chore: use existing transaction for analyze in batch (#2737)

DML batches in a transaction are allowed to execute analyzeUpdate.
PGAdapter should use this transaction instead of creating a separate
transaction in such cases to reduce the number of round-trips.

src/main/java/com/google/cloud/spanner/pgadapter/statements/BackendConnection.java

@@ -415,7 +415,7 @@ StatementResult analyzeOrExecute(Statement statement) {
           // We handle one very specific use case here to prevent unnecessary problems: If the user
           // has started a DML batch and is then analyzing an update statement (probably a prepared
           // statement), then we use a separate transaction for that.
-          if (spannerConnection.isDmlBatchActive()) {
+          if (spannerConnection.isDmlBatchActive() && !spannerConnection.isInTransaction()) {
             final Statement statementToAnalyze = statement;
             resultSet =
                 spannerConnection

src/test/java/com/google/cloud/spanner/pgadapter/JdbcSimpleModeMockServerTest.java

@@ -32,6 +32,7 @@
 import com.google.spanner.v1.CommitRequest;
 import com.google.spanner.v1.ExecuteSqlRequest;
 import com.google.spanner.v1.ExecuteSqlRequest.QueryMode;
+import com.google.spanner.v1.ResultSetStats;
 import com.google.spanner.v1.RollbackRequest;
 import com.google.spanner.v1.TypeCode;
 import io.grpc.Status;
@@ -873,4 +874,36 @@ public void testImplicitBatchOfClientSideStatements() throws SQLException {
       }
     }
   }
+
+  @Test
+  public void testPrepareInDmlBatch() throws SQLException {
+    String sql = "insert into test (id, value) values ($1, $2)";
+    mockSpanner.putStatementResult(
+        StatementResult.query(
+            com.google.cloud.spanner.Statement.of(sql),
+            com.google.spanner.v1.ResultSet.newBuilder()
+                .setMetadata(
+                    createParameterTypesMetadata(ImmutableList.of(TypeCode.INT64, TypeCode.STRING)))
+                .setStats(ResultSetStats.getDefaultInstance())
+                .build()));
+    mockSpanner.putStatementResult(
+        StatementResult.update(
+            com.google.cloud.spanner.Statement.newBuilder(sql)
+                .bind("p1")
+                .to(1L)
+                .bind("p2")
+                .to("one")
+                .build(),
+            1L));
+
+    try (Connection connection = DriverManager.getConnection(createUrl());
+        Statement statement = connection.createStatement()) {
+      statement.execute("begin");
+      statement.execute("start batch dml");
+      statement.execute("prepare foo as insert into test (id, value) values ($1, $2)");
+      statement.execute("execute foo (1, 'one')");
+      statement.execute("run batch");
+      statement.execute("commit");
+    }
+  }
 }

src/test/java/com/google/cloud/spanner/pgadapter/php/pdo/PdoMockServerTest.java

@@ -815,6 +815,34 @@ public void testBatchDml() throws Exception {
     assertEquals(2, request.getStatementsCount());
   }
 
+  @Test
+  public void testBatchDmlInTransaction() throws Exception {
+    String sql = "insert into my_table (id, value) values ($1, $2)";
+    mockSpanner.putStatementResult(
+        StatementResult.query(
+            Statement.of(sql),
+            ResultSet.newBuilder()
+                .setMetadata(
+                    createParameterTypesMetadata(ImmutableList.of(TypeCode.INT64, TypeCode.STRING)))
+                .setStats(ResultSetStats.getDefaultInstance())
+                .build()));
+    mockSpanner.putStatementResult(
+        StatementResult.update(
+            Statement.newBuilder(sql).bind("p1").to(1L).bind("p2").to("One").build(), 1L));
+    mockSpanner.putStatementResult(
+        StatementResult.update(
+            Statement.newBuilder(sql).bind("p1").to(2L).bind("p2").to("Two").build(), 1L));
+
+    String actualOutput = execute("batch_dml_in_transaction");
+    String expectedOutput = "Inserted two rows\n";
+    assertEquals(expectedOutput, actualOutput);
+
+    assertEquals(1, mockSpanner.countRequestsOfType(ExecuteBatchDmlRequest.class));
+    ExecuteBatchDmlRequest request =
+        mockSpanner.getRequestsOfType(ExecuteBatchDmlRequest.class).get(0);
+    assertEquals(2, request.getStatementsCount());
+  }
+
   @Test
   public void testBatchDdl() throws Exception {
     addDdlResponseToSpannerAdmin();

src/test/php/pdo/pdo_test.php

@@ -286,6 +286,23 @@ function batch_dml($dsn): void
     $connection = null;
 }
 
+function batch_dml_in_transaction($dsn): void
+{
+    $connection = new PDO($dsn);
+    $connection->beginTransaction();
+    $connection->exec("START BATCH DML");
+    $statement = $connection->prepare("insert into my_table (id, value) values (:id, :value)");
+    $statement->execute(["id" => 1, "value" => "One"]);
+    $statement->execute(["id" => 2, "value" => "Two"]);
+    $connection->exec("RUN BATCH");
+    $connection->commit();
+
+    print("Inserted two rows\n");
+
+    $statement = null;
+    $connection = null;
+}
+
 function batch_ddl($dsn): void
 {
     $connection = new PDO($dsn);