Performance and memory usage fixes

[krzysiek1507]

Purpose

Performance and memory usage fixes.

Changes

1. {}.select {} is faster than {}.dup.reject because it doesn't duplicate nor create another hash.
2. {}.keys is always a new array so we can use sort! and save some memory.
3. 2x {}.select {} with different blocks are faster than one {}.partition { }.map { |h| Hash[h] }

require 'benchmark/ips'
require 'benchmark/memory'
require 'set'

hsh = { include: 1, fields: 2, meta: 3, links: 4, e: 5 }.freeze
ADAPTER_OPTION_KEYS = Set.new([:include, :fields, :adapter, :meta, :meta_key, :links, :serialization_context, :key_transform]).freeze

[:ips, :memory].each do |type|
  Benchmark.public_send(type) do |x|
    x.report('map') { adapter_options, serializer_options = hsh.partition { |k, _| ADAPTER_OPTION_KEYS.include? k }.map { |h| Hash[h] } }
    x.report('select') do
      adapter_options = hsh.select { |k, _| ADAPTER_OPTION_KEYS.include? k }
      serializer_options = hsh.reject { |k, _| ADAPTER_OPTION_KEYS.include? k }
    end

    x.compare!
  end

  [].sort
end


Warming up --------------------------------------
                 map    34.293k i/100ms
              select    47.284k i/100ms
Calculating -------------------------------------
                 map    415.582k (± 2.4%) i/s -      2.092M in   5.036739s
              select    529.549k (± 5.0%) i/s -      2.695M in   5.107481s

Comparison:
              select:   529548.5 i/s
                 map:   415581.6 i/s - 1.27x  slower

Calculating -------------------------------------
                 map   904.000  memsize (     0.000  retained)
                        11.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)
              select   384.000  memsize (     0.000  retained)
                         2.000  objects (     0.000  retained)
                         0.000  strings (     0.000  retained)

Comparison:
              select:        384 allocated
                 map:        904 allocated - 2.35x more

[bf4]

Looks like we need a pr to fix ci :(

[bf4]

rebase, add a note to the changelog, and we can merge

[krzysiek1507]

@bf4 all green!