Chao Li <li.evan.c...@gmail.com> 于2025年8月4日周一 11:11写道：
> I tested this patch locally and it works for me. > > However I doubt if it really improve performance. The original code > "contain_volatile_functions((Node *) rte->values_lists)" recursively work > through rte-values_list, and this patch move contain_volatile_functions() > into the for loop, and checks against every item of rte->values_list. As > entries of values_list could just be Const, contain_volatile_functions() > will then return immediately, so that this changes reduces total calls to > contain_volatile_functions(). From this perspective, this patch may improve > the performance. > > On the other side, let's say a case where a values_list contains 10 items, > and the last item is volatile. With the original code, it won't enter the > for loop, nothing will be built; with this patch, operations have been > performed on the first 9 items, but eventually it returns NULL when hit the > last item. So in this case, performance could be worse. > Yes, in this case, the original code scans the values_list, finds the volatile functions, and returns from convert_VALUES_to_ANY(). My patch will perform unnecessary convert_testexpr and eval_const_expressions work. Overall, I am afraid the burden could beat the gain. > It's not easy to evaluate performance gain. I'm not sure it's worth doing the change. If someone doesn't like the patch. I will withdraw it. > The new status of this patch is: Waiting on Author > Thanks for your review. Actually, the purpose of convert_VALUES_to_ANY() is only to convert the sublink that includes the Values expression to SAOP. I have a question: Can we move the convert_VALUES_to_ANY() to another place? For example:preprocess_qual_conditions(). In pull_up_sublinks_jointree_recurse(), what we want to do is to pull up the sublinks. -- Thanks, Tender Wang
