diff --git a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java
index 46b124968c..2c430faaad 100644
--- a/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java
+++ b/google-cloud-spanner/src/main/java/com/google/cloud/spanner/v1/SpannerClient.java
@@ -724,6 +724,11 @@ public final UnaryCallable<BeginTransactionRequest, Transaction> beginTransactio
    * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt the transaction from the
    * beginning, re-using the same session.
    *
+   * <p>On very rare occasions, `Commit` might return `UNKNOWN`. This can happen, for example, if
+   * the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost
+   * track of the transaction outcome and we recommend that you perform another read from the
+   * database to see the state of things as they are now.
+   *
    * @param session Required. The session in which the transaction to be committed is running.
    * @param transactionId Commit a previously-started transaction.
    * @param mutations The mutations to be executed when this transaction commits. All mutations are
@@ -751,6 +756,11 @@ public final CommitResponse commit(
    * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt the transaction from the
    * beginning, re-using the same session.
    *
+   * <p>On very rare occasions, `Commit` might return `UNKNOWN`. This can happen, for example, if
+   * the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost
+   * track of the transaction outcome and we recommend that you perform another read from the
+   * database to see the state of things as they are now.
+   *
    * @param session Required. The session in which the transaction to be committed is running.
    * @param singleUseTransaction Execute mutations in a temporary transaction. Note that unlike
    *     commit of a previously-started transaction, commit with a temporary transaction is
@@ -784,6 +794,11 @@ public final CommitResponse commit(
    * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt the transaction from the
    * beginning, re-using the same session.
    *
+   * <p>On very rare occasions, `Commit` might return `UNKNOWN`. This can happen, for example, if
+   * the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost
+   * track of the transaction outcome and we recommend that you perform another read from the
+   * database to see the state of things as they are now.
+   *
    * @param session Required. The session in which the transaction to be committed is running.
    * @param transactionId Commit a previously-started transaction.
    * @param mutations The mutations to be executed when this transaction commits. All mutations are
@@ -811,6 +826,11 @@ public final CommitResponse commit(
    * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt the transaction from the
    * beginning, re-using the same session.
    *
+   * <p>On very rare occasions, `Commit` might return `UNKNOWN`. This can happen, for example, if
+   * the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost
+   * track of the transaction outcome and we recommend that you perform another read from the
+   * database to see the state of things as they are now.
+   *
    * @param session Required. The session in which the transaction to be committed is running.
    * @param singleUseTransaction Execute mutations in a temporary transaction. Note that unlike
    *     commit of a previously-started transaction, commit with a temporary transaction is
@@ -844,6 +864,11 @@ public final CommitResponse commit(
    * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt the transaction from the
    * beginning, re-using the same session.
    *
+   * <p>On very rare occasions, `Commit` might return `UNKNOWN`. This can happen, for example, if
+   * the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost
+   * track of the transaction outcome and we recommend that you perform another read from the
+   * database to see the state of things as they are now.
+   *
    * @param request The request object containing all of the parameters for the API call.
    * @throws com.google.api.gax.rpc.ApiException if the remote call fails
    */
@@ -861,6 +886,11 @@ public final CommitResponse commit(CommitRequest request) {
    * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt the transaction from the
    * beginning, re-using the same session.
    *
+   * <p>On very rare occasions, `Commit` might return `UNKNOWN`. This can happen, for example, if
+   * the client job experiences a 1+ hour networking failure. At that point, Cloud Spanner has lost
+   * track of the transaction outcome and we recommend that you perform another read from the
+   * database to see the state of things as they are now.
+   *
    * <p>Sample code:
    */
   public final UnaryCallable<CommitRequest, CommitResponse> commitCallable() {
diff --git a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java
index a31cc5f2a1..0ee0e706d1 100644
--- a/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java
+++ b/google-cloud-spanner/src/test/java/com/google/cloud/spanner/v1/SpannerClientTest.java
@@ -954,7 +954,10 @@ public void beginTransactionExceptionTest2() throws Exception {
   @Test
   public void commitTest() throws Exception {
     CommitResponse expectedResponse =
-        CommitResponse.newBuilder().setCommitTimestamp(Timestamp.newBuilder().build()).build();
+        CommitResponse.newBuilder()
+            .setCommitTimestamp(Timestamp.newBuilder().build())
+            .setCommitStats(CommitResponse.CommitStats.newBuilder().build())
+            .build();
     mockSpanner.addResponse(expectedResponse);
 
     SessionName session = SessionName.of("[PROJECT]", "[INSTANCE]", "[DATABASE]", "[SESSION]");
@@ -996,7 +999,10 @@ public void commitExceptionTest() throws Exception {
   @Test
   public void commitTest2() throws Exception {
     CommitResponse expectedResponse =
-        CommitResponse.newBuilder().setCommitTimestamp(Timestamp.newBuilder().build()).build();
+        CommitResponse.newBuilder()
+            .setCommitTimestamp(Timestamp.newBuilder().build())
+            .setCommitStats(CommitResponse.CommitStats.newBuilder().build())
+            .build();
     mockSpanner.addResponse(expectedResponse);
 
     SessionName session = SessionName.of("[PROJECT]", "[INSTANCE]", "[DATABASE]", "[SESSION]");
@@ -1038,7 +1044,10 @@ public void commitExceptionTest2() throws Exception {
   @Test
   public void commitTest3() throws Exception {
     CommitResponse expectedResponse =
-        CommitResponse.newBuilder().setCommitTimestamp(Timestamp.newBuilder().build()).build();
+        CommitResponse.newBuilder()
+            .setCommitTimestamp(Timestamp.newBuilder().build())
+            .setCommitStats(CommitResponse.CommitStats.newBuilder().build())
+            .build();
     mockSpanner.addResponse(expectedResponse);
 
     String session = "session1984987798";
@@ -1080,7 +1089,10 @@ public void commitExceptionTest3() throws Exception {
   @Test
   public void commitTest4() throws Exception {
     CommitResponse expectedResponse =
-        CommitResponse.newBuilder().setCommitTimestamp(Timestamp.newBuilder().build()).build();
+        CommitResponse.newBuilder()
+            .setCommitTimestamp(Timestamp.newBuilder().build())
+            .setCommitStats(CommitResponse.CommitStats.newBuilder().build())
+            .build();
     mockSpanner.addResponse(expectedResponse);
 
     String session = "session1984987798";
diff --git a/grpc-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerGrpc.java b/grpc-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerGrpc.java
index 2ea1647918..52e4daaaf1 100644
--- a/grpc-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerGrpc.java
+++ b/grpc-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerGrpc.java
@@ -924,6 +924,11 @@ public void beginTransaction(
      * transactions. However, it can also happen for a variety of other
      * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt
      * the transaction from the beginning, re-using the same session.
+     * On very rare occasions, `Commit` might return `UNKNOWN`. This can happen,
+     * for example, if the client job experiences a 1+ hour networking failure.
+     * At that point, Cloud Spanner has lost track of the transaction outcome and
+     * we recommend that you perform another read from the database to see the
+     * state of things as they are now.
      * </pre>
      */
     public void commit(
@@ -1357,6 +1362,11 @@ public void beginTransaction(
      * transactions. However, it can also happen for a variety of other
      * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt
      * the transaction from the beginning, re-using the same session.
+     * On very rare occasions, `Commit` might return `UNKNOWN`. This can happen,
+     * for example, if the client job experiences a 1+ hour networking failure.
+     * At that point, Cloud Spanner has lost track of the transaction outcome and
+     * we recommend that you perform another read from the database to see the
+     * state of things as they are now.
      * </pre>
      */
     public void commit(
@@ -1663,6 +1673,11 @@ public com.google.spanner.v1.Transaction beginTransaction(
      * transactions. However, it can also happen for a variety of other
      * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt
      * the transaction from the beginning, re-using the same session.
+     * On very rare occasions, `Commit` might return `UNKNOWN`. This can happen,
+     * for example, if the client job experiences a 1+ hour networking failure.
+     * At that point, Cloud Spanner has lost track of the transaction outcome and
+     * we recommend that you perform another read from the database to see the
+     * state of things as they are now.
      * </pre>
      */
     public com.google.spanner.v1.CommitResponse commit(
@@ -1932,6 +1947,11 @@ public com.google.common.util.concurrent.ListenableFuture<com.google.spanner.v1.
      * transactions. However, it can also happen for a variety of other
      * reasons. If `Commit` returns `ABORTED`, the caller should re-attempt
      * the transaction from the beginning, re-using the same session.
+     * On very rare occasions, `Commit` might return `UNKNOWN`. This can happen,
+     * for example, if the client job experiences a 1+ hour networking failure.
+     * At that point, Cloud Spanner has lost track of the transaction outcome and
+     * we recommend that you perform another read from the database to see the
+     * state of things as they are now.
      * </pre>
      */
     public com.google.common.util.concurrent.ListenableFuture<com.google.spanner.v1.CommitResponse>
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java
index f322ec04c0..1ba7b235bb 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequest.java
@@ -111,6 +111,11 @@ private CommitRequest(
                   input.readMessage(com.google.spanner.v1.Mutation.parser(), extensionRegistry));
               break;
             }
+          case 40:
+            {
+              returnCommitStats_ = input.readBool();
+              break;
+            }
           default:
             {
               if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
@@ -422,6 +427,26 @@ public com.google.spanner.v1.MutationOrBuilder getMutationsOrBuilder(int index)
     return mutations_.get(index);
   }
 
+  public static final int RETURN_COMMIT_STATS_FIELD_NUMBER = 5;
+  private boolean returnCommitStats_;
+  /**
+   *
+   *
+   * <pre>
+   * If `true`, then statistics related to the transaction will be included in
+   * the [CommitResponse][google.spanner.v1.CommitResponse.commit_stats]. Default value is
+   * `false`.
+   * </pre>
+   *
+   * <code>bool return_commit_stats = 5;</code>
+   *
+   * @return The returnCommitStats.
+   */
+  @java.lang.Override
+  public boolean getReturnCommitStats() {
+    return returnCommitStats_;
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -448,6 +473,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     for (int i = 0; i < mutations_.size(); i++) {
       output.writeMessage(4, mutations_.get(i));
     }
+    if (returnCommitStats_ != false) {
+      output.writeBool(5, returnCommitStats_);
+    }
     unknownFields.writeTo(output);
   }
 
