diff --git a/Gemfile.lock b/Gemfile.lock
index d88e9fe..4dc585e 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    parqueteur (1.3.2)
+    parqueteur (1.3.3)
       red-parquet (~> 6.0)
 
 GEM
diff --git a/examples/hello-world.rb b/examples/hello-world.rb
index a7456d8..18b9788 100644
--- a/examples/hello-world.rb
+++ b/examples/hello-world.rb
@@ -1,3 +1,4 @@
+require 'securerandom'
 require 'bundler/setup'
 require 'parqueteur'
 
@@ -17,14 +18,16 @@ class FooParquetConverter < Parqueteur::Converter
   column :my_timestamp, :timestamp
 end
 
-data = 100.times.collect do |i|
+data = 1000.times.collect do |i|
   {
     'id' => i,
     'my_string_array' => %w[a b c],
     'my_date' => Date.today,
     'my_decimal' => BigDecimal('0.03'),
     'my_int' => rand(1..10),
-    'my_map' => { 'a' => 'b' },
+    'my_map' => 20.times.each_with_object({}) do |idx, hash|
+      hash["k_#{idx}"] = SecureRandom.urlsafe_base64(64)
+    end,
     'my_string' => 'Hello World',
     'my_struct' => {
       'my_struct_str' => 'Hello World',
diff --git a/lib/parqueteur/converter.rb b/lib/parqueteur/converter.rb
index a5573fa..2476dc5 100644
--- a/lib/parqueteur/converter.rb
+++ b/lib/parqueteur/converter.rb
@@ -2,7 +2,7 @@
 
 module Parqueteur
   class Converter
-    DEFAULT_BATCH_SIZE = 10
+    DEFAULT_BATCH_SIZE = 100
 
     def self.inline(&block)
       Class.new(self, &block)
diff --git a/lib/parqueteur/types/map_type.rb b/lib/parqueteur/types/map_type.rb
index 86f896c..8ff7a0a 100644
--- a/lib/parqueteur/types/map_type.rb
+++ b/lib/parqueteur/types/map_type.rb
@@ -4,18 +4,7 @@ module Parqueteur
   module Types
     class MapType < Parqueteur::Type
       def build_value_array(values)
-        builder = Arrow::MapArrayBuilder.new(arrow_type)
-        values.each do |entry|
-          builder.append_value
-          next if entry.nil?
-
-          entry.each do |k, v|
-            builder.key_builder.append(k)
-            builder.item_builder.append(v)
-          end
-        end
-
-        builder.finish
+        Arrow::MapArrayBuilder.build(arrow_type, values)
       end
 
       def arrow_type_builder
diff --git a/lib/parqueteur/version.rb b/lib/parqueteur/version.rb
index e299397..f2faaac 100644
--- a/lib/parqueteur/version.rb
+++ b/lib/parqueteur/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Parqueteur
-  VERSION = '1.3.2'
+  VERSION = '1.3.3'
 end