cache validator counter

app/controllers/api/statistics_controller.rb

@@ -30,8 +30,9 @@ def index
   #   }
   # ]
   def proposals
-    result = Block.where.not(block_number: 0).group("header ->> 'proposer'").count
-               .map { |k, v| { validator: k, count: v } }
+    # result = Block.where.not(block_number: 0).group("header ->> 'proposer'").count
+    #            .map { |k, v| { validator: k, count: v } }
+    result = ValidatorCache.all.map { |c| { validator: c.name, count: c.counter } }
 
     render json: {
       result: result

app/models/block.rb

@@ -9,10 +9,20 @@ class Block < ApplicationRecord
 
   store_accessor :header, :timestamp
 
+  after_create :increase_validator_count
+
   # get current last block number in database
   #
   # @return [Integer, nil] the current last block number or nil if no block found in db.
   def self.current_block_number
     Block.order(block_number: :desc).first&.block_number
   end
+
+  private
+
+  # increase validator count after block create
+  def increase_validator_count
+    return if self.block_number.zero?
+    ValidatorCache.increase(self.header["proposer"])
+  end
 end

app/models/validator_cache.rb

@@ -0,0 +1,22 @@
+class ValidatorCache < ApplicationRecord
+  validates :name, presence: true, uniqueness: true
+
+  # increase a validator's count
+  #
+  # @param name [String] Block header proposer
+  # @return [void]
+  def self.increase(name)
+    # add transaction for lock cache
+    ApplicationRecord.transaction do
+      return if name.blank?
+      cache = ValidatorCache.find_by(name: name)
+      if cache.nil?
+        ValidatorCache.create(name: name, counter: 1)
+      else
+        # lock it
+        cache.lock!
+        cache.update!(counter: cache.counter + 1)
+      end
+    end
+  end
+end

db/migrate/20180903024536_create_validator_caches.rb

@@ -0,0 +1,23 @@
+class CreateValidatorCaches < ActiveRecord::Migration[5.2]
+  def change
+    create_table :validator_caches do |t|
+      t.string :name, null: false, index: { unique: true }
+      t.integer :counter
+
+      t.timestamps
+    end
+
+    reversible do |dir|
+      dir.up do
+        # create validator cache for present blocks
+        ApplicationRecord.transaction do
+          Block.where.not(block_number: 0).group("header ->> 'proposer'").count.each do |k, v|
+            cache = ValidatorCache.find_or_create_by(name: k)
+            cache.lock!
+            cache.update(counter: v)
+          end
+        end
+      end
+    end
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2018_08_30_054052) do
+ActiveRecord::Schema.define(version: 2018_09_03_024536) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -83,4 +83,12 @@
     t.index ["cita_hash"], name: "index_transactions_on_cita_hash", unique: true
   end
 
+  create_table "validator_caches", force: :cascade do |t|
+    t.string "name", null: false
+    t.integer "counter"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["name"], name: "index_validator_caches_on_name", unique: true
+  end
+
 end

spec/factories/validator_caches.rb

@@ -0,0 +1,5 @@
+FactoryBot.define do
+  factory :validator_cache, class: 'ValidatorCache' do
+    name "0x91827976af27e1fd405469b00dc8d3b0ea2203f6"
+  end
+end

spec/models/block_spec.rb

@@ -52,4 +52,22 @@
       expect(Block.current_block_number).to eq block.block_number
     end
   end
+
+  context "after create" do
+    context "increase_validator_count" do
+      it "not cache if block_number.zero?" do
+        block = create :block_zero, block_number: 0
+        proposer = block.header['proposer']
+        expect(proposer.blank?).not_to be true
+        expect(ValidatorCache.exists?(name: proposer)).to be false
+      end
+
+      it "cache if block_number not eq zero" do
+        block = create :block_one, block_number: 1
+        proposer = block.header["proposer"]
+        expect(proposer.blank?).not_to be true
+        expect(ValidatorCache.find_by(name: proposer).counter).to eq 1
+      end
+    end
+  end
 end

spec/models/validator_cache_spec.rb

@@ -0,0 +1,26 @@
+require 'rails_helper'
+
+RSpec.describe ValidatorCache, type: :model do
+  let(:proposer) { attributes_for(:validator_cache)[:name] }
+
+  context "increase" do
+    it "counter be 1 if not exist" do
+      expect(ValidatorCache.exists?(name: proposer)).to be false
+      expect {
+        ValidatorCache.increase(proposer)
+      }.to change { ValidatorCache.count }.by(1)
+      cache = ValidatorCache.find_by(name: proposer)
+      expect(cache.counter).to eq 1
+    end
+
+    it "counter add 1 if exist" do
+      counter = 5
+      create :validator_cache, counter: counter
+      expect {
+        ValidatorCache.increase(proposer)
+      }.to change { ValidatorCache.count }.by(0)
+      cache = ValidatorCache.find_by(name: proposer)
+      expect(cache.counter).to eq (counter + 1)
+    end
+  end
+end