@@ -473,6 +501,9 @@ public int getSerializedSize() {
     for (int i = 0; i < mutations_.size(); i++) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(4, mutations_.get(i));
     }
+    if (returnCommitStats_ != false) {
+      size += com.google.protobuf.CodedOutputStream.computeBoolSize(5, returnCommitStats_);
+    }
     size += unknownFields.getSerializedSize();
     memoizedSize = size;
     return size;
@@ -490,6 +521,7 @@ public boolean equals(final java.lang.Object obj) {
 
     if (!getSession().equals(other.getSession())) return false;
     if (!getMutationsList().equals(other.getMutationsList())) return false;
+    if (getReturnCommitStats() != other.getReturnCommitStats()) return false;
     if (!getTransactionCase().equals(other.getTransactionCase())) return false;
     switch (transactionCase_) {
       case 2:
@@ -518,6 +550,8 @@ public int hashCode() {
       hash = (37 * hash) + MUTATIONS_FIELD_NUMBER;
       hash = (53 * hash) + getMutationsList().hashCode();
     }
+    hash = (37 * hash) + RETURN_COMMIT_STATS_FIELD_NUMBER;
+    hash = (53 * hash) + com.google.protobuf.Internal.hashBoolean(getReturnCommitStats());
     switch (transactionCase_) {
       case 2:
         hash = (37 * hash) + TRANSACTION_ID_FIELD_NUMBER;
@@ -684,6 +718,8 @@ public Builder clear() {
       } else {
         mutationsBuilder_.clear();
       }
+      returnCommitStats_ = false;
+
       transactionCase_ = 0;
       transaction_ = null;
       return this;
@@ -733,6 +769,7 @@ public com.google.spanner.v1.CommitRequest buildPartial() {
       } else {
         result.mutations_ = mutationsBuilder_.build();
       }
+      result.returnCommitStats_ = returnCommitStats_;
       result.transactionCase_ = transactionCase_;
       onBuilt();
       return result;
@@ -814,6 +851,9 @@ public Builder mergeFrom(com.google.spanner.v1.CommitRequest other) {
           }
         }
       }
+      if (other.getReturnCommitStats() != false) {
+        setReturnCommitStats(other.getReturnCommitStats());
+      }
       switch (other.getTransactionCase()) {
         case TRANSACTION_ID:
           {
@@ -1712,6 +1752,64 @@ public java.util.List<com.google.spanner.v1.Mutation.Builder> getMutationsBuilde
       return mutationsBuilder_;
     }
 
+    private boolean returnCommitStats_;
+    /**
+     *
+     *
+     * <pre>
+     * If `true`, then statistics related to the transaction will be included in
+     * the [CommitResponse][google.spanner.v1.CommitResponse.commit_stats]. Default value is
+     * `false`.
+     * </pre>
+     *
+     * <code>bool return_commit_stats = 5;</code>
+     *
+     * @return The returnCommitStats.
+     */
+    @java.lang.Override
+    public boolean getReturnCommitStats() {
+      return returnCommitStats_;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If `true`, then statistics related to the transaction will be included in
+     * the [CommitResponse][google.spanner.v1.CommitResponse.commit_stats]. Default value is
+     * `false`.
+     * </pre>
+     *
+     * <code>bool return_commit_stats = 5;</code>
+     *
+     * @param value The returnCommitStats to set.
+     * @return This builder for chaining.
+     */
+    public Builder setReturnCommitStats(boolean value) {
+
+      returnCommitStats_ = value;
+      onChanged();
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * If `true`, then statistics related to the transaction will be included in
+     * the [CommitResponse][google.spanner.v1.CommitResponse.commit_stats]. Default value is
+     * `false`.
+     * </pre>
+     *
+     * <code>bool return_commit_stats = 5;</code>
+     *
+     * @return This builder for chaining.
+     */
+    public Builder clearReturnCommitStats() {
+
+      returnCommitStats_ = false;
+      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-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java
index bb0f6c6acd..a32fa4b439 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitRequestOrBuilder.java
@@ -185,5 +185,20 @@ public interface CommitRequestOrBuilder
    */
   com.google.spanner.v1.MutationOrBuilder getMutationsOrBuilder(int index);
 
+  /**
+   *
+   *
+   * <pre>
+   * If `true`, then statistics related to the transaction will be included in
+   * the [CommitResponse][google.spanner.v1.CommitResponse.commit_stats]. Default value is
+   * `false`.
+   * </pre>
+   *
+   * <code>bool return_commit_stats = 5;</code>
+   *
+   * @return The returnCommitStats.
+   */
+  boolean getReturnCommitStats();
+
   public com.google.spanner.v1.CommitRequest.TransactionCase getTransactionCase();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java
index 2877285845..320d165cf9 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponse.java
@@ -81,6 +81,22 @@ private CommitResponse(
                 commitTimestamp_ = subBuilder.buildPartial();
               }
 
+              break;
+            }
+          case 18:
+            {
+              com.google.spanner.v1.CommitResponse.CommitStats.Builder subBuilder = null;
+              if (commitStats_ != null) {
+                subBuilder = commitStats_.toBuilder();
+              }
+              commitStats_ =
+                  input.readMessage(
+                      com.google.spanner.v1.CommitResponse.CommitStats.parser(), extensionRegistry);
+              if (subBuilder != null) {
+                subBuilder.mergeFrom(commitStats_);
+                commitStats_ = subBuilder.buildPartial();
+              }
+
               break;
             }
           default:
@@ -117,6 +133,586 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
             com.google.spanner.v1.CommitResponse.Builder.class);
   }
 
