diff --git a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/BaseBigQueryReadClient.java b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/BaseBigQueryReadClient.java
index 92044d9a4d..b36e10c54f 100644
--- a/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/BaseBigQueryReadClient.java
+++ b/google-cloud-bigquerystorage/src/main/java/com/google/cloud/bigquery/storage/v1/BaseBigQueryReadClient.java
@@ -291,6 +291,7 @@ public final ReadSession createReadSession(
    *           .setParent(ProjectName.of("[PROJECT]").toString())
    *           .setReadSession(ReadSession.newBuilder().build())
    *           .setMaxStreamCount(940837515)
+   *           .setPreferredMinStreamCount(-1905507237)
    *           .build();
    *   ReadSession response = baseBigQueryReadClient.createReadSession(request);
    * }
@@ -333,6 +334,7 @@ public final ReadSession createReadSession(CreateReadSessionRequest request) {
    *           .setParent(ProjectName.of("[PROJECT]").toString())
    *           .setReadSession(ReadSession.newBuilder().build())
    *           .setMaxStreamCount(940837515)
+   *           .setPreferredMinStreamCount(-1905507237)
    *           .build();
    *   ApiFuture<ReadSession> future =
    *       baseBigQueryReadClient.createReadSessionCallable().futureCall(request);
diff --git a/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/BigQueryWriteClientTest.java b/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/BigQueryWriteClientTest.java
index 74d4da41ab..dbe48c243d 100644
--- a/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/BigQueryWriteClientTest.java
+++ b/google-cloud-bigquerystorage/src/test/java/com/google/cloud/bigquery/storage/v1/BigQueryWriteClientTest.java
@@ -177,6 +177,7 @@ public void appendRowsTest() throws Exception {
         AppendRowsResponse.newBuilder()
             .setUpdatedSchema(TableSchema.newBuilder().build())
             .addAllRowErrors(new ArrayList<RowError>())
+            .setWriteStream("writeStream1412231231")
             .build();
     mockBigQueryWrite.addResponse(expectedResponse);
     AppendRowsRequest request =
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsRequest.java b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsRequest.java
index ebafee0778..f5503f40fd 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsRequest.java
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsRequest.java
@@ -26,6 +26,8 @@
  * Due to the nature of AppendRows being a bidirectional streaming RPC, certain
  * parts of the AppendRowsRequest need only be specified for the first request
  * sent each time the gRPC network connection is opened/reopened.
+ * The size of a single AppendRowsRequest must be less than 10 MB in size.
+ * Requests larger than this return an error, typically `INVALID_ARGUMENT`.
  * </pre>
  *
  * Protobuf type {@code google.cloud.bigquery.storage.v1.AppendRowsRequest}
@@ -1827,6 +1829,8 @@ protected Builder newBuilderForType(com.google.protobuf.GeneratedMessageV3.Build
    * Due to the nature of AppendRows being a bidirectional streaming RPC, certain
    * parts of the AppendRowsRequest need only be specified for the first request
    * sent each time the gRPC network connection is opened/reopened.
+   * The size of a single AppendRowsRequest must be less than 10 MB in size.
+   * Requests larger than this return an error, typically `INVALID_ARGUMENT`.
    * </pre>
    *
    * Protobuf type {@code google.cloud.bigquery.storage.v1.AppendRowsRequest}
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponse.java b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponse.java
index 7b4c2c8c9c..23240d2a6e 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponse.java
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponse.java
@@ -39,6 +39,7 @@ private AppendRowsResponse(com.google.protobuf.GeneratedMessageV3.Builder<?> bui
 
   private AppendRowsResponse() {
     rowErrors_ = java.util.Collections.emptyList();
+    writeStream_ = "";
   }
 
   @java.lang.Override
@@ -136,6 +137,13 @@ private AppendRowsResponse(
                       com.google.cloud.bigquery.storage.v1.RowError.parser(), extensionRegistry));
               break;
             }
+          case 42:
+            {
+              java.lang.String s = input.readStringRequireUtf8();
+
+              writeStream_ = s;
+              break;
+            }
           default:
             {
               if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
@@ -1282,6 +1290,57 @@ public com.google.cloud.bigquery.storage.v1.RowErrorOrBuilder getRowErrorsOrBuil
     return rowErrors_.get(index);
   }
 
