diff --git a/src/Spanner/CommitResponse.php b/src/Spanner/CommitResponse.php
index 62b51919356..26ebc81e79a 100644
--- a/src/Spanner/CommitResponse.php
+++ b/src/Spanner/CommitResponse.php
@@ -19,6 +19,60 @@
 
 class CommitResponse extends \Google\Model
 {
+  /**
+   * Default value. If the value is not specified, the `SERIALIZABLE` isolation
+   * level is used.
+   */
+  public const ISOLATION_LEVEL_ISOLATION_LEVEL_UNSPECIFIED = 'ISOLATION_LEVEL_UNSPECIFIED';
+  /**
+   * All transactions appear as if they executed in a serial order, even if some
+   * of the reads, writes, and other operations of distinct transactions
+   * actually occurred in parallel. Spanner assigns commit timestamps that
+   * reflect the order of committed transactions to implement this property.
+   * Spanner offers a stronger guarantee than serializability called external
+   * consistency. For more information, see [TrueTime and external
+   * consistency](https://cloud.google.com/spanner/docs/true-time-external-
+   * consistency#serializability).
+   */
+  public const ISOLATION_LEVEL_SERIALIZABLE = 'SERIALIZABLE';
+  /**
+   * All reads performed during the transaction observe a consistent snapshot of
+   * the database, and the transaction is only successfully committed in the
+   * absence of conflicts between its updates and any concurrent updates that
+   * have occurred since that snapshot. Consequently, in contrast to
+   * `SERIALIZABLE` transactions, only write-write conflicts are detected in
+   * snapshot transactions. This isolation level does not support read-only and
+   * partitioned DML transactions. When `REPEATABLE_READ` is specified on a
+   * read-write transaction, the locking semantics default to `OPTIMISTIC`.
+   */
+  public const ISOLATION_LEVEL_REPEATABLE_READ = 'REPEATABLE_READ';
+  /**
+   * Default value. * If isolation level is SERIALIZABLE, locking semantics
+   * default to `PESSIMISTIC`. * If isolation level is REPEATABLE_READ, locking
+   * semantics default to `OPTIMISTIC`. * See [Concurrency
+   * control](https://cloud.google.com/spanner/docs/concurrency-control) for
+   * more details.
+   */
+  public const READ_LOCK_MODE_READ_LOCK_MODE_UNSPECIFIED = 'READ_LOCK_MODE_UNSPECIFIED';
+  /**
+   * Pessimistic lock mode. Lock acquisition behavior depends on the isolation
+   * level in use. In SERIALIZABLE isolation, reads and writes acquire necessary
+   * locks during transaction statement execution. In REPEATABLE_READ isolation,
+   * reads that explicitly request to be locked and writes acquire locks. See
+   * [Concurrency control](https://cloud.google.com/spanner/docs/concurrency-
+   * control) for details on the types of locks acquired at each transaction
+   * step.
+   */
+  public const READ_LOCK_MODE_PESSIMISTIC = 'PESSIMISTIC';
+  /**
+   * Optimistic lock mode. Lock acquisition behavior depends on the isolation
+   * level in use. In both SERIALIZABLE and REPEATABLE_READ isolation, reads and
+   * writes do not acquire locks during transaction statement execution. See
+   * [Concurrency control](https://cloud.google.com/spanner/docs/concurrency-
+   * control) for details on how the guarantees of each isolation level are
+   * provided at commit time.
+   */
+  public const READ_LOCK_MODE_OPTIMISTIC = 'OPTIMISTIC';
   protected $commitStatsType = CommitStats::class;
   protected $commitStatsDataType = '';
   /**
@@ -27,8 +81,20 @@ class CommitResponse extends \Google\Model
    * @var string
    */
   public $commitTimestamp;
+  /**
+   * The isolation level used for the read-write transaction.
+   *
+   * @var string
+   */
+  public $isolationLevel;
   protected $precommitTokenType = MultiplexedSessionPrecommitToken::class;
   protected $precommitTokenDataType = '';
+  /**
+   * The read lock mode used for the read-write transaction.