+  public interface CommitStatsOrBuilder
+      extends
+      // @@protoc_insertion_point(interface_extends:google.spanner.v1.CommitResponse.CommitStats)
+      com.google.protobuf.MessageOrBuilder {
+
+    /**
+     *
+     *
+     * <pre>
+     * The total number of mutations for the transaction. Knowing the
+     * `mutation_count` value can help you maximize the number of mutations
+     * in a transaction and minimize the number of API round trips. You can
+     * also monitor this value to prevent transactions from exceeding the system
+     * [limit](http://cloud.google.com/spanner/quotas#limits_for_creating_reading_updating_and_deleting_data).
+     * If the number of mutations exceeds the limit, the server returns
+     * [INVALID_ARGUMENT](http://cloud.google.com/spanner/docs/reference/rest/v1/Code#ENUM_VALUES.INVALID_ARGUMENT).
+     * </pre>
+     *
+     * <code>int64 mutation_count = 1;</code>
+     *
+     * @return The mutationCount.
+     */
+    long getMutationCount();
+  }
+  /**
+   *
+   *
+   * <pre>
+   * Additional statistics about a commit.
+   * </pre>
+   *
+   * Protobuf type {@code google.spanner.v1.CommitResponse.CommitStats}
+   */
+  public static final class CommitStats extends com.google.protobuf.GeneratedMessageV3
+      implements
+      // @@protoc_insertion_point(message_implements:google.spanner.v1.CommitResponse.CommitStats)
+      CommitStatsOrBuilder {
+    private static final long serialVersionUID = 0L;
+    // Use CommitStats.newBuilder() to construct.
+    private CommitStats(com.google.protobuf.GeneratedMessageV3.Builder<?> builder) {
+      super(builder);
+    }
+
+    private CommitStats() {}
+
+    @java.lang.Override
+    @SuppressWarnings({"unused"})
+    protected java.lang.Object newInstance(UnusedPrivateParameter unused) {
+      return new CommitStats();
+    }
+
+    @java.lang.Override
+    public final com.google.protobuf.UnknownFieldSet getUnknownFields() {
+      return this.unknownFields;
+    }
+
+    private CommitStats(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      this();
+      if (extensionRegistry == null) {
+        throw new java.lang.NullPointerException();
+      }
+      com.google.protobuf.UnknownFieldSet.Builder unknownFields =
+          com.google.protobuf.UnknownFieldSet.newBuilder();
+      try {
+        boolean done = false;
+        while (!done) {
+          int tag = input.readTag();
+          switch (tag) {
+            case 0:
+              done = true;
+              break;
+            case 8:
+              {
+                mutationCount_ = input.readInt64();
+                break;
+              }
+            default:
+              {
+                if (!parseUnknownField(input, unknownFields, extensionRegistry, tag)) {
+                  done = true;
+                }
+                break;
+              }
+          }
+        }
+      } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+        throw e.setUnfinishedMessage(this);
+      } catch (java.io.IOException e) {
+        throw new com.google.protobuf.InvalidProtocolBufferException(e).setUnfinishedMessage(this);
+      } finally {
+        this.unknownFields = unknownFields.build();
+        makeExtensionsImmutable();
+      }
+    }
+
+    public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
+      return com.google.spanner.v1.SpannerProto
+          .internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor;
+    }
+
+    @java.lang.Override
+    protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+        internalGetFieldAccessorTable() {
+      return com.google.spanner.v1.SpannerProto
+          .internal_static_google_spanner_v1_CommitResponse_CommitStats_fieldAccessorTable
+          .ensureFieldAccessorsInitialized(
+              com.google.spanner.v1.CommitResponse.CommitStats.class,
+              com.google.spanner.v1.CommitResponse.CommitStats.Builder.class);
+    }
+
+    public static final int MUTATION_COUNT_FIELD_NUMBER = 1;
+    private long mutationCount_;
+    /**
+     *
+     *
+     * <pre>
+     * The total number of mutations for the transaction. Knowing the
+     * `mutation_count` value can help you maximize the number of mutations
+     * in a transaction and minimize the number of API round trips. You can
+     * also monitor this value to prevent transactions from exceeding the system
+     * [limit](http://cloud.google.com/spanner/quotas#limits_for_creating_reading_updating_and_deleting_data).
+     * If the number of mutations exceeds the limit, the server returns
+     * [INVALID_ARGUMENT](http://cloud.google.com/spanner/docs/reference/rest/v1/Code#ENUM_VALUES.INVALID_ARGUMENT).
+     * </pre>
+     *
+     * <code>int64 mutation_count = 1;</code>
+     *
+     * @return The mutationCount.
+     */
+    @java.lang.Override
+    public long getMutationCount() {
+      return mutationCount_;
+    }
+
+    private byte memoizedIsInitialized = -1;
+
+    @java.lang.Override
+    public final boolean isInitialized() {
+      byte isInitialized = memoizedIsInitialized;
+      if (isInitialized == 1) return true;
+      if (isInitialized == 0) return false;
+
+      memoizedIsInitialized = 1;
+      return true;
+    }
+
+    @java.lang.Override
+    public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
+      if (mutationCount_ != 0L) {
+        output.writeInt64(1, mutationCount_);
+      }
+      unknownFields.writeTo(output);
+    }
+
+    @java.lang.Override
+    public int getSerializedSize() {
+      int size = memoizedSize;
+      if (size != -1) return size;
+
+      size = 0;
+      if (mutationCount_ != 0L) {
+        size += com.google.protobuf.CodedOutputStream.computeInt64Size(1, mutationCount_);
+      }
+      size += unknownFields.getSerializedSize();
+      memoizedSize = size;
+      return size;
+    }
+
+    @java.lang.Override
+    public boolean equals(final java.lang.Object obj) {
+      if (obj == this) {
+        return true;
+      }
+      if (!(obj instanceof com.google.spanner.v1.CommitResponse.CommitStats)) {
+        return super.equals(obj);
+      }
+      com.google.spanner.v1.CommitResponse.CommitStats other =
+          (com.google.spanner.v1.CommitResponse.CommitStats) obj;
+
+      if (getMutationCount() != other.getMutationCount()) return false;
+      if (!unknownFields.equals(other.unknownFields)) return false;
+      return true;
+    }
+
+    @java.lang.Override
+    public int hashCode() {
+      if (memoizedHashCode != 0) {
+        return memoizedHashCode;
+      }
+      int hash = 41;
+      hash = (19 * hash) + getDescriptor().hashCode();
+      hash = (37 * hash) + MUTATION_COUNT_FIELD_NUMBER;
+      hash = (53 * hash) + com.google.protobuf.Internal.hashLong(getMutationCount());
+      hash = (29 * hash) + unknownFields.hashCode();
+      memoizedHashCode = hash;
+      return hash;
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        java.nio.ByteBuffer data) throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        java.nio.ByteBuffer data, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        com.google.protobuf.ByteString data)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        com.google.protobuf.ByteString data,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(byte[] data)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        byte[] data, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws com.google.protobuf.InvalidProtocolBufferException {
+      return PARSER.parseFrom(data, extensionRegistry);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        java.io.InputStream input) throws java.io.IOException {
+      return com.google.protobuf.GeneratedMessageV3.parseWithIOException(PARSER, input);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        java.io.InputStream input, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return com.google.protobuf.GeneratedMessageV3.parseWithIOException(
+          PARSER, input, extensionRegistry);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseDelimitedFrom(
+        java.io.InputStream input) throws java.io.IOException {
+      return com.google.protobuf.GeneratedMessageV3.parseDelimitedWithIOException(PARSER, input);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseDelimitedFrom(
+        java.io.InputStream input, com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return com.google.protobuf.GeneratedMessageV3.parseDelimitedWithIOException(
+          PARSER, input, extensionRegistry);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        com.google.protobuf.CodedInputStream input) throws java.io.IOException {
+      return com.google.protobuf.GeneratedMessageV3.parseWithIOException(PARSER, input);
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats parseFrom(
+        com.google.protobuf.CodedInputStream input,
+        com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+        throws java.io.IOException {
+      return com.google.protobuf.GeneratedMessageV3.parseWithIOException(
+          PARSER, input, extensionRegistry);
+    }
+
+    @java.lang.Override
+    public Builder newBuilderForType() {
+      return newBuilder();
+    }
+
+    public static Builder newBuilder() {
+      return DEFAULT_INSTANCE.toBuilder();
+    }
+
+    public static Builder newBuilder(com.google.spanner.v1.CommitResponse.CommitStats prototype) {
+      return DEFAULT_INSTANCE.toBuilder().mergeFrom(prototype);
+    }
+
+    @java.lang.Override
+    public Builder toBuilder() {
+      return this == DEFAULT_INSTANCE ? new Builder() : new Builder().mergeFrom(this);
+    }
+
+    @java.lang.Override
+    protected Builder newBuilderForType(
+        com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+      Builder builder = new Builder(parent);
+      return builder;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * Additional statistics about a commit.
+     * </pre>
+     *
+     * Protobuf type {@code google.spanner.v1.CommitResponse.CommitStats}
+     */
+    public static final class Builder
+        extends com.google.protobuf.GeneratedMessageV3.Builder<Builder>
+        implements
+        // @@protoc_insertion_point(builder_implements:google.spanner.v1.CommitResponse.CommitStats)
+        com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder {
+      public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
+        return com.google.spanner.v1.SpannerProto
+            .internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor;
+      }
+
+      @java.lang.Override
+      protected com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+          internalGetFieldAccessorTable() {
+        return com.google.spanner.v1.SpannerProto
+            .internal_static_google_spanner_v1_CommitResponse_CommitStats_fieldAccessorTable
+            .ensureFieldAccessorsInitialized(
+                com.google.spanner.v1.CommitResponse.CommitStats.class,
+                com.google.spanner.v1.CommitResponse.CommitStats.Builder.class);
+      }
+
+      // Construct using com.google.spanner.v1.CommitResponse.CommitStats.newBuilder()
+      private Builder() {
+        maybeForceBuilderInitialization();
+      }
+
+      private Builder(com.google.protobuf.GeneratedMessageV3.BuilderParent parent) {
+        super(parent);
+        maybeForceBuilderInitialization();
+      }
+
+      private void maybeForceBuilderInitialization() {
+        if (com.google.protobuf.GeneratedMessageV3.alwaysUseFieldBuilders) {}
+      }
+
+      @java.lang.Override
+      public Builder clear() {
+        super.clear();
+        mutationCount_ = 0L;
+
+        return this;
+      }
+
+      @java.lang.Override
+      public com.google.protobuf.Descriptors.Descriptor getDescriptorForType() {
+        return com.google.spanner.v1.SpannerProto
+            .internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor;
+      }
+
+      @java.lang.Override
+      public com.google.spanner.v1.CommitResponse.CommitStats getDefaultInstanceForType() {
+        return com.google.spanner.v1.CommitResponse.CommitStats.getDefaultInstance();
+      }
+
+      @java.lang.Override
+      public com.google.spanner.v1.CommitResponse.CommitStats build() {
+        com.google.spanner.v1.CommitResponse.CommitStats result = buildPartial();
+        if (!result.isInitialized()) {
+          throw newUninitializedMessageException(result);
+        }
+        return result;
+      }
+
+      @java.lang.Override
+      public com.google.spanner.v1.CommitResponse.CommitStats buildPartial() {
+        com.google.spanner.v1.CommitResponse.CommitStats result =
+            new com.google.spanner.v1.CommitResponse.CommitStats(this);
+        result.mutationCount_ = mutationCount_;
+        onBuilt();
+        return result;
+      }
+
+      @java.lang.Override
+      public Builder clone() {
+        return super.clone();
+      }
+
+      @java.lang.Override
+      public Builder setField(
+          com.google.protobuf.Descriptors.FieldDescriptor field, java.lang.Object value) {
+        return super.setField(field, value);
+      }
+
+      @java.lang.Override
+      public Builder clearField(com.google.protobuf.Descriptors.FieldDescriptor field) {
+        return super.clearField(field);
+      }
+
+      @java.lang.Override
+      public Builder clearOneof(com.google.protobuf.Descriptors.OneofDescriptor oneof) {
+        return super.clearOneof(oneof);
+      }
+
+      @java.lang.Override
+      public Builder setRepeatedField(
+          com.google.protobuf.Descriptors.FieldDescriptor field,
+          int index,
+          java.lang.Object value) {
+        return super.setRepeatedField(field, index, value);
+      }
+
+      @java.lang.Override
+      public Builder addRepeatedField(
+          com.google.protobuf.Descriptors.FieldDescriptor field, java.lang.Object value) {
+        return super.addRepeatedField(field, value);
+      }
+
+      @java.lang.Override
+      public Builder mergeFrom(com.google.protobuf.Message other) {
+        if (other instanceof com.google.spanner.v1.CommitResponse.CommitStats) {
+          return mergeFrom((com.google.spanner.v1.CommitResponse.CommitStats) other);
+        } else {
+          super.mergeFrom(other);
+          return this;
+        }
+      }
+
+      public Builder mergeFrom(com.google.spanner.v1.CommitResponse.CommitStats other) {
+        if (other == com.google.spanner.v1.CommitResponse.CommitStats.getDefaultInstance())
+          return this;
+        if (other.getMutationCount() != 0L) {
+          setMutationCount(other.getMutationCount());
+        }
+        this.mergeUnknownFields(other.unknownFields);
+        onChanged();
+        return this;
+      }
+
+      @java.lang.Override
+      public final boolean isInitialized() {
+        return true;
+      }
+
+      @java.lang.Override
+      public Builder mergeFrom(
+          com.google.protobuf.CodedInputStream input,
+          com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+          throws java.io.IOException {
+        com.google.spanner.v1.CommitResponse.CommitStats parsedMessage = null;
+        try {
+          parsedMessage = PARSER.parsePartialFrom(input, extensionRegistry);
+        } catch (com.google.protobuf.InvalidProtocolBufferException e) {
+          parsedMessage =
+              (com.google.spanner.v1.CommitResponse.CommitStats) e.getUnfinishedMessage();
+          throw e.unwrapIOException();
+        } finally {
+          if (parsedMessage != null) {
+            mergeFrom(parsedMessage);
+          }
+        }
+        return this;
+      }
+
+      private long mutationCount_;
+      /**
+       *
+       *
+       * <pre>
+       * The total number of mutations for the transaction. Knowing the
+       * `mutation_count` value can help you maximize the number of mutations
+       * in a transaction and minimize the number of API round trips. You can
+       * also monitor this value to prevent transactions from exceeding the system
+       * [limit](http://cloud.google.com/spanner/quotas#limits_for_creating_reading_updating_and_deleting_data).
+       * If the number of mutations exceeds the limit, the server returns
+       * [INVALID_ARGUMENT](http://cloud.google.com/spanner/docs/reference/rest/v1/Code#ENUM_VALUES.INVALID_ARGUMENT).
+       * </pre>
+       *
+       * <code>int64 mutation_count = 1;</code>
+       *
+       * @return The mutationCount.
+       */
+      @java.lang.Override
+      public long getMutationCount() {
+        return mutationCount_;
+      }
+      /**
+       *
+       *
+       * <pre>
+       * The total number of mutations for the transaction. Knowing the
+       * `mutation_count` value can help you maximize the number of mutations
+       * in a transaction and minimize the number of API round trips. You can
+       * also monitor this value to prevent transactions from exceeding the system
+       * [limit](http://cloud.google.com/spanner/quotas#limits_for_creating_reading_updating_and_deleting_data).
+       * If the number of mutations exceeds the limit, the server returns
+       * [INVALID_ARGUMENT](http://cloud.google.com/spanner/docs/reference/rest/v1/Code#ENUM_VALUES.INVALID_ARGUMENT).
+       * </pre>
+       *
+       * <code>int64 mutation_count = 1;</code>
+       *
+       * @param value The mutationCount to set.
+       * @return This builder for chaining.
+       */
+      public Builder setMutationCount(long value) {
+
+        mutationCount_ = value;
+        onChanged();
+        return this;
+      }
+      /**
+       *
+       *
+       * <pre>
+       * The total number of mutations for the transaction. Knowing the
+       * `mutation_count` value can help you maximize the number of mutations
+       * in a transaction and minimize the number of API round trips. You can
+       * also monitor this value to prevent transactions from exceeding the system
+       * [limit](http://cloud.google.com/spanner/quotas#limits_for_creating_reading_updating_and_deleting_data).
+       * If the number of mutations exceeds the limit, the server returns
+       * [INVALID_ARGUMENT](http://cloud.google.com/spanner/docs/reference/rest/v1/Code#ENUM_VALUES.INVALID_ARGUMENT).
+       * </pre>
+       *
+       * <code>int64 mutation_count = 1;</code>
+       *
+       * @return This builder for chaining.
+       */
+      public Builder clearMutationCount() {
+
+        mutationCount_ = 0L;
+        onChanged();
+        return this;
+      }
+
+      @java.lang.Override
+      public final Builder setUnknownFields(
+          final com.google.protobuf.UnknownFieldSet unknownFields) {
+        return super.setUnknownFields(unknownFields);
+      }
+
+      @java.lang.Override
+      public final Builder mergeUnknownFields(
+          final com.google.protobuf.UnknownFieldSet unknownFields) {
+        return super.mergeUnknownFields(unknownFields);
+      }
+
+      // @@protoc_insertion_point(builder_scope:google.spanner.v1.CommitResponse.CommitStats)
+    }
+
+    // @@protoc_insertion_point(class_scope:google.spanner.v1.CommitResponse.CommitStats)
+    private static final com.google.spanner.v1.CommitResponse.CommitStats DEFAULT_INSTANCE;
+
+    static {
+      DEFAULT_INSTANCE = new com.google.spanner.v1.CommitResponse.CommitStats();
+    }
+
+    public static com.google.spanner.v1.CommitResponse.CommitStats getDefaultInstance() {
+      return DEFAULT_INSTANCE;
+    }
+
+    private static final com.google.protobuf.Parser<CommitStats> PARSER =
+        new com.google.protobuf.AbstractParser<CommitStats>() {
+          @java.lang.Override
+          public CommitStats parsePartialFrom(
+              com.google.protobuf.CodedInputStream input,
+              com.google.protobuf.ExtensionRegistryLite extensionRegistry)
+              throws com.google.protobuf.InvalidProtocolBufferException {
+            return new CommitStats(input, extensionRegistry);
+          }
+        };
+
+    public static com.google.protobuf.Parser<CommitStats> parser() {
+      return PARSER;
+    }
+
+    @java.lang.Override
+    public com.google.protobuf.Parser<CommitStats> getParserForType() {
+      return PARSER;
+    }
+
+    @java.lang.Override
+    public com.google.spanner.v1.CommitResponse.CommitStats getDefaultInstanceForType() {
+      return DEFAULT_INSTANCE;
+    }
+  }
+
   public static final int COMMIT_TIMESTAMP_FIELD_NUMBER = 1;
   private com.google.protobuf.Timestamp commitTimestamp_;
   /**
@@ -165,6 +761,60 @@ public com.google.protobuf.TimestampOrBuilder getCommitTimestampOrBuilder() {
     return getCommitTimestamp();
   }
 