+  public static final int WRITE_STREAM_FIELD_NUMBER = 5;
+  private volatile java.lang.Object writeStream_;
+  /**
+   *
+   *
+   * <pre>
+   * The target of the append operation. Matches the write_stream in the
+   * corresponding request.
+   * </pre>
+   *
+   * <code>string write_stream = 5;</code>
+   *
+   * @return The writeStream.
+   */
+  @java.lang.Override
+  public java.lang.String getWriteStream() {
+    java.lang.Object ref = writeStream_;
+    if (ref instanceof java.lang.String) {
+      return (java.lang.String) ref;
+    } else {
+      com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
+      java.lang.String s = bs.toStringUtf8();
+      writeStream_ = s;
+      return s;
+    }
+  }
+  /**
+   *
+   *
+   * <pre>
+   * The target of the append operation. Matches the write_stream in the
+   * corresponding request.
+   * </pre>
+   *
+   * <code>string write_stream = 5;</code>
+   *
+   * @return The bytes for writeStream.
+   */
+  @java.lang.Override
+  public com.google.protobuf.ByteString getWriteStreamBytes() {
+    java.lang.Object ref = writeStream_;
+    if (ref instanceof java.lang.String) {
+      com.google.protobuf.ByteString b =
+          com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
+      writeStream_ = b;
+      return b;
+    } else {
+      return (com.google.protobuf.ByteString) ref;
+    }
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -1309,6 +1368,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < rowErrors_.size(); i++) {
       output.writeMessage(4, rowErrors_.get(i));
     }
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(writeStream_)) {
+      com.google.protobuf.GeneratedMessageV3.writeString(output, 5, writeStream_);
+    }
     unknownFields.writeTo(output);
   }
 
@@ -1334,6 +1396,9 @@ public int getSerializedSize() {
     for (int i = 0; i < rowErrors_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(4, rowErrors_.get(i));
     }
+    if (!com.google.protobuf.GeneratedMessageV3.isStringEmpty(writeStream_)) {
+      size += com.google.protobuf.GeneratedMessageV3.computeStringSize(5, writeStream_);
+    }
     size += unknownFields.getSerializedSize();
     memoizedSize = size;
     return size;
@@ -1355,6 +1420,7 @@ public boolean equals(final java.lang.Object obj) {
       if (!getUpdatedSchema().equals(other.getUpdatedSchema())) return false;
     }
     if (!getRowErrorsList().equals(other.getRowErrorsList())) return false;
+    if (!getWriteStream().equals(other.getWriteStream())) return false;
     if (!getResponseCase().equals(other.getResponseCase())) return false;
     switch (responseCase_) {
       case 1:
@@ -1385,6 +1451,8 @@ public int hashCode() {
       hash = (37 * hash) + ROW_ERRORS_FIELD_NUMBER;
       hash = (53 * hash) + getRowErrorsList().hashCode();
     }
+    hash = (37 * hash) + WRITE_STREAM_FIELD_NUMBER;
+    hash = (53 * hash) + getWriteStream().hashCode();
     switch (responseCase_) {
       case 1:
         hash = (37 * hash) + APPEND_RESULT_FIELD_NUMBER;
@@ -1557,6 +1625,8 @@ public Builder clear() {
       } else {
         rowErrorsBuilder_.clear();
       }
+      writeStream_ = "";
+
       responseCase_ = 0;
       response_ = null;
       return this;
@@ -1615,6 +1685,7 @@ public com.google.cloud.bigquery.storage.v1.AppendRowsResponse buildPartial() {
       } else {
         result.rowErrors_ = rowErrorsBuilder_.build();
       }
+      result.writeStream_ = writeStream_;
       result.responseCase_ = responseCase_;
       onBuilt();
       return result;
@@ -1696,6 +1767,10 @@ public Builder mergeFrom(com.google.cloud.bigquery.storage.v1.AppendRowsResponse
           }
         }
       }
+      if (!other.getWriteStream().isEmpty()) {
+        writeStream_ = other.writeStream_;
+        onChanged();
+      }
       switch (other.getResponseCase()) {
         case APPEND_RESULT:
           {
@@ -2899,6 +2974,117 @@ public com.google.cloud.bigquery.storage.v1.RowError.Builder addRowErrorsBuilder
       return rowErrorsBuilder_;
     }
 
