Add batching delay to commit options.

google/cloud/spanner/commit_options.cc

@@ -30,6 +30,9 @@ CommitOptions::CommitOptions(Options const& opts)
   if (opts.has<TransactionTagOption>()) {
     transaction_tag_ = opts.get<TransactionTagOption>();
   }
+  if (opts.has<MaxBatchingDelayMsOption>()) {
+    max_batching_delay_ms_ = opts.get<MaxBatchingDelayMsOption>();
+  }
 }
 
 CommitOptions::operator Options() const {

google/cloud/spanner/commit_options.h

@@ -70,6 +70,16 @@ class CommitOptions {
     return request_priority_;
   }
 
+  CommitOptions& set_max_batching_delay_ms(
+      int max_batching_delay_ms) {
+    max_batching_delay_ms_ = std::move(max_batching_delay_ms);
+    return *this;
+  }
+
+  absl::optional<int> max_batching_delay_ms() const {
+    return max_batching_delay_ms;
+  }
+
   /**
    * Set the transaction tag for the `spanner::Client::Commit()` call.
    * Ignored for the overload that already takes a `spanner::Transaction`.
@@ -90,6 +100,7 @@ class CommitOptions {
   // so we do not even provide a mechanism to specify one.
   bool return_stats_ = false;
   absl::optional<RequestPriority> request_priority_;
+  absl::optional<int> max_batching_delay_ms_;
   absl::optional<std::string> transaction_tag_;
 };
 

google/cloud/spanner/internal/connection_impl.cc

@@ -1025,6 +1025,12 @@ StatusOr<spanner::CommitResult> ConnectionImpl::CommitImpl(
   request.mutable_request_options()->set_priority(
       ProtoRequestPriority(params.options.request_priority()));
 
+  if (params.options.has<spanner::MaxBatchingDelayMsOption>()) {
+    *request.mutable_max_batching_delay() =
+      google::protobuf::util::TimeUtil::MillisecondsToDuration(
+       params.options.get<spanner::MaxBatchingDelayMsOption>());
+  }
+
   // params.options.transaction_tag() was either already used to set
   // ctx.tag (for a library-generated transaction), or it is ignored
   // (for a user-supplied transaction).

google/cloud/spanner/options.h

@@ -232,6 +232,15 @@ struct RequestPriorityOption {
   using Type = spanner::RequestPriority;
 };
 
+/**
+ * Option for `google::cloud::Options` to set a maximum batching delay.
+ *
+ * @ingroup spanner-options
+ */
+struct MaxBatchingDelayMsOption {
+  using Type = int;
+};
+
 /**
  * Option for `google::cloud::Options` to set a per-request tag.
  *

google/cloud/spanner/samples/samples.cc

@@ -3951,6 +3951,22 @@ void QueryInformationSchemaDatabaseOptions(
 }
 // [END spanner_query_information_schema_database_options]
 
+// [START spanner_commit_with_batching_delay]
+void UpdateDataWithBatchingDelay(google::cloud::spanner::Client client) {
+  namespace spanner = ::google::cloud::spanner;
+  Options ops;
+  ops.set<MaxBatchingDelayMsOption>(100);
+  auto commit_result = client.Commit(spanner::Mutations{
+      spanner::UpdateMutationBuilder("Albums",
+                                     {"SingerId", "AlbumId", "MarketingBudget"})
+          .EmplaceRow(1, 1, 100000)
+          .EmplaceRow(2, 2, 500000)
+          .Build()}, ops);
+  if (!commit_result) throw std::move(commit_result).status();
+  std::cout << "Update was successful [spanner_update_data]\n";
+}
+// [END spanner_set_batching_delay]
+
 std::string Basename(absl::string_view name) {
   auto last_sep = name.find_last_of("/\\");
   if (last_sep != absl::string_view::npos) name.remove_prefix(last_sep + 1);
@@ -4147,6 +4163,8 @@ int RunOneCommand(std::vector<std::string> argv) {
       make_command_entry("make-delete-mutation", MakeDeleteMutation),
       make_command_entry("query-information-schema-database-options",
                          QueryInformationSchemaDatabaseOptions),
+      make_command_entry("spanner-commit-with-batching-delay",
+			 UpdateDataWithBatchingDelay),
   };
 
   static std::string usage_msg = [&argv, &commands] {
@@ -4869,6 +4887,11 @@ void RunAll(bool emulator) {
     QueryInformationSchemaDatabaseOptions(client);
   }
 
+  if (!emulator) {
+    SampleBanner("spanner_commit_with_batching_delay");
+    UpdateDataWithBatchingDelay(client);
+  }
+
   if (!emulator) {
     SampleBanner("spanner_create_table_with_foreign_key_delete_cascade");
     CreateTableWithForeignKeyDeleteCascade(database_admin_client, project_id,