+  public static final int COMMIT_STATS_FIELD_NUMBER = 2;
+  private com.google.spanner.v1.CommitResponse.CommitStats commitStats_;
+  /**
+   *
+   *
+   * <pre>
+   * The statistics about this Commit. Not returned by default.
+   * For more information, see
+   * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+   * </pre>
+   *
+   * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+   *
+   * @return Whether the commitStats field is set.
+   */
+  @java.lang.Override
+  public boolean hasCommitStats() {
+    return commitStats_ != null;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * The statistics about this Commit. Not returned by default.
+   * For more information, see
+   * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+   * </pre>
+   *
+   * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+   *
+   * @return The commitStats.
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.CommitResponse.CommitStats getCommitStats() {
+    return commitStats_ == null
+        ? com.google.spanner.v1.CommitResponse.CommitStats.getDefaultInstance()
+        : commitStats_;
+  }
+  /**
+   *
+   *
+   * <pre>
+   * The statistics about this Commit. Not returned by default.
+   * For more information, see
+   * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+   * </pre>
+   *
+   * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+   */
+  @java.lang.Override
+  public com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder getCommitStatsOrBuilder() {
+    return getCommitStats();
+  }
+
   private byte memoizedIsInitialized = -1;
 
   @java.lang.Override
@@ -182,6 +832,9 @@ public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io
     if (commitTimestamp_ != null) {
       output.writeMessage(1, getCommitTimestamp());
     }
+    if (commitStats_ != null) {
+      output.writeMessage(2, getCommitStats());
+    }
     unknownFields.writeTo(output);
   }
 
@@ -194,6 +847,9 @@ public int getSerializedSize() {
     if (commitTimestamp_ != null) {
       size += com.google.protobuf.CodedOutputStream.computeMessageSize(1, getCommitTimestamp());
     }
+    if (commitStats_ != null) {
+      size += com.google.protobuf.CodedOutputStream.computeMessageSize(2, getCommitStats());
+    }
     size += unknownFields.getSerializedSize();
     memoizedSize = size;
     return size;
@@ -213,6 +869,10 @@ public boolean equals(final java.lang.Object obj) {
     if (hasCommitTimestamp()) {
       if (!getCommitTimestamp().equals(other.getCommitTimestamp())) return false;
     }
+    if (hasCommitStats() != other.hasCommitStats()) return false;
+    if (hasCommitStats()) {
+      if (!getCommitStats().equals(other.getCommitStats())) return false;
+    }
     if (!unknownFields.equals(other.unknownFields)) return false;
     return true;
   }
@@ -228,6 +888,10 @@ public int hashCode() {
       hash = (37 * hash) + COMMIT_TIMESTAMP_FIELD_NUMBER;
       hash = (53 * hash) + getCommitTimestamp().hashCode();
     }
+    if (hasCommitStats()) {
+      hash = (37 * hash) + COMMIT_STATS_FIELD_NUMBER;
+      hash = (53 * hash) + getCommitStats().hashCode();
+    }
     hash = (29 * hash) + unknownFields.hashCode();
     memoizedHashCode = hash;
     return hash;
@@ -378,6 +1042,12 @@ public Builder clear() {
         commitTimestamp_ = null;
         commitTimestampBuilder_ = null;
       }
+      if (commitStatsBuilder_ == null) {
+        commitStats_ = null;
+      } else {
+        commitStats_ = null;
+        commitStatsBuilder_ = null;
+      }
       return this;
     }
 
@@ -409,6 +1079,11 @@ public com.google.spanner.v1.CommitResponse buildPartial() {
       } else {
         result.commitTimestamp_ = commitTimestampBuilder_.build();
       }
+      if (commitStatsBuilder_ == null) {
+        result.commitStats_ = commitStats_;
+      } else {
+        result.commitStats_ = commitStatsBuilder_.build();
+      }
       onBuilt();
       return result;
     }
@@ -461,6 +1136,9 @@ public Builder mergeFrom(com.google.spanner.v1.CommitResponse other) {
       if (other.hasCommitTimestamp()) {
         mergeCommitTimestamp(other.getCommitTimestamp());
       }
+      if (other.hasCommitStats()) {
+        mergeCommitStats(other.getCommitStats());
+      }
       this.mergeUnknownFields(other.unknownFields);
       onChanged();
       return this;
@@ -675,6 +1353,210 @@ public com.google.protobuf.TimestampOrBuilder getCommitTimestampOrBuilder() {
       return commitTimestampBuilder_;
     }
 
