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? > 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. But, there is not an easy way to handle it because without targetlist we can not calculate the cost of the gather(which is the actual problem).
-- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
