perf: add index on created_at_unixtimestamp

app/models/daily_statistic.rb

@@ -61,3 +61,7 @@ def liquidity
 #  nodes_count                  :integer
 #  locked_capacity              :decimal(30, )
 #
+# Indexes
+#
+#  index_daily_statistics_on_created_at_unixtimestamp  (created_at_unixtimestamp)
+#

db/migrate/20201218065319_add_index_on_created_at_unixtimestamp_to_daily_statistics.rb

@@ -0,0 +1,5 @@
+class AddIndexOnCreatedAtUnixtimestampToDailyStatistics < ActiveRecord::Migration[6.0]
+  def change
+    add_index :daily_statistics, :created_at_unixtimestamp, order: { created_at_unixtimestamp: "DESC NULLS LAST" }
+  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: 2020_10_29_140549) do
+ActiveRecord::Schema.define(version: 2020_12_18_065319) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -237,6 +237,7 @@
     t.jsonb "nodes_distribution"
     t.integer "nodes_count"
     t.decimal "locked_capacity", precision: 30
+    t.index ["created_at_unixtimestamp"], name: "index_daily_statistics_on_created_at_unixtimestamp", order: "DESC NULLS LAST"
   end
 
   create_table "dao_contracts", force: :cascade do |t|