+    private com.google.spanner.v1.CommitResponse.CommitStats commitStats_;
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.CommitResponse.CommitStats,
+            com.google.spanner.v1.CommitResponse.CommitStats.Builder,
+            com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder>
+        commitStatsBuilder_;
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     *
+     * @return Whether the commitStats field is set.
+     */
+    public boolean hasCommitStats() {
+      return commitStatsBuilder_ != null || commitStats_ != null;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     *
+     * @return The commitStats.
+     */
+    public com.google.spanner.v1.CommitResponse.CommitStats getCommitStats() {
+      if (commitStatsBuilder_ == null) {
+        return commitStats_ == null
+            ? com.google.spanner.v1.CommitResponse.CommitStats.getDefaultInstance()
+            : commitStats_;
+      } else {
+        return commitStatsBuilder_.getMessage();
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    public Builder setCommitStats(com.google.spanner.v1.CommitResponse.CommitStats value) {
+      if (commitStatsBuilder_ == null) {
+        if (value == null) {
+          throw new NullPointerException();
+        }
+        commitStats_ = value;
+        onChanged();
+      } else {
+        commitStatsBuilder_.setMessage(value);
+      }
+
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    public Builder setCommitStats(
+        com.google.spanner.v1.CommitResponse.CommitStats.Builder builderForValue) {
+      if (commitStatsBuilder_ == null) {
+        commitStats_ = builderForValue.build();
+        onChanged();
+      } else {
+        commitStatsBuilder_.setMessage(builderForValue.build());
+      }
+
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    public Builder mergeCommitStats(com.google.spanner.v1.CommitResponse.CommitStats value) {
+      if (commitStatsBuilder_ == null) {
+        if (commitStats_ != null) {
+          commitStats_ =
+              com.google.spanner.v1.CommitResponse.CommitStats.newBuilder(commitStats_)
+                  .mergeFrom(value)
+                  .buildPartial();
+        } else {
+          commitStats_ = value;
+        }
+        onChanged();
+      } else {
+        commitStatsBuilder_.mergeFrom(value);
+      }
+
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    public Builder clearCommitStats() {
+      if (commitStatsBuilder_ == null) {
+        commitStats_ = null;
+        onChanged();
+      } else {
+        commitStats_ = null;
+        commitStatsBuilder_ = null;
+      }
+
+      return this;
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    public com.google.spanner.v1.CommitResponse.CommitStats.Builder getCommitStatsBuilder() {
+
+      onChanged();
+      return getCommitStatsFieldBuilder().getBuilder();
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    public com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder getCommitStatsOrBuilder() {
+      if (commitStatsBuilder_ != null) {
+        return commitStatsBuilder_.getMessageOrBuilder();
+      } else {
+        return commitStats_ == null
+            ? com.google.spanner.v1.CommitResponse.CommitStats.getDefaultInstance()
+            : commitStats_;
+      }
+    }
+    /**
+     *
+     *
+     * <pre>
+     * The statistics about this Commit. Not returned by default.
+     * For more information, see
+     * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+     * </pre>
+     *
+     * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+     */
+    private com.google.protobuf.SingleFieldBuilderV3<
+            com.google.spanner.v1.CommitResponse.CommitStats,
+            com.google.spanner.v1.CommitResponse.CommitStats.Builder,
+            com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder>
+        getCommitStatsFieldBuilder() {
+      if (commitStatsBuilder_ == null) {
+        commitStatsBuilder_ =
+            new com.google.protobuf.SingleFieldBuilderV3<
+                com.google.spanner.v1.CommitResponse.CommitStats,
+                com.google.spanner.v1.CommitResponse.CommitStats.Builder,
+                com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder>(
+                getCommitStats(), getParentForChildren(), isClean());
+        commitStats_ = null;
+      }
+      return commitStatsBuilder_;
+    }
+
     @java.lang.Override
     public final Builder setUnknownFields(final com.google.protobuf.UnknownFieldSet unknownFields) {
       return super.setUnknownFields(unknownFields);
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java
index 90c6c6e672..9ff076ff84 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/CommitResponseOrBuilder.java
@@ -57,4 +57,45 @@ public interface CommitResponseOrBuilder
    * <code>.google.protobuf.Timestamp commit_timestamp = 1;</code>
    */
   com.google.protobuf.TimestampOrBuilder getCommitTimestampOrBuilder();
+
+  /**
+   *
+   *
+   * <pre>
+   * The statistics about this Commit. Not returned by default.
+   * For more information, see
+   * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+   * </pre>
+   *
+   * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+   *
+   * @return Whether the commitStats field is set.
+   */
+  boolean hasCommitStats();
+  /**
+   *
+   *
+   * <pre>
+   * The statistics about this Commit. Not returned by default.
+   * For more information, see
+   * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+   * </pre>
+   *
+   * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+   *
+   * @return The commitStats.
+   */
+  com.google.spanner.v1.CommitResponse.CommitStats getCommitStats();
+  /**
+   *
+   *
+   * <pre>
+   * The statistics about this Commit. Not returned by default.
+   * For more information, see
+   * [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+   * </pre>
+   *
+   * <code>.google.spanner.v1.CommitResponse.CommitStats commit_stats = 2;</code>
+   */
+  com.google.spanner.v1.CommitResponse.CommitStatsOrBuilder getCommitStatsOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequest.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequest.java
index 1e757805fd..79a7ad822b 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequest.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequest.java
@@ -402,6 +402,9 @@ public interface QueryOptionsOrBuilder
      * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
      * with an invalid optimizer version will fail with a syntax error
      * (`INVALID_ARGUMENT`) status.
+     * See
+     * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+     * for more information on managing the query optimizer.
      * The `optimizer_version` statement hint has precedence over this setting.
      * </pre>
      *
@@ -426,6 +429,9 @@ public interface QueryOptionsOrBuilder
      * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
      * with an invalid optimizer version will fail with a syntax error
      * (`INVALID_ARGUMENT`) status.
+     * See
+     * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+     * for more information on managing the query optimizer.
      * The `optimizer_version` statement hint has precedence over this setting.
      * </pre>
      *
@@ -546,6 +552,9 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
      * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
      * with an invalid optimizer version will fail with a syntax error
      * (`INVALID_ARGUMENT`) status.
+     * See
+     * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+     * for more information on managing the query optimizer.
      * The `optimizer_version` statement hint has precedence over this setting.
      * </pre>
      *
@@ -581,6 +590,9 @@ public java.lang.String getOptimizerVersion() {
      * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
      * with an invalid optimizer version will fail with a syntax error
      * (`INVALID_ARGUMENT`) status.
+     * See
+     * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+     * for more information on managing the query optimizer.
      * The `optimizer_version` statement hint has precedence over this setting.
      * </pre>
      *
@@ -941,6 +953,9 @@ public Builder mergeFrom(
        * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
        * with an invalid optimizer version will fail with a syntax error
        * (`INVALID_ARGUMENT`) status.
+       * See
+       * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+       * for more information on managing the query optimizer.
        * The `optimizer_version` statement hint has precedence over this setting.
        * </pre>
        *
@@ -975,6 +990,9 @@ public java.lang.String getOptimizerVersion() {
        * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
        * with an invalid optimizer version will fail with a syntax error
        * (`INVALID_ARGUMENT`) status.
+       * See
+       * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+       * for more information on managing the query optimizer.
        * The `optimizer_version` statement hint has precedence over this setting.
        * </pre>
        *
@@ -1009,6 +1027,9 @@ public com.google.protobuf.ByteString getOptimizerVersionBytes() {
        * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
        * with an invalid optimizer version will fail with a syntax error
        * (`INVALID_ARGUMENT`) status.
+       * See
+       * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+       * for more information on managing the query optimizer.
        * The `optimizer_version` statement hint has precedence over this setting.
        * </pre>
        *
@@ -1042,6 +1063,9 @@ public Builder setOptimizerVersion(java.lang.String value) {
        * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
        * with an invalid optimizer version will fail with a syntax error
        * (`INVALID_ARGUMENT`) status.
+       * See
+       * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+       * for more information on managing the query optimizer.
        * The `optimizer_version` statement hint has precedence over this setting.
        * </pre>
        *
@@ -1071,6 +1095,9 @@ public Builder clearOptimizerVersion() {
        * SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
        * with an invalid optimizer version will fail with a syntax error
        * (`INVALID_ARGUMENT`) status.
+       * See
+       * https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+       * for more information on managing the query optimizer.
        * The `optimizer_version` statement hint has precedence over this setting.
        * </pre>
        *
@@ -1318,8 +1345,9 @@ public com.google.protobuf.ByteString getSqlBytes() {
    * <pre>
    * Parameter names and values that bind to placeholders in the SQL string.
    * A parameter placeholder consists of the `&#64;` character followed by the
-   * parameter name (for example, `&#64;firstName`). Parameter names can contain
-   * letters, numbers, and underscores.
+   * parameter name (for example, `&#64;firstName`). Parameter names must conform
+   * to the naming requirements of identifiers as specified at
+   * https://cloud.google.com/spanner/docs/lexical#identifiers.
    * Parameters can appear anywhere that a literal value is expected.  The same
    * parameter name can be used more than once, for example:
    * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -1340,8 +1368,9 @@ public boolean hasParams() {
    * <pre>
    * Parameter names and values that bind to placeholders in the SQL string.
    * A parameter placeholder consists of the `&#64;` character followed by the
-   * parameter name (for example, `&#64;firstName`). Parameter names can contain
-   * letters, numbers, and underscores.
+   * parameter name (for example, `&#64;firstName`). Parameter names must conform
+   * to the naming requirements of identifiers as specified at
+   * https://cloud.google.com/spanner/docs/lexical#identifiers.
    * Parameters can appear anywhere that a literal value is expected.  The same
    * parameter name can be used more than once, for example:
    * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -1362,8 +1391,9 @@ public com.google.protobuf.Struct getParams() {
    * <pre>
    * Parameter names and values that bind to placeholders in the SQL string.
    * A parameter placeholder consists of the `&#64;` character followed by the
-   * parameter name (for example, `&#64;firstName`). Parameter names can contain
-   * letters, numbers, and underscores.
+   * parameter name (for example, `&#64;firstName`). Parameter names must conform
+   * to the naming requirements of identifiers as specified at
+   * https://cloud.google.com/spanner/docs/lexical#identifiers.
    * Parameters can appear anywhere that a literal value is expected.  The same
    * parameter name can be used more than once, for example:
    * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2656,8 +2686,9 @@ public Builder setSqlBytes(com.google.protobuf.ByteString value) {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2677,8 +2708,9 @@ public boolean hasParams() {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2702,8 +2734,9 @@ public com.google.protobuf.Struct getParams() {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2731,8 +2764,9 @@ public Builder setParams(com.google.protobuf.Struct value) {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2757,8 +2791,9 @@ public Builder setParams(com.google.protobuf.Struct.Builder builderForValue) {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2787,8 +2822,9 @@ public Builder mergeParams(com.google.protobuf.Struct value) {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2814,8 +2850,9 @@ public Builder clearParams() {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2835,8 +2872,9 @@ public com.google.protobuf.Struct.Builder getParamsBuilder() {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -2858,8 +2896,9 @@ public com.google.protobuf.StructOrBuilder getParamsOrBuilder() {
      * <pre>
      * Parameter names and values that bind to placeholders in the SQL string.
      * A parameter placeholder consists of the `&#64;` character followed by the
-     * parameter name (for example, `&#64;firstName`). Parameter names can contain
-     * letters, numbers, and underscores.
+     * parameter name (for example, `&#64;firstName`). Parameter names must conform
+     * to the naming requirements of identifiers as specified at
+     * https://cloud.google.com/spanner/docs/lexical#identifiers.
      * Parameters can appear anywhere that a literal value is expected.  The same
      * parameter name can be used more than once, for example:
      * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequestOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequestOrBuilder.java
index 7971beeb49..d6af9b0ba6 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequestOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/ExecuteSqlRequestOrBuilder.java
@@ -136,8 +136,9 @@ public interface ExecuteSqlRequestOrBuilder
    * <pre>
    * Parameter names and values that bind to placeholders in the SQL string.
    * A parameter placeholder consists of the `&#64;` character followed by the
-   * parameter name (for example, `&#64;firstName`). Parameter names can contain
-   * letters, numbers, and underscores.
+   * parameter name (for example, `&#64;firstName`). Parameter names must conform
+   * to the naming requirements of identifiers as specified at
+   * https://cloud.google.com/spanner/docs/lexical#identifiers.
    * Parameters can appear anywhere that a literal value is expected.  The same
    * parameter name can be used more than once, for example:
    * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -155,8 +156,9 @@ public interface ExecuteSqlRequestOrBuilder
    * <pre>
    * Parameter names and values that bind to placeholders in the SQL string.
    * A parameter placeholder consists of the `&#64;` character followed by the
-   * parameter name (for example, `&#64;firstName`). Parameter names can contain
-   * letters, numbers, and underscores.
+   * parameter name (for example, `&#64;firstName`). Parameter names must conform
+   * to the naming requirements of identifiers as specified at
+   * https://cloud.google.com/spanner/docs/lexical#identifiers.
    * Parameters can appear anywhere that a literal value is expected.  The same
    * parameter name can be used more than once, for example:
    * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
@@ -174,8 +176,9 @@ public interface ExecuteSqlRequestOrBuilder
    * <pre>
    * Parameter names and values that bind to placeholders in the SQL string.
    * A parameter placeholder consists of the `&#64;` character followed by the
-   * parameter name (for example, `&#64;firstName`). Parameter names can contain
-   * letters, numbers, and underscores.
+   * parameter name (for example, `&#64;firstName`). Parameter names must conform
+   * to the naming requirements of identifiers as specified at
+   * https://cloud.google.com/spanner/docs/lexical#identifiers.
    * Parameters can appear anywhere that a literal value is expected.  The same
    * parameter name can be used more than once, for example:
    * `"WHERE id &gt; &#64;msg_id AND id &lt; &#64;msg_id + 100"`
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Session.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Session.java
index 9fe4f10c7c..1b058eb621 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Session.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/Session.java
@@ -170,11 +170,10 @@ protected com.google.protobuf.MapField internalGetMapField(int number) {
    *
    *
    * <pre>
-   * The name of the session. This is always system-assigned; values provided
-   * when creating a session are ignored.
+   * Output only. The name of the session. This is always system-assigned.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
    *
    * @return The name.
    */
@@ -194,11 +193,10 @@ public java.lang.String getName() {
    *
    *
    * <pre>
-   * The name of the session. This is always system-assigned; values provided
-   * when creating a session are ignored.
+   * Output only. The name of the session. This is always system-assigned.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
    *
    * @return The bytes for name.
    */
@@ -346,7 +344,8 @@ public java.lang.String getLabelsOrThrow(java.lang.String key) {
    * Output only. The timestamp when the session is created.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp create_time = 3;</code>
+   * <code>.google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return Whether the createTime field is set.
    */
@@ -361,7 +360,8 @@ public boolean hasCreateTime() {
    * Output only. The timestamp when the session is created.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp create_time = 3;</code>
+   * <code>.google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return The createTime.
    */
@@ -376,7 +376,8 @@ public com.google.protobuf.Timestamp getCreateTime() {
    * Output only. The timestamp when the session is created.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp create_time = 3;</code>
+   * <code>.google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    */
   @java.lang.Override
   public com.google.protobuf.TimestampOrBuilder getCreateTimeOrBuilder() {
@@ -393,7 +394,9 @@ public com.google.protobuf.TimestampOrBuilder getCreateTimeOrBuilder() {
    * typically earlier than the actual last use time.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+   * <code>
+   * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return Whether the approximateLastUseTime field is set.
    */
@@ -409,7 +412,9 @@ public boolean hasApproximateLastUseTime() {
    * typically earlier than the actual last use time.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+   * <code>
+   * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return The approximateLastUseTime.
    */
@@ -427,7 +432,9 @@ public com.google.protobuf.Timestamp getApproximateLastUseTime() {
    * typically earlier than the actual last use time.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+   * <code>
+   * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    */
   @java.lang.Override
   public com.google.protobuf.TimestampOrBuilder getApproximateLastUseTimeOrBuilder() {
@@ -852,11 +859,10 @@ public Builder mergeFrom(
      *
      *
      * <pre>
-     * The name of the session. This is always system-assigned; values provided
-     * when creating a session are ignored.
+     * Output only. The name of the session. This is always system-assigned.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      *
      * @return The name.
      */
@@ -875,11 +881,10 @@ public java.lang.String getName() {
      *
      *
      * <pre>
-     * The name of the session. This is always system-assigned; values provided
-     * when creating a session are ignored.
+     * Output only. The name of the session. This is always system-assigned.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      *
      * @return The bytes for name.
      */
@@ -898,11 +903,10 @@ public com.google.protobuf.ByteString getNameBytes() {
      *
      *
      * <pre>
-     * The name of the session. This is always system-assigned; values provided
-     * when creating a session are ignored.
+     * Output only. The name of the session. This is always system-assigned.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      *
      * @param value The name to set.
      * @return This builder for chaining.
@@ -920,11 +924,10 @@ public Builder setName(java.lang.String value) {
      *
      *
      * <pre>
-     * The name of the session. This is always system-assigned; values provided
-     * when creating a session are ignored.
+     * Output only. The name of the session. This is always system-assigned.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      *
      * @return This builder for chaining.
      */
@@ -938,11 +941,10 @@ public Builder clearName() {
      *
      *
      * <pre>
-     * The name of the session. This is always system-assigned; values provided
-     * when creating a session are ignored.
+     * Output only. The name of the session. This is always system-assigned.
      * </pre>
      *
-     * <code>string name = 1;</code>
+     * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
      *
      * @param value The bytes for name to set.
      * @return This builder for chaining.
@@ -1170,7 +1172,9 @@ public Builder putAllLabels(java.util.Map<java.lang.String, java.lang.String> va
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      *
      * @return Whether the createTime field is set.
      */
@@ -1184,7 +1188,9 @@ public boolean hasCreateTime() {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      *
      * @return The createTime.
      */
@@ -1204,7 +1210,9 @@ public com.google.protobuf.Timestamp getCreateTime() {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder setCreateTime(com.google.protobuf.Timestamp value) {
       if (createTimeBuilder_ == null) {
@@ -1226,7 +1234,9 @@ public Builder setCreateTime(com.google.protobuf.Timestamp value) {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder setCreateTime(com.google.protobuf.Timestamp.Builder builderForValue) {
       if (createTimeBuilder_ == null) {
@@ -1245,7 +1255,9 @@ public Builder setCreateTime(com.google.protobuf.Timestamp.Builder builderForVal
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder mergeCreateTime(com.google.protobuf.Timestamp value) {
       if (createTimeBuilder_ == null) {
@@ -1269,7 +1281,9 @@ public Builder mergeCreateTime(com.google.protobuf.Timestamp value) {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder clearCreateTime() {
       if (createTimeBuilder_ == null) {
@@ -1289,7 +1303,9 @@ public Builder clearCreateTime() {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public com.google.protobuf.Timestamp.Builder getCreateTimeBuilder() {
 
