------------------------------------------- Comment By: Roberto Cornacchia (cornuz) Date: 2005-02-11 15:33 Message: Logged In: YES user_id=883451 No problem for the delay. Unfortunately these two alternatives might be even more expensive, if the original bat was ordered on the head and you want to preserve this property (which is often the case): in that case a sort() would be necessary afterwards.... :( ---------------------------------------------------------------------- Comment By: Stefan Manegold (stmane) Date: 2005-02-11 15:26 Message: Logged In: YES user_id=572415 good point, though I don't know when this feature will be added... for now, union( select(b,nil,value,FALSE.FALSE), select(b,value,nil,FALSE.FALSE) ); or select(b,nil,value,FALSE.FALSE).access(BAT_APPEND).insert(select(b,value,nil,FALSE.FALSE).access(BAT_READ); might be some (more efficient?) alternatives... ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=482471&aid=1120789&group_id=56967 ------------------------------------------------------------------------------ Join us December 9, 2009 for the Red Hat Virtual Experience, a free event focused on virtualization and cloud computing. Attend in-depth sessions from your desk. Your couch. Anywhere. http://p.sf.net/sfu/redhat-sfdev2dev _______________________________________________ Monetdb-bugs mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/monetdb-bugs
