On Fri, 18 Aug 2017 at 4:48 PM, Amit Kapila <amit.kapil...@gmail.com> wrote:
> On Thu, Aug 17, 2017 at 2:45 PM, Dilip Kumar <dilipbal...@gmail.com> > wrote: > > On Thu, Aug 17, 2017 at 2:09 PM, Dilip Kumar <dilipbal...@gmail.com> > wrote: > >> > >> Either we can pass "num_gene" to merge_clump or we can store num_gene > >> in the root. And inside merge_clump we can check. Do you see some more > >> complexity? > >> > > I think something like that should work. Ok > > > > After putting some more thought I see one more problem but not sure > > whether we can solve it easily. Now, if we skip generating the gather > > path at top level node then our cost comparison while adding the > > element to pool will not be correct as we are skipping some of the > > paths (gather path). And, it's very much possible that the path1 is > > cheaper than path2 without adding gather on top of it but with gather, > > path2 can be cheaper. > > > > I think that should not matter because the costing of gather is mainly > based on a number of rows and that should be same for both path1 and > path2 in this case. Yeah, I think you are right. > > > > -- > With Regards, > Amit Kapila. > EnterpriseDB: http://www.enterprisedb.com > -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
