On Sun, 1 Oct 2023 at 21:26, Andy Fan <zhihui.fan1...@gmail.com> wrote: >> But overall, I'm more inclined to just go with the more simple "add a >> cheap unordered startup append path if considering cheap startup >> plans" version. I see your latest patch does both. So, I'd suggest two >> patches as I do see the merit in keeping this simple and cheap. If we >> can get the first part in and you still find cases where you're not >> getting the most appropriate startup plan based on the tuple fraction, >> then we can reconsider what extra complexity we should endure in the >> code based on the example query where we've demonstrated the planner >> is not choosing the best startup path appropriate to the given tuple >> fraction. > > I think this is a fair point, I agree that your first part is good enough to > be > committed first. Actually I tried a lot to make a test case which can prove > the value of cheapest fractional cost but no gain so far:(
I've attached a patch with the same code as the previous patch but this time including a regression test. I see no reason to not commit this so if anyone feels differently please let me know. David
consider_cheapest_startup_appendpath_v2.patch
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