+    private java.lang.Object writeStream_ = "";
+    /**
+     *
+     *
+     * <pre>
+     * The target of the append operation. Matches the write_stream in the
+     * corresponding request.
+     * </pre>
+     *
+     * <code>string write_stream = 5;</code>
+     *
+     * @return The writeStream.
+     */
+    public java.lang.String getWriteStream() {
+      java.lang.Object ref = writeStream_;
+      if (!(ref instanceof java.lang.String)) {
+        com.google.protobuf.ByteString bs = (com.google.protobuf.ByteString) ref;
+        java.lang.String s = bs.toStringUtf8();
+        writeStream_ = s;
+        return s;
+      } else {
+        return (java.lang.String) ref;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The target of the append operation. Matches the write_stream in the
+     * corresponding request.
+     * </pre>
+     *
+     * <code>string write_stream = 5;</code>
+     *
+     * @return The bytes for writeStream.
+     */
+    public com.google.protobuf.ByteString getWriteStreamBytes() {
+      java.lang.Object ref = writeStream_;
+      if (ref instanceof String) {
+        com.google.protobuf.ByteString b =
+            com.google.protobuf.ByteString.copyFromUtf8((java.lang.String) ref);
+        writeStream_ = b;
+        return b;
+      } else {
+        return (com.google.protobuf.ByteString) ref;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The target of the append operation. Matches the write_stream in the
+     * corresponding request.
+     * </pre>
+     *
+     * <code>string write_stream = 5;</code>
+     *
+     * @param value The writeStream to set.
+     * @return This builder for chaining.
+     */
+    public Builder setWriteStream(java.lang.String value) {
+      if (value == null) {
+        throw new NullPointerException();
+      }
+
+      writeStream_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The target of the append operation. Matches the write_stream in the
+     * corresponding request.
+     * </pre>
+     *
+     * <code>string write_stream = 5;</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearWriteStream() {
+
+      writeStream_ = getDefaultInstance().getWriteStream();
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The target of the append operation. Matches the write_stream in the
+     * corresponding request.
+     * </pre>
+     *
+     * <code>string write_stream = 5;</code>
+     *
+     * @param value The bytes for writeStream to set.
+     * @return This builder for chaining.
+     */
+    public Builder setWriteStreamBytes(com.google.protobuf.ByteString value) {
+      if (value == null) {
+        throw new NullPointerException();
+      }
+      checkByteStringIsUtf8(value);
+
+      writeStream_ = value;
+      onChanged();
+      return this;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponseOrBuilder.java b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponseOrBuilder.java
index 0226d78642..cfafd12c9d 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponseOrBuilder.java
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/AppendRowsResponseOrBuilder.java
@@ -239,5 +239,32 @@ public interface AppendRowsResponseOrBuilder
    */
   com.google.cloud.bigquery.storage.v1.RowErrorOrBuilder getRowErrorsOrBuilder(int index);
 
+  /**
+   *
+   *
+   * <pre>
+   * The target of the append operation. Matches the write_stream in the
+   * corresponding request.
+   * </pre>
+   *
+   * <code>string write_stream = 5;</code>
+   *
+   * @return The writeStream.
+   */
+  java.lang.String getWriteStream();
+  /**
+   *
+   *
+   * <pre>
+   * The target of the append operation. Matches the write_stream in the
+   * corresponding request.
+   * </pre>
+   *
+   * <code>string write_stream = 5;</code>
+   *
+   * @return The bytes for writeStream.
+   */
+  com.google.protobuf.ByteString getWriteStreamBytes();
+
   public com.google.cloud.bigquery.storage.v1.AppendRowsResponse.ResponseCase getResponseCase();
 }
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequest.java b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequest.java
index 4727bcb074..13336966b2 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequest.java
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequest.java
@@ -98,6 +98,11 @@ private CreateReadSessionRequest(
               maxStreamCount_ = input.readInt32();
               break;
             }
+          case 32:
+            {
+              preferredMinStreamCount_ = input.readInt32();
+              break;
+            }
           default:
             {
               if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
@@ -269,6 +274,30 @@ public int getMaxStreamCount() {
     return maxStreamCount_;
   }
 
