> -----Original Message----- > From: Adriano dos Santos Fernandes [mailto:adrian...@gmail.com] > Sent: Martes, 27 de Octubre de 2015 6:40 > > The problem is that we can't go to evaluate blr_coalesce for a "null > stream".
Yes, I thought so but there are two cases with a null stream: - coalesce inside a view: if the view if the non-mandatory table in a left join, coalesce shouldn't run (the case in the tracker) - coalesce in a typical left join between two tables, obviously coalesce should run. :-) select lt.A, coalesce(rt.A, lt.A) from lt left join rt on <cond> I wasn't sure how to distinguish the two cases. I had two elements: indicator of end of stream and indicator that the relation was a view, but I need to make sure such view is the non-mandatory side of a left join. > Currently that can be done with blr_derived-expr but it's > very invasive > in the optimization process. I looked at it in the code but seemed like too much. ;-) > I've sent for Dmitry's analysis an idea to use a kind of > "runtime only" > blr_derived_expr. Nice to know. C. ------------------------------------------------------------------------------ Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