@@ -1303,7 +1319,9 @@ public com.google.protobuf.Timestamp.Builder getCreateTimeBuilder() {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public com.google.protobuf.TimestampOrBuilder getCreateTimeOrBuilder() {
       if (createTimeBuilder_ != null) {
@@ -1321,7 +1339,9 @@ public com.google.protobuf.TimestampOrBuilder getCreateTimeOrBuilder() {
      * Output only. The timestamp when the session is created.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp create_time = 3;</code>
+     * <code>
+     * .google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.protobuf.Timestamp,
@@ -1354,7 +1374,9 @@ public com.google.protobuf.TimestampOrBuilder getCreateTimeOrBuilder() {
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      *
      * @return Whether the approximateLastUseTime field is set.
      */
@@ -1369,7 +1391,9 @@ public boolean hasApproximateLastUseTime() {
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      *
      * @return The approximateLastUseTime.
      */
@@ -1390,7 +1414,9 @@ public com.google.protobuf.Timestamp getApproximateLastUseTime() {
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder setApproximateLastUseTime(com.google.protobuf.Timestamp value) {
       if (approximateLastUseTimeBuilder_ == null) {
@@ -1413,7 +1439,9 @@ public Builder setApproximateLastUseTime(com.google.protobuf.Timestamp value) {
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder setApproximateLastUseTime(
         com.google.protobuf.Timestamp.Builder builderForValue) {
@@ -1434,7 +1462,9 @@ public Builder setApproximateLastUseTime(
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder mergeApproximateLastUseTime(com.google.protobuf.Timestamp value) {
       if (approximateLastUseTimeBuilder_ == null) {
@@ -1461,7 +1491,9 @@ public Builder mergeApproximateLastUseTime(com.google.protobuf.Timestamp value)
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public Builder clearApproximateLastUseTime() {
       if (approximateLastUseTimeBuilder_ == null) {
@@ -1482,7 +1514,9 @@ public Builder clearApproximateLastUseTime() {
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public com.google.protobuf.Timestamp.Builder getApproximateLastUseTimeBuilder() {
 
@@ -1497,7 +1531,9 @@ public com.google.protobuf.Timestamp.Builder getApproximateLastUseTimeBuilder()
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     public com.google.protobuf.TimestampOrBuilder getApproximateLastUseTimeOrBuilder() {
       if (approximateLastUseTimeBuilder_ != null) {
@@ -1516,7 +1552,9 @@ public com.google.protobuf.TimestampOrBuilder getApproximateLastUseTimeOrBuilder
      * typically earlier than the actual last use time.
      * </pre>
      *
-     * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+     * <code>
+     * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+     * </code>
      */
     private com.google.protobuf.SingleFieldBuilderV3<
             com.google.protobuf.Timestamp,
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SessionOrBuilder.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SessionOrBuilder.java
index 6b7fc5b822..556832d009 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SessionOrBuilder.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SessionOrBuilder.java
@@ -27,11 +27,10 @@ public interface SessionOrBuilder
    *
    *
    * <pre>
-   * The name of the session. This is always system-assigned; values provided
-   * when creating a session are ignored.
+   * Output only. The name of the session. This is always system-assigned.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
    *
    * @return The name.
    */
@@ -40,11 +39,10 @@ public interface SessionOrBuilder
    *
    *
    * <pre>
-   * The name of the session. This is always system-assigned; values provided
-   * when creating a session are ignored.
+   * Output only. The name of the session. This is always system-assigned.
    * </pre>
    *
-   * <code>string name = 1;</code>
+   * <code>string name = 1 [(.google.api.field_behavior) = OUTPUT_ONLY];</code>
    *
    * @return The bytes for name.
    */
@@ -141,7 +139,8 @@ public interface SessionOrBuilder
    * Output only. The timestamp when the session is created.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp create_time = 3;</code>
+   * <code>.google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return Whether the createTime field is set.
    */
@@ -153,7 +152,8 @@ public interface SessionOrBuilder
    * Output only. The timestamp when the session is created.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp create_time = 3;</code>
+   * <code>.google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return The createTime.
    */
@@ -165,7 +165,8 @@ public interface SessionOrBuilder
    * Output only. The timestamp when the session is created.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp create_time = 3;</code>
+   * <code>.google.protobuf.Timestamp create_time = 3 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    */
   com.google.protobuf.TimestampOrBuilder getCreateTimeOrBuilder();
 
