diff --git a/google-cloud-spanner/.rubocop.yml b/google-cloud-spanner/.rubocop.yml
index 71b696e..36df750 100644
--- a/google-cloud-spanner/.rubocop.yml
+++ b/google-cloud-spanner/.rubocop.yml
@@ -16,6 +16,7 @@ Documentation:
 Metrics/BlockLength:
   Exclude:
     - "acceptance/**/*"
+    - ".toys.rb"
 Metrics/MethodLength:
   Exclude:
     - "acceptance/**/*"
diff --git a/google-cloud-spanner/.toys.rb b/google-cloud-spanner/.toys.rb
new file mode 100644
index 0000000..62d936b
--- /dev/null
+++ b/google-cloud-spanner/.toys.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+# Copyright 2024 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+toys_version! ">= 0.15.6"
+
+if ENV["RUBY_COMMON_TOOLS"]
+  common_tools_dir = File.expand_path ENV["RUBY_COMMON_TOOLS"]
+  load File.join(common_tools_dir, "toys", "gapic")
+else
+  load_git remote: "https://github.com/googleapis/ruby-common-tools.git",
+           path: "toys/gapic",
+           update: true
+end
+
+tool "benchmark" do
+  tool "gen-protos" do
+    include :exec, e: true
+    include :gems
+    include :git_cache
+
+    def run
+      setup
+      generate_spanner_bench
+    end
+
+    def setup
+      gem "grpc-tools", "~> 1.65"
+      @googleapis_dir = git_cache.get "https://github.com/googleapis/googleapis.git", update: true
+      Dir.chdir context_directory
+    end
+
+    def generate_spanner_bench
+      Dir.chdir "benchmark/benchwrapper" do
+        cmd = [
+          "grpc_tools_ruby_protoc",
+          "--ruby_out", ".",
+          "--grpc_out", ".",
+          "-I", ".",
+          "-I", @googleapis_dir,
+          "spanner_bench/spanner.proto"
+        ]
+        exec cmd
+      end
+    end
+  end
+end
diff --git a/google-cloud-spanner/benchmark/benchwrapper/benchwrapper.rb b/google-cloud-spanner/benchmark/benchwrapper/benchwrapper.rb
index b3c701e..9a627af 100755
--- a/google-cloud-spanner/benchmark/benchwrapper/benchwrapper.rb
+++ b/google-cloud-spanner/benchmark/benchwrapper/benchwrapper.rb
@@ -20,7 +20,7 @@
 
 require 'optparse'
 require 'grpc'
-require 'spanner_services_pb'
+require 'spanner_bench/spanner_services_pb'
 require "google/cloud/spanner"
 
 include SpannerBench
diff --git a/google-cloud-spanner/benchmark/benchwrapper/spanner.proto b/google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner.proto
similarity index 100%
rename from google-cloud-spanner/benchmark/benchwrapper/spanner.proto
rename to google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner.proto
diff --git a/google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner_pb.rb b/google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner_pb.rb
new file mode 100644
index 0000000..abb33ac
--- /dev/null
+++ b/google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner_pb.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: spanner_bench/spanner.proto
+
+require 'google/protobuf'
+
+
+descriptor_data = "\n\x1bspanner_bench/spanner.proto\x12\rspanner_bench\"P\n\x06Singer\x12\n\n\x02id\x18\x01 \x01(\x03\x12\x12\n\nfirst_name\x18\x02 \x01(\t\x12\x11\n\tlast_name\x18\x03 \x01(\t\x12\x13\n\x0bsinger_info\x18\x04 \x01(\t\";\n\x05\x41lbum\x12\n\n\x02id\x18\x01 \x01(\x03\x12\x11\n\tsinger_id\x18\x02 \x01(\x03\x12\x13\n\x0b\x61lbum_title\x18\x03 \x01(\t\"\x1a\n\tReadQuery\x12\r\n\x05query\x18\x01 \x01(\t\"[\n\x0bInsertQuery\x12&\n\x07singers\x18\x01 \x03(\x0b\x32\x15.spanner_bench.Singer\x12$\n\x06\x61lbums\x18\x02 \x03(\x0b\x32\x14.spanner_bench.Album\"\x1e\n\x0bUpdateQuery\x12\x0f\n\x07queries\x18\x01 \x03(\t\"\x0f\n\rEmptyResponse2\xe3\x01\n\x13SpannerBenchWrapper\x12@\n\x04Read\x12\x18.spanner_bench.ReadQuery\x1a\x1c.spanner_bench.EmptyResponse\"\x00\x12\x44\n\x06Insert\x12\x1a.spanner_bench.InsertQuery\x1a\x1c.spanner_bench.EmptyResponse\"\x00\x12\x44\n\x06Update\x12\x1a.spanner_bench.UpdateQuery\x1a\x1c.spanner_bench.EmptyResponse\"\x00\x62\x06proto3"
+
+pool = Google::Protobuf::DescriptorPool.generated_pool
+pool.add_serialized_file(descriptor_data)
+
+module SpannerBench
+  Singer = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.Singer").msgclass
+  Album = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.Album").msgclass
+  ReadQuery = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.ReadQuery").msgclass
+  InsertQuery = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.InsertQuery").msgclass
+  UpdateQuery = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.UpdateQuery").msgclass
+  EmptyResponse = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.EmptyResponse").msgclass
+end
diff --git a/google-cloud-spanner/benchmark/benchwrapper/spanner_services_pb.rb b/google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner_services_pb.rb
similarity index 95%
rename from google-cloud-spanner/benchmark/benchwrapper/spanner_services_pb.rb
rename to google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner_services_pb.rb
index 0ada3f0..c840d56 100644
--- a/google-cloud-spanner/benchmark/benchwrapper/spanner_services_pb.rb
+++ b/google-cloud-spanner/benchmark/benchwrapper/spanner_bench/spanner_services_pb.rb
@@ -1,5 +1,5 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
-# Source: spanner.proto for package 'spanner_bench'
+# Source: spanner_bench/spanner.proto for package 'spanner_bench'
 # Original file comments:
 # Copyright 2020 Google LLC
 #
@@ -17,7 +17,7 @@
 #
 