+  public static final int PREFERRED_MIN_STREAM_COUNT_FIELD_NUMBER = 4;
+  private int preferredMinStreamCount_;
+  /**
+   *
+   *
+   * <pre>
+   * The minimum preferred stream count. This parameter can be used to inform
+   * the service that there is a desired lower bound on the number of streams.
+   * This is typically a target parallelism of the client (e.g. a Spark
+   * cluster with N-workers would set this to a low multiple of N to ensure
+   * good cluster utilization).
+   * The system will make a best effort to provide at least this number of
+   * streams, but in some cases might provide less.
+   * </pre>
+   *
+   * <code>int32 preferred_min_stream_count = 4;</code>
+   *
+   * @return The preferredMinStreamCount.
+   */
+  @java.lang.Override
+  public int getPreferredMinStreamCount() {
+    return preferredMinStreamCount_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -292,6 +321,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (maxStreamCount_ != 0) {
       output.writeInt32(3, maxStreamCount_);
     }
+    if (preferredMinStreamCount_ != 0) {
+      output.writeInt32(4, preferredMinStreamCount_);
+    }
     unknownFields.writeTo(output);
   }
 
@@ -310,6 +342,9 @@ public int getSerializedSize() {
     if (maxStreamCount_ != 0) {
       size += com.google.protobuf.CodedOutputStream.computeInt32Size(3, maxStreamCount_);
     }
+    if (preferredMinStreamCount_ != 0) {
+      size += com.google.protobuf.CodedOutputStream.computeInt32Size(4, preferredMinStreamCount_);
+    }
     size += unknownFields.getSerializedSize();
     memoizedSize = size;
     return size;
@@ -332,6 +367,7 @@ public boolean equals(final java.lang.Object obj) {
       if (!getReadSession().equals(other.getReadSession())) return false;
     }
     if (getMaxStreamCount() != other.getMaxStreamCount()) return false;
+    if (getPreferredMinStreamCount() != other.getPreferredMinStreamCount()) return false;
     if (!unknownFields.equals(other.unknownFields)) return false;
     return true;
   }
@@ -351,6 +387,8 @@ public int hashCode() {
     }
     hash = (37 * hash) + MAX_STREAM_COUNT_FIELD_NUMBER;
     hash = (53 * hash) + getMaxStreamCount();
+    hash = (37 * hash) + PREFERRED_MIN_STREAM_COUNT_FIELD_NUMBER;
+    hash = (53 * hash) + getPreferredMinStreamCount();
     hash = (29 * hash) + unknownFields.hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -507,6 +545,8 @@ public Builder clear() {
       }
       maxStreamCount_ = 0;
 
+      preferredMinStreamCount_ = 0;
+
       return this;
     }
 
@@ -542,6 +582,7 @@ public com.google.cloud.bigquery.storage.v1.CreateReadSessionRequest buildPartia
         result.readSession_ = readSessionBuilder_.build();
       }
       result.maxStreamCount_ = maxStreamCount_;
+      result.preferredMinStreamCount_ = preferredMinStreamCount_;
       onBuilt();
       return result;
     }
@@ -603,6 +644,9 @@ public Builder mergeFrom(com.google.cloud.bigquery.storage.v1.CreateReadSessionR
       if (other.getMaxStreamCount() != 0) {
         setMaxStreamCount(other.getMaxStreamCount());
       }
+      if (other.getPreferredMinStreamCount() != 0) {
+        setPreferredMinStreamCount(other.getPreferredMinStreamCount());
+      }
       this.mergeUnknownFields(other.unknownFields);
       onChanged();
       return this;
@@ -1035,6 +1079,76 @@ public Builder clearMaxStreamCount() {
       return this;
     }
 
