Re: A little cosmetic to convert_VALUES_to_ANY()
От | Chao Li |
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Тема | Re: A little cosmetic to convert_VALUES_to_ANY() |
Дата | |
Msg-id | 175427705343.1031.14841847789593715999.pgcf@coridan.postgresql.org обсуждение исходный текст |
Ответ на | Re: A little cosmetic to convert_VALUES_to_ANY() (Tender Wang <tndrwang@gmail.com>) |
Ответы |
Re: A little cosmetic to convert_VALUES_to_ANY()
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Список | pgsql-hackers |
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 forloop, 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 originalcode, it won't enter the for loop, nothing will be built; with this patch, operations have been performed on thefirst 9 items, but eventually it returns NULL when hit the last item. So in this case, performance could be worse. Overall, I am afraid the burden could beat the gain. The new status of this patch is: Waiting on Author
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