alekseyl

def compare_cpu_general( scope, base_collection_size, nesting)
  ids = scope.ids
  ActiveRecord::Base.logger.silence do
    Benchmark.bmbm do |benchmark|
       benchmark.report("eager_load") do
        50.times do
          # sample(base_collection_size + 1) and limit(base_collection_size) 
          # added to imitate real limit for eager_load, so it would be obligated to use 2 queries instead of one
          # for more read here: https://medium.com/p/5ce11870de62
          scope.where(id: ids.sample(base_collection_size + 1)).limit(base_collection_size).eager_load(nesting).load

alekseyl

require 'memory_profiler'
require 'terminal-table'

def compare_ram(scope, base_collection_size, nesting)
  ids = scope.ids
  ids_sample = ids.sample(base_collection_size) # it should be the same id for both tests, since we comparing memory consumption

  # just to keep from memory profiler objects oblivion, and get retain numbers correctly
  el, pr = []
  preload = MemoryProfiler.report do

alekseyl

# This is a simple gist for performance and RAM usage testing for a nested_select gem
# 
# Objects relations: course -> topics -> lessons ( all relations are has_many )
# 
# ------------------------------------------------------------------------- 
# Schemas: 
# 
#   create_table "lessons", force: :cascade do |t|
#     t.string "title", null: false, comment: "Тема урока"
#     t.string "description", null: false, comment: "Описание урока"

alekseyl

alekseyl

alekseyl

class CommentsController < ApplicationController
  # I assumed the usual naming for models and foreign columns 
  def users_comments
    # I don't like where( post_id: Post.all ) but if table comments 
    # contains deleted posts comments or even NULLs than we need to keep it this way 
    @user_comments = Comment.where( post_id: Post.all )
                            .where(author_id: Author.where( username: params[:username]) )

  end
end

alekseyl

Redis.include( MeRedis )
# zip key crumbs user, card, card_preview, zips integer crumbs to base62, 
# for keys starting with card_preview prefix compress values with Zlib 
# for keys starting with user or card compress values with ActiveRecordJSONCompressor
Redis.configure( 
  hash_max_ziplist_entries: 256,
  zip_crumbs: %i[user card card_preview], # -> { user: :u, card: :c, card_preview: :c0 }
  integers_to_base62: true,
  compress_namespaces: {
      :card_preview => MeRedis::ZipValues::ZlibCompressor,

alekseyl

module RSmazCompressor
  def self.compress(value); RSmaz.compress(value) end
  def self.decompress(value); RSmaz.decompress(value) end
end

module ZLibJSONCompressor
  def self.compress(value); Zlib.deflate(value.to_json) end
  def self.decompress(value); JSON.load( Zlib.inflate( value ) )end
end

alekseyl

 def calc_me_redis_perfomance_hash_zipping( zip_max = 128, sample_size = 10000 )
    Redis.include(MeRedis)
    redis = Redis.new

    Redis.configure do |c|
      c.zip_crumbs = :user
      c.integers_to_base62 = true
      c.hash_max_ziplist_entries = zip_max
    end
    

alekseyl

# Columns: 
# redis - clear memory usage of 100K values in Mb, 
# gz - gz compressed value, smaz = smaz compressed value, 
# key zip = zipping key crumbs to cingle char, 
# me_ - memory_efficient_ hash optimization

#integers, html pieces, plain english text pieces 
+----------+--------+--------+--------+---------+--------+----------+------------+
| type     | redis  | gz     | smaz   | key zip | me_*   | kz+me+gz | kz+me+smaz |
+----------+--------+--------+--------+---------+--------+----------+------------+