Package com.google.cloud.spanner

Interface Session

All Superinterfaces:
AutoCloseable, DatabaseClient
@InternalApi public interface Session extends DatabaseClient, AutoCloseable
A Session can be used to perform transactions that read and/or modify data in a Cloud Spanner database.

Sessions can only execute one transaction at a time. To execute multiple concurrent read-write/write-only transactions, create multiple sessions. Note that standalone reads and queries use a transaction internally, and count toward the one transaction limit.

It is a good idea to delete idle and/or unneeded sessions. Aside from explicit deletes, Cloud Spanner can delete sessions for which no operations are sent for more than an hour, or due to internal errors. If a session is deleted, requests to it return ErrorCode.NOT_FOUND.

Idle sessions can be kept alive by sending a trivial SQL query periodically, for example, SELECT 1.

Sessions are long-lived objects intended to be reused for many consecutive operations; a typical application will maintain a pool of sessions to use during its lifetime.

Since only one transaction can be performed at a time within any given session, instances require external synchronization; Session implementations are not required to be thread-safe.

  • Method Details

    • getName

      String getName()
      Returns the resource name associated with this session.

    • prepareReadWriteTransaction

      void prepareReadWriteTransaction()
      Prepares a transaction for use by a subsequent DatabaseClient.readWriteTransaction(TransactionOption...) or DatabaseClient.write(Iterable) call. It is not necessary to call this method before running a transaction or performing a write, but doing so may allow one round trip of the protocol to be performed in advance; calling this method on an idle session that is expected to execute a transaction or write in the near future may reduce the latency of the subsequent transaction/write.

    • close

      void close()
      Specified by:
      close in interface AutoCloseable

    • asyncClose

      com.google.api.core.ApiFuture<com.google.protobuf.Empty> asyncClose()
      Closes the session asynchronously and returns the ApiFuture that can be used to monitor the operation progress.