 require 'grpc'
-require 'spanner_pb'
+require 'spanner_bench/spanner_pb'
 
 module SpannerBench
   module SpannerBenchWrapper
diff --git a/google-cloud-spanner/benchmark/benchwrapper/spanner_pb.rb b/google-cloud-spanner/benchmark/benchwrapper/spanner_pb.rb
deleted file mode 100644
index c88f047..0000000
--- a/google-cloud-spanner/benchmark/benchwrapper/spanner_pb.rb
+++ /dev/null
@@ -1,55 +0,0 @@
-# Copyright 2020 Google LLC
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     https://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-# Generated by the protocol buffer compiler.  DO NOT EDIT!
-# source: spanner.proto
-
-require 'google/protobuf'
-
-Google::Protobuf::DescriptorPool.generated_pool.build do
-  add_file("spanner.proto", :syntax => :proto3) do
-    add_message "spanner_bench.Singer" do
-      optional :id, :int64, 1
-      optional :first_name, :string, 2
-      optional :last_name, :string, 3
-      optional :singer_info, :string, 4
-    end
-    add_message "spanner_bench.Album" do
-      optional :id, :int64, 1
-      optional :singer_id, :int64, 2
-      optional :album_title, :string, 3
-    end
-    add_message "spanner_bench.ReadQuery" do
-      optional :query, :string, 1
-    end
-    add_message "spanner_bench.InsertQuery" do
-      repeated :singers, :message, 1, "spanner_bench.Singer"
-      repeated :albums, :message, 2, "spanner_bench.Album"
-    end
-    add_message "spanner_bench.UpdateQuery" do
-      repeated :queries, :string, 1
-    end
-    add_message "spanner_bench.EmptyResponse" do
-    end
-  end
-end
-
-module SpannerBench
-  Singer = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.Singer").msgclass
-  Album = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.Album").msgclass
-  ReadQuery = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.ReadQuery").msgclass
-  InsertQuery = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.InsertQuery").msgclass
-  UpdateQuery = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.UpdateQuery").msgclass
-  EmptyResponse = ::Google::Protobuf::DescriptorPool.generated_pool.lookup("spanner_bench.EmptyResponse").msgclass
-end
diff --git a/google-cloud-spanner/lib/google/cloud/spanner/instance.rb b/google-cloud-spanner/lib/google/cloud/spanner/instance.rb
index 094a8b9..93d54fc 100644
--- a/google-cloud-spanner/lib/google/cloud/spanner/instance.rb
+++ b/google-cloud-spanner/lib/google/cloud/spanner/instance.rb
@@ -258,12 +258,13 @@ def save
           ensure_service!
 
           field_mask = []
-          @current_values.each do |field, value|
-            field_mask << field unless @grpc[field.to_s] == value
+          new_values = @grpc.to_h
+          (@current_values.keys + new_values.keys).uniq.each do |field|
+            field_mask << field unless new_values[field] == @current_values[field]
           end
 
           job_grpc = service.update_instance @grpc, field_mask: field_mask
-          @current_values = @grpc.to_h
+          @current_values = new_values
           Instance::Job.from_grpc job_grpc, service
         end
         alias update save