Reduce number of transactions for #mark_collection_as_read

lib/unread/readable.rb

@@ -27,17 +27,12 @@ def mark_collection_as_read(collection, reader)
             if global_timestamp && global_timestamp >= timestamp
               # The object is implicitly marked as read, so there is nothing to do
             else
-              # This transaction is needed, so that parent transaction won't rollback even there's an error.
-              ReadMark.transaction(requires_new: true) do
-                begin
-                  rm = obj.read_marks.where(reader_id: reader.id, reader_type: reader.class.base_class.name).first || obj.read_marks.build
-                  rm.reader_id   = reader.id
-                  rm.reader_type = reader.class.base_class.name
-                  rm.timestamp   = timestamp
-                  rm.save!
-                rescue ActiveRecord::RecordNotUnique
-                  raise ActiveRecord::Rollback
-                end
+              begin
+                rm = obj.read_marks.find_or_initialize_by(reader_id: reader.id, reader_type: reader.class.base_class.name)
+                rm.timestamp = timestamp
+                rm.save!
+              rescue ActiveRecord::RecordNotUnique
+                next
               end
             end
           end

spec/unread/readable_spec.rb

@@ -269,8 +269,7 @@
     it "should mark the rest as read when the first record is not unique" do
       Email.mark_as_read! [ @email1 ], for: @reader
 
-      allow(@email1).to receive_message_chain("read_marks.build").and_return(@email1.read_marks.build)
-      allow(@email1).to receive_message_chain("read_marks.where").and_return([])
+      allow(@email1).to receive("read_marks.find_or_initialize_by").and_return(@email1.read_marks.build)
 
       expect do
         Email.mark_as_read! [ @email1, @email2 ], for: @reader

unread.gemspec

@@ -26,7 +26,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'timecop'
   s.add_development_dependency 'sqlite3'
   s.add_development_dependency 'mysql2'
-  s.add_development_dependency 'pg'
+  s.add_development_dependency 'pg', '< 1'
   s.add_development_dependency 'rspec'
   s.add_development_dependency 'simplecov'
   s.add_development_dependency 'term-ansicolor'