feat(bigquery): add zero-copy queryArrow API for Arrow VectorSchemaRoot streaming

java-bigquery/google-cloud-bigquery/pom.xml

@@ -120,6 +120,15 @@
       <artifactId>arrow-memory-netty</artifactId>
     </dependency>
 
+    <dependency>
+      <groupId>com.google.api</groupId>
+      <artifactId>gax-grpc</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>io.grpc</groupId>
+      <artifactId>grpc-api</artifactId>
+    </dependency>
+
     <dependency>
       <groupId>com.google.errorprone</groupId>
       <artifactId>error_prone_annotations</artifactId>

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/ArrowDeserializer.java

@@ -50,6 +50,16 @@ private static class AllocatorHolder {
     private static final BufferAllocator ALLOCATOR = new RootAllocator(Long.MAX_VALUE);
   }
 
+  /**
+   * Creates a new child buffer allocator with the given name.
+   *
+   * @param name the child allocator name
+   * @return a new child buffer allocator
+   */
+  static BufferAllocator createChildAllocator(String name) {
+    return AllocatorHolder.ALLOCATOR.newChildAllocator(name, 0, Long.MAX_VALUE);
+  }
+
   /**
    * Instantiates a new {@link VectorSchemaRoot} for the given Arrow schema using vectors allocated
    * from the provided child allocator, ensuring LIFO cleanup if an error occurs during

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/ArrowQueryResult.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2026 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
+ *
+ *       http://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.
+ */
+
+package com.google.cloud.bigquery;
+
+import com.google.api.core.BetaApi;
+import org.apache.arrow.vector.VectorSchemaRoot;
+import org.apache.arrow.vector.types.pojo.Schema;
+
+/**
+ * <b>[Beta]</b> A query result container providing zero-copy access to Apache Arrow {@link
+ * VectorSchemaRoot} batches.
+ *
+ * <p>Implementations manage direct off-heap native memory buffers. Callers must invoke {@link
+ * #close()} (idiomatically via a {@code try-with-resources} block) to ensure native allocations and
+ * underlying gRPC streaming channels are deterministically released.
+ */
+@BetaApi
+public interface ArrowQueryResult extends AutoCloseable, Iterable<VectorSchemaRoot> {
+
+  /** Returns the Apache Arrow schema of the result vectors. */
+  Schema getArrowSchema();
+
+  /**
+   * Returns the job ID associated with the query execution, or {@code null} if no job was created
+   * (e.g. when optional job creation was used).
+   */
+  JobId getJobId();
+
+  /** Returns the query ID associated with the query execution, or {@code null} if unavailable. */
+  String getQueryId();
+
+  /**
+   * Returns the reason a job was created when optional job creation was requested, or {@code null}
+   * if no job was created or if the query ran via the fallback path.
+   */
+  JobCreationReason getJobCreationReason();
+
+  /** Returns the total number of rows across all batches if known, or {@code -1} if unknown. */
+  long getTotalRows();
+
+  /**
+   * Releases underlying direct off-heap memory allocations and closes any active stream channels.
+   */
+  @Override
+  void close();
+}