While profiling and optimizing some performance critical code, I noticed that Map.take was one of the biggest contributors to the overall runtime. So out of curiosity, I did a quick benchmark, to see whether there might be a better way to retrieve multiple values from a map at once (somewhere in the…

You should make sure to return the same values from all your benchmarks. I think Map.take will return a map, while in other benchmarks you get a list. for has an into option that you could use (It is a separate concern if you don’t need a map and you’re satisfied with a list, which would be a valid…

@michallepicki beat me by a few hours but – either return the same kind of value from each function or just discard them by explicitly returning nil. That should give you a bit more objective data to work with.

Here’s what I got comparing apples to apples: Operating System: macOS CPU Information: Intel(R) Core(TM) i9-9980HK CPU @ 2.40GHz Number of Available Cores: 16 Available memory: 64 GB Elixir 1.15.7 Erlang 26.0.2 Benchmark suite executing with the following configuration: warmup: 2 s time: 5 s memor…

Thank you! And of course, that makes sense! I knew I must be missing some detail :sweat_smile: However, within the code I was profiling the values of the map are what I need. So what I am actually doing is something like this: map |> Map.take(keys) |> Map.values() Thus I conclude, doing something…

I used your code with the exception of where it returned a list instead of a map. :slightly_smiling_face:

Not sure if I understand your question correctly. I do not know the keys explicitly, nor do I know how many keys I need to look up, so I think pattern matching will not be an option if that is what you are aiming at. Very much simplified, the code looks like this: def get_items_by_filters(%{} = i…

[image] Yegair: I think pattern matching will not be an option if that is what you are aiming at. Yep I was. :smiley: [image] Yegair: Thus I conclude, doing something like this will probably be faster in my case: for key <- keys, do: Map.get(map, key) Why though? It is visible from y…

Hm, maybe I’m still missing some important point, but my reasoning goes like this: Map.take is fastest, if what I need is a map. However, what I actually need are the values of the map, so I have to additionally call Map.values (or something similar) afterwards. No matter how fast that is, it will …

Quite interesting and yes, for 1000 values I’d think the same.

Elixir Programming Language Forum

Is Map.take slower than running Map.fetch repeatedly?

Questions & Help Questions

dimitarvp November 2, 2023, 12:07pm 6

Do you know which keys you will need beforehand?