@@ -177,7 +178,9 @@ public interface SessionOrBuilder
    * typically earlier than the actual last use time.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+   * <code>
+   * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return Whether the approximateLastUseTime field is set.
    */
@@ -190,7 +193,9 @@ public interface SessionOrBuilder
    * typically earlier than the actual last use time.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+   * <code>
+   * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    *
    * @return The approximateLastUseTime.
    */
@@ -203,7 +208,9 @@ public interface SessionOrBuilder
    * typically earlier than the actual last use time.
    * </pre>
    *
-   * <code>.google.protobuf.Timestamp approximate_last_use_time = 4;</code>
+   * <code>
+   * .google.protobuf.Timestamp approximate_last_use_time = 4 [(.google.api.field_behavior) = OUTPUT_ONLY];
+   * </code>
    */
   com.google.protobuf.TimestampOrBuilder getApproximateLastUseTimeOrBuilder();
 }
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java
index 0932ab5d52..8458063ada 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/SpannerProto.java
@@ -131,6 +131,10 @@ public static void registerAllExtensions(com.google.protobuf.ExtensionRegistry r
       internal_static_google_spanner_v1_CommitResponse_descriptor;
   static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
       internal_static_google_spanner_v1_CommitResponse_fieldAccessorTable;
+  static final com.google.protobuf.Descriptors.Descriptor
+      internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor;
+  static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
+      internal_static_google_spanner_v1_CommitResponse_CommitStats_fieldAccessorTable;
   static final com.google.protobuf.Descriptors.Descriptor
       internal_static_google_spanner_v1_RollbackRequest_descriptor;
   static final com.google.protobuf.GeneratedMessageV3.FieldAccessorTable
@@ -148,198 +152,202 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
           + "e.spanner.v1\032\034google/api/annotations.pro"
           + "to\032\027google/api/client.proto\032\037google/api/"
           + "field_behavior.proto\032\031google/api/resourc"
-          + "e.proto\032\033google/protobuf/empty.proto\032\034go"
-          + "ogle/protobuf/struct.proto\032\037google/proto"
-          + "buf/timestamp.proto\032\027google/rpc/status.p"
-          + "roto\032\034google/spanner/v1/keys.proto\032 goog"
-          + "le/spanner/v1/mutation.proto\032\"google/spa"
-          + "nner/v1/result_set.proto\032#google/spanner"
-          + "/v1/transaction.proto\032\034google/spanner/v1"
-          + "/type.proto\"~\n\024CreateSessionRequest\0229\n\010d"
-          + "atabase\030\001 \001(\tB\'\340A\002\372A!\n\037spanner.googleapi"
-          + "s.com/Database\022+\n\007session\030\002 \001(\0132\032.google"
-          + ".spanner.v1.Session\"\251\001\n\032BatchCreateSessi"
-          + "onsRequest\0229\n\010database\030\001 \001(\tB\'\340A\002\372A!\n\037sp"
-          + "anner.googleapis.com/Database\0224\n\020session"
-          + "_template\030\002 \001(\0132\032.google.spanner.v1.Sess"
-          + "ion\022\032\n\rsession_count\030\003 \001(\005B\003\340A\002\"J\n\033Batch"
-          + "CreateSessionsResponse\022+\n\007session\030\001 \003(\0132"
-          + "\032.google.spanner.v1.Session\"\344\002\n\007Session\022"
-          + "\014\n\004name\030\001 \001(\t\0226\n\006labels\030\002 \003(\0132&.google.s"
-          + "panner.v1.Session.LabelsEntry\022/\n\013create_"
-          + "time\030\003 \001(\0132\032.google.protobuf.Timestamp\022="
-          + "\n\031approximate_last_use_time\030\004 \001(\0132\032.goog"
-          + "le.protobuf.Timestamp\032-\n\013LabelsEntry\022\013\n\003"
-          + "key\030\001 \001(\t\022\r\n\005value\030\002 \001(\t:\0028\001:t\352Aq\n\036spann"
-          + "er.googleapis.com/Session\022Oprojects/{pro"
-          + "ject}/instances/{instance}/databases/{da"
-          + "tabase}/sessions/{session}\"I\n\021GetSession"
-          + "Request\0224\n\004name\030\001 \001(\tB&\340A\002\372A \n\036spanner.g"
-          + "oogleapis.com/Session\"\207\001\n\023ListSessionsRe"
-          + "quest\0229\n\010database\030\001 \001(\tB\'\340A\002\372A!\n\037spanner"
-          + ".googleapis.com/Database\022\021\n\tpage_size\030\002 "
-          + "\001(\005\022\022\n\npage_token\030\003 \001(\t\022\016\n\006filter\030\004 \001(\t\""
-          + "]\n\024ListSessionsResponse\022,\n\010sessions\030\001 \003("
-          + "\0132\032.google.spanner.v1.Session\022\027\n\017next_pa"
-          + "ge_token\030\002 \001(\t\"L\n\024DeleteSessionRequest\0224"
-          + "\n\004name\030\001 \001(\tB&\340A\002\372A \n\036spanner.googleapis"
-          + ".com/Session\"\202\005\n\021ExecuteSqlRequest\0227\n\007se"
-          + "ssion\030\001 \001(\tB&\340A\002\372A \n\036spanner.googleapis."
-          + "com/Session\022;\n\013transaction\030\002 \001(\0132&.googl"
-          + "e.spanner.v1.TransactionSelector\022\020\n\003sql\030"
-          + "\003 \001(\tB\003\340A\002\022\'\n\006params\030\004 \001(\0132\027.google.prot"
-          + "obuf.Struct\022I\n\013param_types\030\005 \003(\01324.googl"
-          + "e.spanner.v1.ExecuteSqlRequest.ParamType"
-          + "sEntry\022\024\n\014resume_token\030\006 \001(\014\022B\n\nquery_mo"
-          + "de\030\007 \001(\0162..google.spanner.v1.ExecuteSqlR"
-          + "equest.QueryMode\022\027\n\017partition_token\030\010 \001("
-          + "\014\022\r\n\005seqno\030\t \001(\003\022H\n\rquery_options\030\n \001(\0132"
-          + "1.google.spanner.v1.ExecuteSqlRequest.Qu"
-          + "eryOptions\032)\n\014QueryOptions\022\031\n\021optimizer_"
-          + "version\030\001 \001(\t\032J\n\017ParamTypesEntry\022\013\n\003key\030"
-          + "\001 \001(\t\022&\n\005value\030\002 \001(\0132\027.google.spanner.v1"
-          + ".Type:\0028\001\".\n\tQueryMode\022\n\n\006NORMAL\020\000\022\010\n\004PL"
-          + "AN\020\001\022\013\n\007PROFILE\020\002\"\337\003\n\026ExecuteBatchDmlReq"
-          + "uest\0227\n\007session\030\001 \001(\tB&\340A\002\372A \n\036spanner.g"
-          + "oogleapis.com/Session\022@\n\013transaction\030\002 \001"
-          + "(\0132&.google.spanner.v1.TransactionSelect"
-          + "orB\003\340A\002\022L\n\nstatements\030\003 \003(\01323.google.spa"
-          + "nner.v1.ExecuteBatchDmlRequest.Statement"
-          + "B\003\340A\002\022\022\n\005seqno\030\004 \001(\003B\003\340A\002\032\347\001\n\tStatement\022"
-          + "\013\n\003sql\030\001 \001(\t\022\'\n\006params\030\002 \001(\0132\027.google.pr"
-          + "otobuf.Struct\022X\n\013param_types\030\003 \003(\0132C.goo"
+          + "e.proto\032\036google/protobuf/duration.proto\032"
+          + "\033google/protobuf/empty.proto\032\034google/pro"
+          + "tobuf/struct.proto\032\037google/protobuf/time"
+          + "stamp.proto\032\027google/rpc/status.proto\032\034go"
+          + "ogle/spanner/v1/keys.proto\032 google/spann"
+          + "er/v1/mutation.proto\032\"google/spanner/v1/"
+          + "result_set.proto\032#google/spanner/v1/tran"
+          + "saction.proto\032\034google/spanner/v1/type.pr"
+          + "oto\"~\n\024CreateSessionRequest\0229\n\010database\030"
+          + "\001 \001(\tB\'\340A\002\372A!\n\037spanner.googleapis.com/Da"
+          + "tabase\022+\n\007session\030\002 \001(\0132\032.google.spanner"
+          + ".v1.Session\"\251\001\n\032BatchCreateSessionsReque"
+          + "st\0229\n\010database\030\001 \001(\tB\'\340A\002\372A!\n\037spanner.go"
+          + "ogleapis.com/Database\0224\n\020session_templat"
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-          + "/www.googleapis.com/auth/cloud-platform,"
-          + "https://www.googleapis.com/auth/spanner."
-          + "dataB\224\002\n\025com.google.spanner.v1B\014SpannerP"
-          + "rotoP\001Z8google.golang.org/genproto/googl"
-          + "eapis/spanner/v1;spanner\252\002\027Google.Cloud."
-          + "Spanner.V1\312\002\027Google\\Cloud\\Spanner\\V1\352\002\032G"
-          + "oogle::Cloud::Spanner::V1\352A_\n\037spanner.go"
-          + "ogleapis.com/Database\022<projects/{project"
-          + "}/instances/{instance}/databases/{databa"
-          + "se}b\006proto3"
+          + "bases/*/sessions/*}:streamingRead:\001*0\001\022\311"
+          + "\001\n\020BeginTransaction\022*.google.spanner.v1."
+          + "BeginTransactionRequest\032\036.google.spanner"
+          + ".v1.Transaction\"i\202\323\344\223\002Q\"L/v1/{session=pr"
+          + "ojects/*/instances/*/databases/*/session"
+          + "s/*}:beginTransaction:\001*\332A\017session,optio"
+          + "ns\022\353\001\n\006Commit\022 .google.spanner.v1.Commit"
+          + "Request\032!.google.spanner.v1.CommitRespon"
+          + "se\"\233\001\202\323\344\223\002G\"B/v1/{session=projects/*/ins"
+          + "tances/*/databases/*/sessions/*}:commit:"
+          + "\001*\332A session,transaction_id,mutations\332A("
+          + "session,single_use_transaction,mutations"
+          + "\022\260\001\n\010Rollback\022\".google.spanner.v1.Rollba"
+          + "ckRequest\032\026.google.protobuf.Empty\"h\202\323\344\223\002"
+          + "I\"D/v1/{session=projects/*/instances/*/d"
+          + "atabases/*/sessions/*}:rollback:\001*\332A\026ses"
+          + "sion,transaction_id\022\267\001\n\016PartitionQuery\022("
+          + ".google.spanner.v1.PartitionQueryRequest"
+          + "\032$.google.spanner.v1.PartitionResponse\"U"
+          + "\202\323\344\223\002O\"J/v1/{session=projects/*/instance"
+          + "s/*/databases/*/sessions/*}:partitionQue"
+          + "ry:\001*\022\264\001\n\rPartitionRead\022\'.google.spanner"
+          + ".v1.PartitionReadRequest\032$.google.spanne"
+          + "r.v1.PartitionResponse\"T\202\323\344\223\002N\"I/v1/{ses"
+          + "sion=projects/*/instances/*/databases/*/"
+          + "sessions/*}:partitionRead:\001*\032w\312A\026spanner"
+          + ".googleapis.com\322A[https://www.googleapis"
+          + ".com/auth/cloud-platform,https://www.goo"
+          + "gleapis.com/auth/spanner.dataB\224\002\n\025com.go"
+          + "ogle.spanner.v1B\014SpannerProtoP\001Z8google."
+          + "golang.org/genproto/googleapis/spanner/v"
+          + "1;spanner\252\002\027Google.Cloud.Spanner.V1\312\002\027Go"
+          + "ogle\\Cloud\\Spanner\\V1\352\002\032Google::Cloud::S"
+          + "panner::V1\352A_\n\037spanner.googleapis.com/Da"
+          + "tabase\022<projects/{project}/instances/{in"
+          + "stance}/databases/{database}b\006proto3"
     };
     descriptor =
         com.google.protobuf.Descriptors.FileDescriptor.internalBuildGeneratedFileFrom(
@@ -349,6 +357,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
               com.google.api.ClientProto.getDescriptor(),
               com.google.api.FieldBehaviorProto.getDescriptor(),
               com.google.api.ResourceProto.getDescriptor(),
+              com.google.protobuf.DurationProto.getDescriptor(),
               com.google.protobuf.EmptyProto.getDescriptor(),
               com.google.protobuf.StructProto.getDescriptor(),
               com.google.protobuf.TimestampProto.getDescriptor(),
@@ -575,7 +584,12 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_CommitRequest_descriptor,
             new java.lang.String[] {
-              "Session", "TransactionId", "SingleUseTransaction", "Mutations", "Transaction",
+              "Session",
+              "TransactionId",
+              "SingleUseTransaction",
+              "Mutations",
+              "ReturnCommitStats",
+              "Transaction",
             });
     internal_static_google_spanner_v1_CommitResponse_descriptor =
         getDescriptor().getMessageTypes().get(19);
@@ -583,7 +597,15 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
         new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
             internal_static_google_spanner_v1_CommitResponse_descriptor,
             new java.lang.String[] {
-              "CommitTimestamp",
+              "CommitTimestamp", "CommitStats",
+            });
+    internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor =
+        internal_static_google_spanner_v1_CommitResponse_descriptor.getNestedTypes().get(0);
+    internal_static_google_spanner_v1_CommitResponse_CommitStats_fieldAccessorTable =
+        new com.google.protobuf.GeneratedMessageV3.FieldAccessorTable(
+            internal_static_google_spanner_v1_CommitResponse_CommitStats_descriptor,
+            new java.lang.String[] {
+              "MutationCount",
             });
     internal_static_google_spanner_v1_RollbackRequest_descriptor =
         getDescriptor().getMessageTypes().get(20);
@@ -609,6 +631,7 @@ public static com.google.protobuf.Descriptors.FileDescriptor getDescriptor() {
     com.google.api.ClientProto.getDescriptor();
     com.google.api.FieldBehaviorProto.getDescriptor();
     com.google.api.ResourceProto.getDescriptor();
+    com.google.protobuf.DurationProto.getDescriptor();
     com.google.protobuf.EmptyProto.getDescriptor();
     com.google.protobuf.StructProto.getDescriptor();
     com.google.protobuf.TimestampProto.getDescriptor();
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/StructType.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/StructType.java
index 4658915dc6..4f68877a1d 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/StructType.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/StructType.java
@@ -130,7 +130,7 @@ public interface FieldOrBuilder
      * SQL queries, it is the column alias (e.g., `"Word"` in the
      * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
      * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-     * columns might have an empty name (e.g., !"SELECT
+     * columns might have an empty name (e.g., `"SELECT
      * UPPER(ColName)"`). Note that a query result can contain
      * multiple fields with the same name.
      * </pre>
@@ -148,7 +148,7 @@ public interface FieldOrBuilder
      * SQL queries, it is the column alias (e.g., `"Word"` in the
      * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
      * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-     * columns might have an empty name (e.g., !"SELECT
+     * columns might have an empty name (e.g., `"SELECT
      * UPPER(ColName)"`). Note that a query result can contain
      * multiple fields with the same name.
      * </pre>
@@ -311,7 +311,7 @@ public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
      * SQL queries, it is the column alias (e.g., `"Word"` in the
      * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
      * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-     * columns might have an empty name (e.g., !"SELECT
+     * columns might have an empty name (e.g., `"SELECT
      * UPPER(ColName)"`). Note that a query result can contain
      * multiple fields with the same name.
      * </pre>
@@ -340,7 +340,7 @@ public java.lang.String getName() {
      * SQL queries, it is the column alias (e.g., `"Word"` in the
      * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
      * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-     * columns might have an empty name (e.g., !"SELECT
+     * columns might have an empty name (e.g., `"SELECT
      * UPPER(ColName)"`). Note that a query result can contain
      * multiple fields with the same name.
      * </pre>
@@ -764,7 +764,7 @@ public Builder mergeFrom(
        * SQL queries, it is the column alias (e.g., `"Word"` in the
        * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
        * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-       * columns might have an empty name (e.g., !"SELECT
+       * columns might have an empty name (e.g., `"SELECT
        * UPPER(ColName)"`). Note that a query result can contain
        * multiple fields with the same name.
        * </pre>
@@ -792,7 +792,7 @@ public java.lang.String getName() {
        * SQL queries, it is the column alias (e.g., `"Word"` in the
        * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
        * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-       * columns might have an empty name (e.g., !"SELECT
+       * columns might have an empty name (e.g., `"SELECT
        * UPPER(ColName)"`). Note that a query result can contain
        * multiple fields with the same name.
        * </pre>
@@ -820,7 +820,7 @@ public com.google.protobuf.ByteString getNameBytes() {
        * SQL queries, it is the column alias (e.g., `"Word"` in the
        * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
        * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-       * columns might have an empty name (e.g., !"SELECT
+       * columns might have an empty name (e.g., `"SELECT
        * UPPER(ColName)"`). Note that a query result can contain
        * multiple fields with the same name.
        * </pre>
@@ -847,7 +847,7 @@ public Builder setName(java.lang.String value) {
        * SQL queries, it is the column alias (e.g., `"Word"` in the
        * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
        * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-       * columns might have an empty name (e.g., !"SELECT
+       * columns might have an empty name (e.g., `"SELECT
        * UPPER(ColName)"`). Note that a query result can contain
        * multiple fields with the same name.
        * </pre>
@@ -870,7 +870,7 @@ public Builder clearName() {
        * SQL queries, it is the column alias (e.g., `"Word"` in the
        * query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
        * `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-       * columns might have an empty name (e.g., !"SELECT
+       * columns might have an empty name (e.g., `"SELECT
        * UPPER(ColName)"`). Note that a query result can contain
        * multiple fields with the same name.
        * </pre>
diff --git a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
index 93de3f1b96..980f749f00 100644
--- a/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
+++ b/proto-google-cloud-spanner-v1/src/main/java/com/google/spanner/v1/TransactionOptions.java
@@ -23,10 +23,11 @@
  *
  * <pre>
  * # Transactions
- * Each session can have at most one active transaction at a time. After the
- * active transaction is completed, the session can immediately be
- * re-used for the next transaction. It is not necessary to create a
- * new session for each transaction.
+ * Each session can have at most one active transaction at a time (note that
+ * standalone reads and queries use a transaction internally and do count
+ * towards the one transaction limit). After the active transaction is
+ * completed, the session can immediately be re-used for the next transaction.
+ * It is not necessary to create a new session for each transaction.
  * # Transaction Modes
  * Cloud Spanner supports three transaction modes:
  *   1. Locking read-write. This type of transaction is the only way
@@ -4312,10 +4313,11 @@ protected Builder newBuilderForType(com.google.protobuf.GeneratedMessageV3.Build
    *
    * <pre>
    * # Transactions
-   * Each session can have at most one active transaction at a time. After the
-   * active transaction is completed, the session can immediately be
-   * re-used for the next transaction. It is not necessary to create a
-   * new session for each transaction.
+   * Each session can have at most one active transaction at a time (note that
+   * standalone reads and queries use a transaction internally and do count
+   * towards the one transaction limit). After the active transaction is
+   * completed, the session can immediately be re-used for the next transaction.
+   * It is not necessary to create a new session for each transaction.
    * # Transaction Modes
    * Cloud Spanner supports three transaction modes:
    *   1. Locking read-write. This type of transaction is the only way
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto
index 93e4987ed1..8f579e333d 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/spanner.proto
@@ -20,6 +20,7 @@ import "google/api/annotations.proto";
 import "google/api/client.proto";
 import "google/api/field_behavior.proto";
 import "google/api/resource.proto";
+import "google/protobuf/duration.proto";
 import "google/protobuf/empty.proto";
 import "google/protobuf/struct.proto";
 import "google/protobuf/timestamp.proto";
@@ -219,6 +220,12 @@ service Spanner {
   // transactions. However, it can also happen for a variety of other
   // reasons. If `Commit` returns `ABORTED`, the caller should re-attempt
   // the transaction from the beginning, re-using the same session.
+  //
+  // On very rare occasions, `Commit` might return `UNKNOWN`. This can happen,
+  // for example, if the client job experiences a 1+ hour networking failure.
+  // At that point, Cloud Spanner has lost track of the transaction outcome and
+  // we recommend that you perform another read from the database to see the
+  // state of things as they are now.
   rpc Commit(CommitRequest) returns (CommitResponse) {
     option (google.api.http) = {
       post: "/v1/{session=projects/*/instances/*/databases/*/sessions/*}:commit"
@@ -331,9 +338,8 @@ message Session {
     pattern: "projects/{project}/instances/{instance}/databases/{database}/sessions/{session}"
   };
 
