diff --git a/Gemfile b/Gemfile
index 6db22ce..0291a3c 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,6 +4,8 @@ source 'https://rubygems.org'
 
 group :development, :test do
   gem 'combustion', github: 'pat/combustion', ref: '7d0d24c3f36ce0eb336177fc493be0721bc26665'
+  gem 'activerecord-postgres-hstore', require: false
+  gem 'simple_hstore_accessor', '~> 0.2', require: false
 end
 
 gem 'rack', '< 2' if RUBY_VERSION < '2.2.0'
diff --git a/lib/redis_counters/dumpers/engine.rb b/lib/redis_counters/dumpers/engine.rb
index ccc5024..67f79db 100644
--- a/lib/redis_counters/dumpers/engine.rb
+++ b/lib/redis_counters/dumpers/engine.rb
@@ -266,12 +266,8 @@ def columns_definition
                             'character varying(4000)'
                           when :integer, :serial, :number
                             'integer'
-                          when :date
-                            'date'
-                          when :timestamp
-                            'timestamp'
-                          when :boolean
-                            'boolean'
+                          when :date, :timestamp, :boolean, :hstore
+                            type.to_s
                           else
                             if type.is_a?(Array) && type.first == :enum
                               type.last.fetch(:name)
diff --git a/spec/internal/app/models/stats_by_day.rb b/spec/internal/app/models/stats_by_day.rb
index f0a71c1..6d8659a 100644
--- a/spec/internal/app/models/stats_by_day.rb
+++ b/spec/internal/app/models/stats_by_day.rb
@@ -1,2 +1,3 @@
 class StatsByDay < ActiveRecord::Base
+  store_accessor :params
 end
diff --git a/spec/internal/app/models/stats_total.rb b/spec/internal/app/models/stats_total.rb
index 2ada32c..13ed31c 100644
--- a/spec/internal/app/models/stats_total.rb
+++ b/spec/internal/app/models/stats_total.rb
@@ -1,2 +1,3 @@
 class StatsTotal < ActiveRecord::Base
+  store_accessor :params
 end
diff --git a/spec/internal/db/schema.rb b/spec/internal/db/schema.rb
index 47a7b55..6549291 100644
--- a/spec/internal/db/schema.rb
+++ b/spec/internal/db/schema.rb
@@ -3,12 +3,21 @@
     CREATE TYPE subject_types AS ENUM ('');
   SQL
 
+  if ::ActiveRecord::VERSION::MAJOR < 4
+    execute <<-SQL
+      CREATE EXTENSION IF NOT EXISTS hstore;
+    SQL
+  else
+    enable_extension :hstore
+  end
+
   create_table :stats_by_days do |t|
     t.integer :record_id, null: false
     t.integer :column_id, null: false
     t.date :date, null: false
     t.integer :hits, null: false, default: 0
     t.column :subject, :subject_types
+    t.hstore :params
   end
 
   add_index :stats_by_days, [:record_id, :column_id, :date], unique: true
@@ -18,6 +27,7 @@
     t.integer :column_id, null: false
     t.integer :hits, null: false, default: 0
     t.column :subject, :subject_types
+    t.hstore :params
   end
 
   add_index :stats_totals, [:record_id, :column_id], unique: true
diff --git a/spec/lib/redis_counters/dumpers/engine_spec.rb b/spec/lib/redis_counters/dumpers/engine_spec.rb
index 044a93d..d3c791d 100644
--- a/spec/lib/redis_counters/dumpers/engine_spec.rb
+++ b/spec/lib/redis_counters/dumpers/engine_spec.rb
@@ -8,12 +8,13 @@
              column_id: :integer,
              value: :integer,
              date: :date,
-             subject: [:enum, {name: :subject_types}]
+             subject: [:enum, {name: :subject_types}],
+             params: :hstore
 
       destination do
         model StatsByDay
-        take :record_id, :column_id, :hits, :date
-        key_fields :record_id, :column_id, :date
+        take :record_id, :column_id, :hits, :date, :params
+        key_fields :record_id, :column_id, :date, :params
         increment_fields :hits
         map :hits, to: :value
         condition 'target.date = :date'
@@ -21,8 +22,8 @@
 
