Interface Session

Version 6.21.2

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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.

Cloud Spanner limits the number of sessions that can exist at any given time; thus, 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.

Implements

DatabaseClient, AutoCloseable

Methods

asyncClose()

public abstract ApiFuture<Empty> asyncClose()

Closes the session asynchronously and returns the ApiFuture that can be used to monitor the operation progress.

Returns

Type	Description
ApiFuture<Empty>

close()

public abstract void close()

getName()

public abstract String getName()

Returns the resource name associated with this session.

Returns

Type	Description
String

prepareReadWriteTransaction()

public abstract void prepareReadWriteTransaction()

Prepares a transaction for use by a subsequent #readWriteTransaction() or #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.