-  // The name of the session. This is always system-assigned; values provided
-  // when creating a session are ignored.
-  string name = 1;
+  // Output only. The name of the session. This is always system-assigned.
+  string name = 1 [(google.api.field_behavior) = OUTPUT_ONLY];
 
   // The labels for the session.
   //
@@ -347,11 +353,11 @@ message Session {
   map<string, string> labels = 2;
 
   // Output only. The timestamp when the session is created.
-  google.protobuf.Timestamp create_time = 3;
+  google.protobuf.Timestamp create_time = 3 [(google.api.field_behavior) = OUTPUT_ONLY];
 
   // Output only. The approximate timestamp when the session is last used. It is
   // typically earlier than the actual last use time.
-  google.protobuf.Timestamp approximate_last_use_time = 4;
+  google.protobuf.Timestamp approximate_last_use_time = 4 [(google.api.field_behavior) = OUTPUT_ONLY];
 }
 
 // The request for [GetSession][google.spanner.v1.Spanner.GetSession].
@@ -438,6 +444,9 @@ message ExecuteSqlRequest {
     // SPANNER_SYS.SUPPORTED_OPTIMIZER_VERSIONS. Executing a SQL statement
     // with an invalid optimizer version will fail with a syntax error
     // (`INVALID_ARGUMENT`) status.
+    // See
+    // https://cloud.google.com/spanner/docs/query-optimizer/manage-query-optimizer
+    // for more information on managing the query optimizer.
     //
     // The `optimizer_version` statement hint has precedence over this setting.
     string optimizer_version = 1;
@@ -483,8 +492,9 @@ message ExecuteSqlRequest {
   // Parameter names and values that bind to placeholders in the SQL string.
   //
   // A parameter placeholder consists of the `@` character followed by the
-  // parameter name (for example, `@firstName`). Parameter names can contain
-  // letters, numbers, and underscores.
+  // parameter name (for example, `@firstName`). Parameter names must conform
+  // to the naming requirements of identifiers as specified at
+  // https://cloud.google.com/spanner/docs/lexical#identifiers.
   //
   // Parameters can appear anywhere that a literal value is expected.  The same
   // parameter name can be used more than once, for example:
@@ -884,12 +894,34 @@ message CommitRequest {
   // mutations are applied atomically, in the order they appear in
   // this list.
   repeated Mutation mutations = 4;
+
+  // If `true`, then statistics related to the transaction will be included in
+  // the [CommitResponse][google.spanner.v1.CommitResponse.commit_stats]. Default value is
+  // `false`.
+  bool return_commit_stats = 5;
 }
 
 // The response for [Commit][google.spanner.v1.Spanner.Commit].
 message CommitResponse {
+  // Additional statistics about a commit.
+  message CommitStats {
+    // The total number of mutations for the transaction. Knowing the
+    // `mutation_count` value can help you maximize the number of mutations
+    // in a transaction and minimize the number of API round trips. You can
+    // also monitor this value to prevent transactions from exceeding the system
+    // [limit](http://cloud.google.com/spanner/quotas#limits_for_creating_reading_updating_and_deleting_data).
+    // If the number of mutations exceeds the limit, the server returns
+    // [INVALID_ARGUMENT](http://cloud.google.com/spanner/docs/reference/rest/v1/Code#ENUM_VALUES.INVALID_ARGUMENT).
+    int64 mutation_count = 1;
+  }
+
   // The Cloud Spanner timestamp at which the transaction committed.
   google.protobuf.Timestamp commit_timestamp = 1;
+
+  // The statistics about this Commit. Not returned by default.
+  // For more information, see
+  // [CommitRequest.return_commit_stats][google.spanner.v1.CommitRequest.return_commit_stats].
+  CommitStats commit_stats = 2;
 }
 
 // The request for [Rollback][google.spanner.v1.Spanner.Rollback].
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
index 0bcbfcf900..2cafefcb10 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/transaction.proto
@@ -31,10 +31,11 @@ option ruby_package = "Google::Cloud::Spanner::V1";
 // # Transactions
 //
 //
-// Each session can have at most one active transaction at a time. After the
-// active transaction is completed, the session can immediately be
-// re-used for the next transaction. It is not necessary to create a
-// new session for each transaction.
+// Each session can have at most one active transaction at a time (note that
+// standalone reads and queries use a transaction internally and do count
+// towards the one transaction limit). After the active transaction is
+// completed, the session can immediately be re-used for the next transaction.
+// It is not necessary to create a new session for each transaction.
 //
 // # Transaction Modes
 //
diff --git a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/type.proto b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/type.proto
index 1e5e5ff313..1b863c0fdf 100644
--- a/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/type.proto
+++ b/proto-google-cloud-spanner-v1/src/main/proto/google/spanner/v1/type.proto
@@ -50,7 +50,7 @@ message StructType {
     // SQL queries, it is the column alias (e.g., `"Word"` in the
     // query `"SELECT 'hello' AS Word"`), or the column name (e.g.,
     // `"ColName"` in the query `"SELECT ColName FROM Table"`). Some
-    // columns might have an empty name (e.g., !"SELECT
+    // columns might have an empty name (e.g., `"SELECT
     // UPPER(ColName)"`). Note that a query result can contain
     // multiple fields with the same name.
     string name = 1;
diff --git a/synth.metadata b/synth.metadata
index 0a94795849..554bb0a42c 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -4,15 +4,15 @@
       "git": {
         "name": ".",
         "remote": "https://github.com/googleapis/java-spanner.git",
-        "sha": "15052653993a3924037b2c4ba27e04f553493885"
+        "sha": "4aa770ce669404ad0eca542ae5bd32a421748c18"
       }
     },
     {
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "91e206bcfeaf8948ea03fe3cb1b7616108496cd3",
-        "internalRef": "350949863"
+        "sha": "8fa381b7138f1d72966ff20563efae1b2194d359",
+        "internalRef": "353145174"
       }
     },
     {