feat(spanner): Enable multiplex sessions by default for all operations (#12734)

* feat(spanner): Enable multiplex sessions by default for all operations

* Fix regular and multiplex session tests

* update emulator version

Author: sakthivelmanii

spanner/batch_test.go

@@ -245,6 +245,9 @@ func TestPartitionQuery_Parallel(t *testing.T) {
 }
 
 func TestPartitionQuery_Multiplexed(t *testing.T) {
+	if !isMultiplexEnabled {
+		t.Skip("Skipping multiplex session tests when regular sessions enabled")
+	}
 	t.Parallel()
 	ctx := context.Background()
 	server, client, teardown := setupMockedTestServerWithConfig(t, ClientConfig{
@@ -309,6 +312,9 @@ func TestPartitionQuery_Multiplexed(t *testing.T) {
 }
 
 func TestPartitionRead_Multiplexed(t *testing.T) {
+	if !isMultiplexEnabled {
+		t.Skip("Skipping multiplex session tests when regular sessions enabled")
+	}
 	t.Parallel()
 	ctx := context.Background()
 	server, client, teardown := setupMockedTestServerWithConfig(t, ClientConfig{

spanner/benchmarks/README.md

@@ -36,8 +36,8 @@ Please look at the [Configurations](#configurations) section for allowed options
 
 To enable some application specific configurations, you can reference the following table.
 
-| Description                | Environment variable                           |
-|----------------------------|------------------------------------------------|
-| Enabling multiplex session | GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS=true |
-| Enabling directpath        | GOOGLE_SPANNER_ENABLE_DIRECT_ACCESS=true       |
+| Description                 | Environment variable                            |
+|-----------------------------|-------------------------------------------------|
+| Disabling multiplex session | GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS=false |
+| Enabling directpath         | GOOGLE_SPANNER_ENABLE_DIRECT_ACCESS=true        |
 

spanner/client.go

@@ -553,27 +553,36 @@ func newClientWithConfig(ctx context.Context, database string, config ClientConf
 		md.Append(afeMetricHeader, "true")
 	}
 
-	if isMultiplexed := strings.ToLower(os.Getenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS")); isMultiplexed != "" && !config.enableMultiplexSession {
-		config.enableMultiplexSession, err = strconv.ParseBool(isMultiplexed)
+	if isMultiplexed, found := os.LookupEnv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS"); found {
+		config.enableMultiplexSession, err = strconv.ParseBool(strings.ToLower(isMultiplexed))
 		if err != nil {
 			return nil, spannerErrorf(codes.InvalidArgument, "GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS must be either true or false")
 		}
+	} else {
+		config.enableMultiplexSession = true
 	}
-	if isMultiplexForRW := os.Getenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS_FOR_RW"); isMultiplexForRW != "" && !config.enableMultiplexedSessionForRW {
-		config.enableMultiplexedSessionForRW, err = strconv.ParseBool(isMultiplexForRW)
+
+	if isMultiplexForRW, found := os.LookupEnv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS_FOR_RW"); found {
+		config.enableMultiplexedSessionForRW, err = strconv.ParseBool(strings.ToLower(isMultiplexForRW))
 		if err != nil {
 			return nil, spannerErrorf(codes.InvalidArgument, "GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS_FOR_RW must be either true or false")
 		}
-		config.enableMultiplexedSessionForRW = config.enableMultiplexedSessionForRW && config.SessionPoolConfig.enableMultiplexSession
+	} else {
+		config.enableMultiplexedSessionForRW = true
 	}
-	if isMultiplexForPartitionOps := os.Getenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS_PARTITIONED_OPS"); isMultiplexForPartitionOps != "" && !config.enableMultiplexedSessionForPartitionedOps {
-		config.enableMultiplexedSessionForPartitionedOps, err = strconv.ParseBool(isMultiplexForPartitionOps)
+
+	if isMultiplexForPartitionOps, found := os.LookupEnv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS_PARTITIONED_OPS"); found {
+		config.enableMultiplexedSessionForPartitionedOps, err = strconv.ParseBool(strings.ToLower(isMultiplexForPartitionOps))
 		if err != nil {
 			return nil, spannerErrorf(codes.InvalidArgument, "GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS_PARTITIONED_OPS must be either true or false")
 		}
-		config.enableMultiplexedSessionForPartitionedOps = config.enableMultiplexedSessionForPartitionedOps && config.SessionPoolConfig.enableMultiplexSession
+	} else {
+		config.enableMultiplexedSessionForPartitionedOps = true
 	}
 
+	config.enableMultiplexedSessionForRW = config.SessionPoolConfig.enableMultiplexSession && config.enableMultiplexedSessionForRW
+	config.enableMultiplexedSessionForPartitionedOps = config.SessionPoolConfig.enableMultiplexSession && config.enableMultiplexedSessionForPartitionedOps
+
 	if config.IsExperimentalHost {
 		config.SessionPoolConfig.enableMultiplexSession = true
 		config.enableMultiplexedSessionForRW = true