+    private int preferredMinStreamCount_;
+    /**
+     *
+     *
+     * <pre>
+     * The minimum preferred stream count. This parameter can be used to inform
+     * the service that there is a desired lower bound on the number of streams.
+     * This is typically a target parallelism of the client (e.g. a Spark
+     * cluster with N-workers would set this to a low multiple of N to ensure
+     * good cluster utilization).
+     * The system will make a best effort to provide at least this number of
+     * streams, but in some cases might provide less.
+     * </pre>
+     *
+     * <code>int32 preferred_min_stream_count = 4;</code>
+     *
+     * @return The preferredMinStreamCount.
+     */
+    @java.lang.Override
+    public int getPreferredMinStreamCount() {
+      return preferredMinStreamCount_;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The minimum preferred stream count. This parameter can be used to inform
+     * the service that there is a desired lower bound on the number of streams.
+     * This is typically a target parallelism of the client (e.g. a Spark
+     * cluster with N-workers would set this to a low multiple of N to ensure
+     * good cluster utilization).
+     * The system will make a best effort to provide at least this number of
+     * streams, but in some cases might provide less.
+     * </pre>
+     *
+     * <code>int32 preferred_min_stream_count = 4;</code>
+     *
+     * @param value The preferredMinStreamCount to set.
+     * @return This builder for chaining.
+     */
+    public Builder setPreferredMinStreamCount(int value) {
+
+      preferredMinStreamCount_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The minimum preferred stream count. This parameter can be used to inform
+     * the service that there is a desired lower bound on the number of streams.
+     * This is typically a target parallelism of the client (e.g. a Spark
+     * cluster with N-workers would set this to a low multiple of N to ensure
+     * good cluster utilization).
+     * The system will make a best effort to provide at least this number of
+     * streams, but in some cases might provide less.
+     * </pre>
+     *
+     * <code>int32 preferred_min_stream_count = 4;</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearPreferredMinStreamCount() {
+
+      preferredMinStreamCount_ = 0;
+      onChanged();
+      return this;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequestOrBuilder.java b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequestOrBuilder.java
index 39836f0e4a..a878ce7c8f 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequestOrBuilder.java
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/CreateReadSessionRequestOrBuilder.java
@@ -115,4 +115,23 @@ public interface CreateReadSessionRequestOrBuilder
    * @return The maxStreamCount.
    */
   int getMaxStreamCount();
+
+  /**
+   *
+   *
+   * <pre>
+   * The minimum preferred stream count. This parameter can be used to inform
+   * the service that there is a desired lower bound on the number of streams.
+   * This is typically a target parallelism of the client (e.g. a Spark
+   * cluster with N-workers would set this to a low multiple of N to ensure
+   * good cluster utilization).
+   * The system will make a best effort to provide at least this number of
+   * streams, but in some cases might provide less.
+   * </pre>
+   *
+   * <code>int32 preferred_min_stream_count = 4;</code>
+   *
+   * @return The preferredMinStreamCount.
+   */
+  int getPreferredMinStreamCount();
 }
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/StorageProto.java b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/StorageProto.java
index 3c8e5fa627..41a86d47f0 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/StorageProto.java
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/java/com/google/cloud/bigquery/storage/v1/StorageProto.java
@@ -137,157 +137,159 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "igquery/storage/v1/table.proto\032\037google/p"
           + "rotobuf/timestamp.proto\032\036google/protobuf"
           + "/wrappers.proto\032\027google/rpc/status.proto"
-          + "\"\303\001\n\030CreateReadSessionRequest\022C\n\006parent\030"
+          + "\"\347\001\n\030CreateReadSessionRequest\022C\n\006parent\030"
           + "\001 \001(\tB3\340A\002\372A-\n+cloudresourcemanager.goog"
           + "leapis.com/Project\022H\n\014read_session\030\002 \001(\013"
