Merge branch 'main' into replace-exec-options-with-connection-variables

Author: olavloite

README.md

@@ -103,10 +103,10 @@ tx.QueryContext(ctx, "SELECT SingerId, Name FROM Singers WHERE SingerId = ?", 12
 
 ## Transactions
 
-- Read-write transactions always uses the strongest isolation level and ignore the user-specified level.
+- Read-write transactions support isolation levels `Serializable`, `Snapshot` and `RepeatableRead`.
 - Read-only transactions do strong-reads by default. Read-only transactions must be ended by calling
   either Commit or Rollback. Calling either of these methods will end the current read-only
-  transaction and return the session that is used to the session pool.
+  transaction.
 
 ```go
 tx, err := db.BeginTx(ctx, &sql.TxOptions{}) // Read-write transaction.
@@ -226,6 +226,11 @@ $ gcloud beta emulators spanner start
 $ export SPANNER_EMULATOR_HOST=localhost:9010
 ```
 
+### Automatically Create Instance and Database on the Emulator
+You can also add the `autoConfigEmulator=true` option to the connection string. This will instruct the driver
+to connect to the Spanner emulator, and to automatically create the Spanner instance and database on the
+emulator. See [examples/emulator](examples/emulator) for a working example.
+
 ## Spanner PostgreSQL Interface
 
 This driver works with both Spanner GoogleSQL and PostgreSQL dialects.

driver.go

@@ -86,8 +86,8 @@ var noopLogger = slog.New(slog.NewTextHandler(io.Discard, &slog.HandlerOptions{L
 //     The default is false
 //     - enableEndToEndTracing: Boolean that indicates if end-to-end tracing is enabled
 //     The default is false
-//     - minSessions: The minimum number of sessions in the backing session pool. The default is 100.
-//     - maxSessions: The maximum number of sessions in the backing session pool. The default is 400.
+//     - minSessions (DEPRECATED): The minimum number of sessions in the backing session pool. The default is 100. This option is deprecated, as the driver by default uses a single multiplexed session for all operations.
+//     - maxSessions (DEPRECATED): The maximum number of sessions in the backing session pool. The default is 400. This option is deprecated, as the driver by default uses a single multiplexed session for all operations.
 //     - numChannels: The number of gRPC channels to use to communicate with Cloud Spanner. The default is 4.
 //     - optimizerVersion: Sets the default query optimizer version to use for this connection.
 //     - optimizerStatisticsPackage: Sets the default query optimizer statistic package to use for this connection.

driver_with_mockserver_test.go

@@ -3444,7 +3444,8 @@ func TestMaxSessions(t *testing.T) {
 }
 
 func TestClientReuse(t *testing.T) {
-	t.Parallel()
+	// MinSessions only has an effect if we are not using multiplexed sessions.
+	t.Setenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS", "false")
 
 	ctx := context.Background()
 	db, server, teardown := setupTestDBConnectionWithParams(t, "minSessions=2")
@@ -3502,7 +3503,8 @@ func TestClientReuse(t *testing.T) {
 }
 
 func TestStressClientReuse(t *testing.T) {
-	t.Parallel()
+	// MinSessions only has an effect if we are not using multiplexed sessions.
+	t.Setenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS", "false")
 
 	ctx := context.Background()
 	_, server, teardown := setupTestDBConnection(t)
@@ -4288,7 +4290,8 @@ func TestTag_RunTransactionWithOptions_IsNotSticky(t *testing.T) {
 }
 
 func TestMaxIdleConnectionsNonZero(t *testing.T) {
-	t.Parallel()
+	// MinSessions only has an effect if we are not using multiplexed sessions.
+	t.Setenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS", "false")
 
 	// Set MinSessions=1, so we can use the number of BatchCreateSessions requests as an indication
 	// of the number of clients that was created.
@@ -4310,7 +4313,8 @@ func TestMaxIdleConnectionsNonZero(t *testing.T) {
 }
 
 func TestMaxIdleConnectionsZero(t *testing.T) {
-	t.Parallel()
+	// MinSessions only has an effect if we are not using multiplexed sessions.
+	t.Setenv("GOOGLE_CLOUD_SPANNER_MULTIPLEXED_SESSIONS", "false")
 
 	// Set MinSessions=1, so we can use the number of BatchCreateSessions requests as an indication
 	// of the number of clients that was created.
@@ -4356,9 +4360,16 @@ func openAndCloseConn(t *testing.T, db *sql.DB) {
 func TestCannotReuseClosedConnector(t *testing.T) {
 	// Note: This test cannot be parallel, as it inspects the size of the shared
 	// map of connectors in the driver. There is no guarantee how many connectors
-	// will be open when the test is running, if there are also other tests running
+	// will be open when the test is running, if there are other tests running
 	// in parallel.
 
+	// Make sure we start with an empty list of connectors. This cleans up connectors
+	// that other tests might have created, but not cleaned up.
+	connectors := spannerDriver.connectors
+	for _, connector := range connectors {
+		_ = connector.Close()
+	}
+
 	db, _, teardown := setupTestDBConnection(t)
 	defer teardown()
 
@@ -4368,9 +4379,8 @@ func TestCannotReuseClosedConnector(t *testing.T) {
 		t.Fatalf("failed to get a connection: %v", err)
 	}
 	_ = conn.Close()
-	connectors := db.Driver().(*Driver).connectors
 	if g, w := len(connectors), 1; g != w {
-		t.Fatal("underlying connector has not been created")
+		t.Fatalf("underlying connector count mismatch\n Got: %v\nWant: %v", g, w)
 	}
 	var connector *connector
 	for _, v := range connectors {