+   *
+   * @var string
+   */
+  public $readLockMode;
   /**
    * If `TransactionOptions.isolation_level` is set to
    * `IsolationLevel.REPEATABLE_READ`, then the snapshot timestamp is the
@@ -72,6 +138,24 @@ public function getCommitTimestamp()
   {
     return $this->commitTimestamp;
   }
+  /**
+   * The isolation level used for the read-write transaction.
+   *
+   * Accepted values: ISOLATION_LEVEL_UNSPECIFIED, SERIALIZABLE, REPEATABLE_READ
+   *
+   * @param self::ISOLATION_LEVEL_* $isolationLevel
+   */
+  public function setIsolationLevel($isolationLevel)
+  {
+    $this->isolationLevel = $isolationLevel;
+  }
+  /**
+   * @return self::ISOLATION_LEVEL_*
+   */
+  public function getIsolationLevel()
+  {
+    return $this->isolationLevel;
+  }
   /**
    * If specified, transaction has not committed yet. You must retry the commit
    * with the new precommit token.
@@ -89,6 +173,24 @@ public function getPrecommitToken()
   {
     return $this->precommitToken;
   }
+  /**
+   * The read lock mode used for the read-write transaction.
+   *
+   * Accepted values: READ_LOCK_MODE_UNSPECIFIED, PESSIMISTIC, OPTIMISTIC
+   *
+   * @param self::READ_LOCK_MODE_* $readLockMode
+   */
+  public function setReadLockMode($readLockMode)
+  {
+    $this->readLockMode = $readLockMode;
+  }
+  /**
+   * @return self::READ_LOCK_MODE_*
+   */
+  public function getReadLockMode()
+  {
+    return $this->readLockMode;
+  }
   /**
    * If `TransactionOptions.isolation_level` is set to
    * `IsolationLevel.REPEATABLE_READ`, then the snapshot timestamp is the
diff --git a/src/Spanner/InstancePartition.php b/src/Spanner/InstancePartition.php
index be5c947a66e..c6e2829fd1f 100644
--- a/src/Spanner/InstancePartition.php
+++ b/src/Spanner/InstancePartition.php
@@ -86,6 +86,8 @@ class InstancePartition extends \Google\Collection
   /**
    * The number of nodes allocated to this instance partition. Users can set the
    * `node_count` field to specify the target number of nodes allocated to the
+   * instance partition. If autoscaling is enabled, node_count is treated as an
+   * OUTPUT_ONLY field and reflects the current number of nodes allocated to the
    * instance partition. This may be zero in API responses for instance
    * partitions that are not yet in state `READY`.
    *
@@ -95,9 +97,11 @@ class InstancePartition extends \Google\Collection
   /**
    * The number of processing units allocated to this instance partition. Users
    * can set the `processing_units` field to specify the target number of
-   * processing units allocated to the instance partition. This might be zero in
-   * API responses for instance partitions that are not yet in the `READY`
-   * state.
+   * processing units allocated to the instance partition. If autoscaling is
+   * enabled, processing_units is treated as an OUTPUT_ONLY field and reflects
+   * the current number of processing units allocated to the instance partition.
+   * This might be zero in API responses for instance partitions that are not
+   * yet in the `READY` state.
    *
    * @var int
    */
@@ -253,6 +257,8 @@ public function getName()
   /**
    * The number of nodes allocated to this instance partition. Users can set the
    * `node_count` field to specify the target number of nodes allocated to the
+   * instance partition. If autoscaling is enabled, node_count is treated as an
+   * OUTPUT_ONLY field and reflects the current number of nodes allocated to the
    * instance partition. This may be zero in API responses for instance
    * partitions that are not yet in state `READY`.
    *
@@ -272,9 +278,11 @@ public function getNodeCount()
   /**
    * The number of processing units allocated to this instance partition. Users
    * can set the `processing_units` field to specify the target number of
-   * processing units allocated to the instance partition. This might be zero in
-   * API responses for instance partitions that are not yet in the `READY`
-   * state.
+   * processing units allocated to the instance partition. If autoscaling is
+   * enabled, processing_units is treated as an OUTPUT_ONLY field and reflects
+   * the current number of processing units allocated to the instance partition.
+   * This might be zero in API responses for instance partitions that are not
+   * yet in the `READY` state.
    *
    * @param int $processingUnits
    */