RequestStore#fetch without &block

[chopraanmol1]

&block inside method definitions creates additional proc which consumes more time and memory.

One of the usecase of RequestStore is to memoize value on per request basis. Currently, in this scenario while using RequestStore#fetch unused proc will be created multiple times

Benchmark:

2.4.3 :001 > require 'memory_profiler'
 => true
2.4.3 :002 > require 'request_store'
 => true
2.4.3 :003 > require 'benchmark/ips'
 => true
2.4.3 :004 >
2.4.3 :005 >   module RequestStore
2.4.3 :006?>     def self.fetch_without_proc_creation(key)
2.4.3 :007?>         # Suggested
2.4.3 :008 >           store[key] = yield unless exist?(key)
2.4.3 :009?>         store[key]
2.4.3 :010?>       end
2.4.3 :011?>     def self.fetch_with_proc_creation(key, &block)
2.4.3 :012?>         # current
2.4.3 :013 >           store[key] = yield unless exist?(key)
2.4.3 :014?>         store[key]
2.4.3 :015?>       end
2.4.3 :016?>   end ; nil
 => nil
2.4.3 :017 >
2.4.3 :018 >   Benchmark.ips do |x|
2.4.3 :019 >       x.config(:time => 5, :warmup => 2)
2.4.3 :020?>     x.report("with &block") { RequestStore.fetch_with_proc_creation(:a){0} }
2.4.3 :021?>
2.4.3 :022 >       x.report("without &block") {RequestStore.fetch_without_proc_creation(:b){1}}
2.4.3 :023?>
2.4.3 :024 >       x.compare!
2.4.3 :025?>   end ; nil
Warming up --------------------------------------
         with &block   101.397k i/100ms
      without &block   157.885k i/100ms
Calculating -------------------------------------
         with &block      1.474M (± 2.6%) i/s -      7.402M in   5.024766s
      without &block      2.554M (± 1.9%) i/s -     12.789M in   5.009695s

Comparison:
      without &block:  2553852.9 i/s
         with &block:  1474212.3 i/s - 1.73x  slower

 => nil
2.4.3 :026 >
2.4.3 :027 >   MemoryProfiler.report{ 100.times{ RequestStore.fetch_with_proc_creation(:aa){0} } }.pretty_print(detailed_report: false, allocated_strings: false, retained_strings: 0)
Total allocated: 8000 bytes (100 objects)
Total retained:  0 bytes (0 objects)

Allocated String Report
-----------------------------------

 => nil
2.4.3 :028 >
2.4.3 :029 >   MemoryProfiler.report{ 100.times{ RequestStore.fetch_without_proc_creation(:bb){1} } }.pretty_print(detailed_report: false, allocated_strings: false, retained_strings: 0)
Total allocated: 0 bytes (0 objects)
Total retained:  0 bytes (0 objects)

Allocated String Report
-----------------------------------

 => nil
2.4.3 :030 >

[chopraanmol1]

Benchmarking Script

require 'memory_profiler'
require 'request_store'
require 'benchmark/ips'

module RequestStore
  def self.fetch_without_proc_creation(key)
    # Suggested
    store[key] = yield unless exist?(key)
    store[key]
  end
  def self.fetch_with_proc_creation(key, &block)
    # current
    store[key] = yield unless exist?(key)
    store[key]
  end
end ; nil

Benchmark.ips do |x|
  x.config(:time => 5, :warmup => 2)
  x.report("with &block") { RequestStore.fetch_with_proc_creation(:a){0} }

  x.report("without &block") {RequestStore.fetch_without_proc_creation(:b){1}}

  x.compare!
end ; nil

MemoryProfiler.report{ 100.times{ RequestStore.fetch_with_proc_creation(:aa){0} } }.pretty_print(detailed_report: false, allocated_strings: false, retained_strings: 0)

MemoryProfiler.report{ 100.times{ RequestStore.fetch_without_proc_creation(:bb){1} } }.pretty_print(detailed_report: false, allocated_strings: false, retained_strings: 0)

[steveklabnik]

Neat! I am happy to merge, but can't release a new version right this second; expect me to do so within a week. Thank you so much!

[chopraanmol1]

Ya sure no problem

[chopraanmol1]

Hey, @steveklabnik just wanted to remind you about merging this PR as it has already been 2 weeks.

[steveklabnik]

Yes, sorry. cutting a release. sorry for the delay.

[steveklabnik]

published as 1.4.1

[lvangool]

Nice work @chopraanmol1!