           + "2-.google.cloud.bigquery.storage.v1.Read"
-          + "SessionB\003\340A\002\022\030\n\020max_stream_count\030\003 \001(\005\"i"
-          + "\n\017ReadRowsRequest\022F\n\013read_stream\030\001 \001(\tB1"
-          + "\340A\002\372A+\n)bigquerystorage.googleapis.com/R"
-          + "eadStream\022\016\n\006offset\030\002 \001(\003\")\n\rThrottleSta"
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+          + "jects/*/datasets/*/tables/*/streams/*}:\001"
+          + "*\332A\014write_stream\032\260\001\312A\036bigquerystorage.go"
+          + "ogleapis.com\322A\213\001https://www.googleapis.c"
+          + "om/auth/bigquery,https://www.googleapis."
+          + "com/auth/bigquery.insertdata,https://www"
+          + ".googleapis.com/auth/cloud-platformB\235\002\n$"
+          + "com.google.cloud.bigquery.storage.v1B\014St"
+          + "orageProtoP\001ZGgoogle.golang.org/genproto"
+          + "/googleapis/cloud/bigquery/storage/v1;st"
+          + "orage\252\002 Google.Cloud.BigQuery.Storage.V1"
+          + "\312\002 Google\\Cloud\\BigQuery\\Storage\\V1\352AU\n\035"
+          + "bigquery.googleapis.com/Table\0224projects/"
+          + "{project}/datasets/{dataset}/tables/{tab"
+          + "le}b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
@@ -312,7 +314,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_cloud_bigquery_storage_v1_CreateReadSessionRequest_descriptor,
             new java.lang.String[] {
-              "Parent", "ReadSession", "MaxStreamCount",
+              "Parent", "ReadSession", "MaxStreamCount", "PreferredMinStreamCount",
             });
     internal_static_google_cloud_bigquery_storage_v1_ReadRowsRequest_descriptor =
         getDescriptor().getMessageTypes().get(1);
@@ -412,7 +414,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_cloud_bigquery_storage_v1_AppendRowsResponse_descriptor,
             new java.lang.String[] {
-              "AppendResult", "Error", "UpdatedSchema", "RowErrors", "Response",
+              "AppendResult", "Error", "UpdatedSchema", "RowErrors", "WriteStream", "Response",
             });
     internal_static_google_cloud_bigquery_storage_v1_AppendRowsResponse_AppendResult_descriptor =
         internal_static_google_cloud_bigquery_storage_v1_AppendRowsResponse_descriptor
diff --git a/proto-google-cloud-bigquerystorage-v1/src/main/proto/google/cloud/bigquery/storage/v1/storage.proto b/proto-google-cloud-bigquerystorage-v1/src/main/proto/google/cloud/bigquery/storage/v1/storage.proto
index f3c974c646..e0b25c1afe 100644
--- a/proto-google-cloud-bigquerystorage-v1/src/main/proto/google/cloud/bigquery/storage/v1/storage.proto
+++ b/proto-google-cloud-bigquerystorage-v1/src/main/proto/google/cloud/bigquery/storage/v1/storage.proto
@@ -256,6 +256,16 @@ message CreateReadSessionRequest {
   // determine an upper bound OR set this a size for the maximum "units of work"
   // it can gracefully handle.
   int32 max_stream_count = 3;
+
+  // The minimum preferred stream count. This parameter can be used to inform
+  // the service that there is a desired lower bound on the number of streams.
+  // This is typically a target parallelism of the client (e.g. a Spark
+  // cluster with N-workers would set this to a low multiple of N to ensure
+  // good cluster utilization).
+  //
+  // The system will make a best effort to provide at least this number of
+  // streams, but in some cases might provide less.
+  int32 preferred_min_stream_count = 4;
 }
 
 // Request message for `ReadRows`.
@@ -395,6 +405,9 @@ message CreateWriteStreamRequest {
 // Due to the nature of AppendRows being a bidirectional streaming RPC, certain
 // parts of the AppendRowsRequest need only be specified for the first request
 // sent each time the gRPC network connection is opened/reopened.
+//
+// The size of a single AppendRowsRequest must be less than 10 MB in size.
+// Requests larger than this return an error, typically `INVALID_ARGUMENT`.
 message AppendRowsRequest {
   // ProtoData contains the data rows and schema when constructing append
   // requests.
@@ -495,6 +508,10 @@ message AppendRowsResponse {
   // appended. The API will return row level error info, so that the caller can
   // remove the bad rows and retry the request.
   repeated RowError row_errors = 4;
+
+  // The target of the append operation. Matches the write_stream in the
+  // corresponding request.
+  string write_stream = 5;
 }
 
 // Request message for `GetWriteStreamRequest`.