Fix missing data bug

README.md

@@ -50,7 +50,7 @@ ActiveRecord 3.2.x and 4.x (mysql and mysql2 adapters).
 
 ## Limitations
 
-Due to the Chunker implementation, Lhm requires that the table to migrate has a
+Due to the Chunker implementation, Lhm requires that the table to migrate has
 a single integer numeric key column called `id`.
 
 Another note about the Chunker, it performs static sized row copies against the `id`
@@ -78,6 +78,7 @@ ActiveRecord::Base.establish_connection(
 # and migrate
 Lhm.change_table :users do |m|
   m.add_column :arbitrary, "INT(12)"
+  m.add_column :locale, "VARCHAR(2) NOT NULL DEFAULT 'en'"
   m.add_index  [:arbitrary_id, :created_at]
   m.ddl("alter table %s add column flag tinyint(1)" % m.name)
 end

lib/lhm/chunker.rb

@@ -27,7 +27,7 @@ def initialize(migration, connection = nil, options = {})
     def execute
       return unless @start && @limit
       @next_to_insert = @start
-      while @next_to_insert < @limit || (@start == @limit)
+      while @next_to_insert <= @limit
         stride = @throttler.stride
         affected_rows = @connection.update(copy(bottom, top(stride)))
 

spec/unit/chunker_spec.rb

@@ -107,13 +107,56 @@ def @throttler.stride
       @connection.verify
     end
 
+    it 'correctly copies single record tables when start is not 1' do
+      @chunker = Lhm::Chunker.new(@migration, @connection, :throttler => @throttler,
+                                                           :start     => 2,
+                                                           :limit     => 2)
+
+      @connection.expect(:update, 1) do |stmt|
+        stmt = stmt.first if stmt.is_a?(Array)
+        stmt =~ /between 2 and 2/
+      end
+
+      @chunker.run
+      @connection.verify
+    end
+
+    it 'correctly copies every record tables when difference is a multiple of stride plus one' do
+      def @throttler.stride
+        2
+      end
+      @chunker = Lhm::Chunker.new(@migration, @connection, :throttler => @throttler,
+                                                           :start     => 1,
+                                                           :limit     => 5)
+
+      @connection.expect(:update, 2) do |stmt|
+        stmt = stmt.first if stmt.is_a?(Array)
+        stmt =~ /between 1 and 2/
+      end
+      @connection.expect(:update, 2) do |stmt|
+        stmt = stmt.first if stmt.is_a?(Array)
+        stmt =~ /between 3 and 4/
+      end
+      @connection.expect(:update, 1) do |stmt|
+        stmt = stmt.first if stmt.is_a?(Array)
+        stmt =~ /between 5 and 5/
+      end
+
+      @chunker.run
+      @connection.verify
+    end
+
     it 'separates filter conditions from chunking conditions' do
+      def @throttler.stride
+        2
+      end
       @chunker = Lhm::Chunker.new(@migration, @connection, :throttler => @throttler,
                                                            :start     => 1,
                                                            :limit     => 2)
       @connection.expect(:update, 1) do |stmt|
         stmt = stmt.first if stmt.is_a?(Array)
         stmt =~ /where \(foo.created_at > '2013-07-10' or foo.baz = 'quux'\) and `foo`/
+        stmt =~ /between 1 and 2/
       end
 
       def @migration.conditions
@@ -125,12 +168,16 @@ def @migration.conditions
     end
 
     it "doesn't mess with inner join filters" do
+      def @throttler.stride
+        2
+      end
       @chunker = Lhm::Chunker.new(@migration, @connection, :throttler => @throttler,
                                                            :start     => 1,
                                                            :limit     => 2)
       @connection.expect(:update, 1) do |stmt|
         stmt = stmt.first if stmt.is_a?(Array)
         stmt =~ /inner join bar on foo.id = bar.foo_id and/
+        stmt =~ /between 1 and 2/
       end
 
       def @migration.conditions