feat: StreamWriterV2 will attach stream name in the first request in …

…the connection and remove stream name and schema in the following ones.

google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1beta2/StreamWriterV2.java

@@ -296,6 +296,7 @@ public void close() {
    * It takes requests from waiting queue and sends them to server.
    */
   private void appendLoop() {
+    boolean isFirstRequestInConnection = true;
     Deque<AppendRequestAndResponse> localQueue = new LinkedList<AppendRequestAndResponse>();
     while (!waitingQueueDrained()) {
       this.lock.lock();
@@ -322,7 +323,11 @@ private void appendLoop() {
 
       // TODO: Add reconnection here.
       while (!localQueue.isEmpty()) {
-        this.streamConnection.send(localQueue.pollFirst().message);
+        AppendRowsRequest preparedRequest =
+            prepareRequestBasedOnPosition(
+                localQueue.pollFirst().message, isFirstRequestInConnection);
+        this.streamConnection.send(preparedRequest);
+        isFirstRequestInConnection = false;
       }
     }
 
@@ -371,6 +376,18 @@ private void waitForDoneCallback() {
     }
   }
 
+  private AppendRowsRequest prepareRequestBasedOnPosition(
+      AppendRowsRequest original, boolean isFirstRequest) {
+    AppendRowsRequest.Builder requestBuilder = original.toBuilder();
+    if (isFirstRequest) {
+      requestBuilder.setWriteStream(this.streamName);
+    } else {
+      requestBuilder.clearWriteStream();
+      requestBuilder.getProtoRowsBuilder().clearWriterSchema();
+    }
+    return requestBuilder.build();
+  }
+
   private void cleanupInflightRequests() {
     Throwable finalStatus;
     Deque<AppendRequestAndResponse> localQueue = new LinkedList<AppendRequestAndResponse>();

google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1beta2/StreamWriterV2Test.java

@@ -16,6 +16,7 @@
 package com.google.cloud.bigquery.storage.v1beta2;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 
@@ -192,6 +193,19 @@ public void testAppendSuccess() throws Exception {
     }
     assertEquals(appendCount, testBigQueryWrite.getAppendRequests().size());
 
+    for (int i = 0; i < appendCount; i++) {
+      AppendRowsRequest serverRequest = testBigQueryWrite.getAppendRequests().get(i);
+      if (i == 0) {
+        // First request received by server should have schema and stream name.
+        assertTrue(serverRequest.getProtoRows().hasWriterSchema());
+        assertEquals(serverRequest.getWriteStream(), TEST_STREAM);
+      } else {
+        // Following request should not have schema and stream name.
+        assertFalse(serverRequest.getProtoRows().hasWriterSchema());
+        assertEquals(serverRequest.getWriteStream(), "");
+      }
+    }
+
     writer.close();
   }