OTP 26.2.5 select performance with a map in the key

otp_26.2.4_output.txt

Operating System: macOS
CPU Information: Apple M3 Pro
Number of Available Cores: 12
Available memory: 36 GB
Elixir 1.16.1
Erlang 26.2.4
JIT enabled: true

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
reduction time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 21 s

Benchmarking lookup ...
Benchmarking select ...
Benchmarking select_reverse ...
Calculating statistics...
Formatting results...

Name                     ips        average  deviation         median         99th %
lookup             1587.69 K        0.63 μs  ±1754.84%        0.63 μs        0.79 μs
select              930.43 K        1.07 μs   ±366.70%        1.04 μs        1.25 μs
select_reverse      915.83 K        1.09 μs   ±349.99%        1.08 μs        1.29 μs

Comparison:
lookup             1587.69 K
select              930.43 K - 1.71x slower +0.44 μs
select_reverse      915.83 K - 1.73x slower +0.46 μs

otp_26.2.5_output.txt

Operating System: macOS
CPU Information: Apple M3 Pro
Number of Available Cores: 12
Available memory: 36 GB
Elixir 1.16.1
Erlang 26.2.5
JIT enabled: true

Benchmark suite executing with the following configuration:
warmup: 2 s
time: 5 s
memory time: 0 ns
reduction time: 0 ns
parallel: 1
inputs: none specified
Estimated total run time: 21 s

Benchmarking lookup ...
Benchmarking select ...
Benchmarking select_reverse ...
Calculating statistics...
Formatting results...

Name                     ips        average  deviation         median         99th %
lookup                1.62 M      616.07 ns  ±1798.74%         584 ns         791 ns
select_reverse        1.21 M      823.61 ns  ±1503.76%         667 ns         958 ns
select             0.00100 M   995660.57 ns     ±2.84%      982750 ns  1058731.74 ns

Comparison:
lookup                1.62 M
select_reverse        1.21 M - 1.34x slower +207.54 ns
select             0.00100 M - 1616.16x slower +995044.50 ns

select_bench.exs

tab = :ets.new(
  :metrics, [
  :compressed,
  :ordered_set,
  :protected,
  read_concurrency: true
])

sys_time = System.system_time(:second)
labels = %{"a" => 1, "b" => 2}

for offset <- 0..10_000 do
  time = sys_time - offset

  :ets.insert(tab, {{"exec_time", labels, time}, time, %{}})
end

key = {"exec_time", labels, sys_time - 1}
match = {key, sys_time - 1, :"$1"}

Benchee.run(%{
  "lookup" => fn ->
    :ets.lookup(tab, key)
  end,

  "select" => fn ->
    :ets.select(tab, [{match, [], [:"$1"]}], 1)
  end,

  "select_reverse" => fn ->
    :ets.select_reverse(tab, [{match, [], [:"$1"]}], 1)
  end
})