       destination do
         model StatsTotal
-        take :record_id, :column_id, :hits
-        key_fields :record_id, :column_id
+        take :record_id, :column_id, :hits, :params
+        key_fields :record_id, :column_id, :params
         increment_fields :hits
         map :hits, to: :value
       end
@@ -52,7 +53,7 @@
     RedisCounters.create_counter(Redis.current,
       counter_class: RedisCounters::HashCounter,
       counter_name: :record_hits_by_day,
-      group_keys: [:record_id, :column_id, :subject],
+      group_keys: [:record_id, :column_id, :subject, :params],
       partition_keys: [:date]
     )
   end
@@ -63,35 +64,39 @@
 
   describe '#process!' do
     before do
-      counter.increment(date: prev_date_s, record_id: 1, column_id: 100, subject: '')
-      counter.increment(date: prev_date_s, record_id: 1, column_id: 200, subject: '')
-      counter.increment(date: prev_date_s, record_id: 1, column_id: 200, subject: '')
-      counter.increment(date: prev_date_s, record_id: 2, column_id: 100, subject: nil)
+      counter.increment(date: prev_date_s, record_id: 1, column_id: 100, subject: '', params: '')
+      counter.increment(date: prev_date_s, record_id: 1, column_id: 200, subject: '', params: '')
+      counter.increment(date: prev_date_s, record_id: 1, column_id: 200, subject: '', params: '')
+      counter.increment(date: prev_date_s, record_id: 2, column_id: 100, subject: nil, params: '')
+
+      params = {a: 1}.stringify_keys.to_s[1..-2]
+      counter.increment(date: prev_date_s, record_id: 3, column_id: 300, subject: nil, params: params)
 
       dumper.process!(counter, date: prev_date)
 
-      counter.increment(date: date_s, record_id: 1, column_id: 100, subject: '')
-      counter.increment(date: date_s, record_id: 1, column_id: 200, subject: '')
-      counter.increment(date: date_s, record_id: 1, column_id: 200, subject: '')
-      counter.increment(date: date_s, record_id: 2, column_id: 100, subject: nil)
+      counter.increment(date: date_s, record_id: 1, column_id: 100, subject: '', params: '')
+      counter.increment(date: date_s, record_id: 1, column_id: 200, subject: '', params: '')
+      counter.increment(date: date_s, record_id: 1, column_id: 200, subject: '', params: '')
+      counter.increment(date: date_s, record_id: 2, column_id: 100, subject: nil, params: '')
 
       dumper.process!(counter, date: date)
     end
 
-    Then { expect(StatsByDay.count).to eq 6 }
+    Then { expect(StatsByDay.count).to eq 7 }
     And { expect(StatsByDay.where(record_id: 1, column_id: 100, date: prev_date).first.hits).to eq 1 }
     And { expect(StatsByDay.where(record_id: 1, column_id: 200, date: prev_date).first.hits).to eq 2 }
     And { expect(StatsByDay.where(record_id: 2, column_id: 100, date: prev_date).first.hits).to eq 1 }
+    And { expect(StatsByDay.where(record_id: 3, column_id: 300, date: prev_date).first.params).to eq("a" => "1") }
     And { expect(StatsByDay.where(record_id: 1, column_id: 100, date: date).first.hits).to eq 1 }
     And { expect(StatsByDay.where(record_id: 1, column_id: 200, date: date).first.hits).to eq 2 }
     And { expect(StatsByDay.where(record_id: 2, column_id: 100, date: date).first.hits).to eq 1 }
 
-    And { expect(StatsTotal.count).to eq 3 }
+    And { expect(StatsTotal.count).to eq 4 }
     And { expect(StatsTotal.where(record_id: 1, column_id: 100).first.hits).to eq 2 }
     And { expect(StatsTotal.where(record_id: 1, column_id: 200).first.hits).to eq 4 }
     And { expect(StatsTotal.where(record_id: 2, column_id: 100).first.hits).to eq 2 }
 
-    And { expect(StatsAggTotal.count).to eq 2 }
+    And { expect(StatsAggTotal.count).to eq 3 }
     And { expect(StatsAggTotal.where(record_id: 1).first.hits).to eq 6 }
     And { expect(StatsAggTotal.where(record_id: 2).first.hits).to eq 2 }
 
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 9ab4c25..984d32c 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -2,6 +2,11 @@
 require 'bundler/setup'
 require 'redis_counters/dumpers'
 
+if ::ActiveRecord::VERSION::MAJOR < 4
+  require 'activerecord-postgres-hstore'
+  require 'simple_hstore_accessor'
+end
+
 require 'combustion'
 Combustion.initialize! :active_record