Google Cloud Spanner v1 API - Class SessionPool (4.5.0)

public sealed class SessionPool

Reference documentation and code samples for the Google Cloud Spanner v1 API class SessionPool.

A pool of sessions associated with a SpannerClient. Sessions can be acquired by specifying the desired transaction options, if any. A session/transaction pair is then returned, which should be returned to the pool when it is no longer required. Sessions are kept alive automatically, and retired if they are expired by the server.

Inheritance

object > SessionPool

Inherited Members

object.GetHashCode()

object.GetType()

object.ToString()

Namespace

Google.Cloud.Spanner.V1

Assembly

Google.Cloud.Spanner.V1.dll

Constructors

SessionPool(SpannerClient, SessionPoolOptions)

public SessionPool(SpannerClient client, SessionPoolOptions options)

Creates a session pool for the given client.

Parameters
Name	Description
`client`	`SpannerClient` The client to use for this session pool. Must not be null.
`options`	`SessionPoolOptions` The options for this session pool. Must not be null.

Properties

Options

public SessionPoolOptions Options { get; }

The options governing this session pool.

Property Value
Type	Description
`SessionPoolOptions`

Methods

AcquireSessionAsync(DatabaseName, TransactionOptions, CancellationToken)

public Task<PooledSession> AcquireSessionAsync(DatabaseName databaseName, TransactionOptions transactionOptions, CancellationToken cancellationToken)

Asynchronously acquires a session, potentially associated with a transaction. This is equivalent to calling AcquireSessionAsync(SessionPoolSegmentKey, TransactionOptions, CancellationToken) passing a segment key with a null database role.

Parameters
Name	Description
`databaseName`	`Google.Cloud.Spanner.Common.V1.DatabaseName` The name of the database to acquire the session for.
`transactionOptions`	`TransactionOptions` The transaction options required for the session. After the operation completes, this value is no longer used, so modifications to the object will not affect the transaction. May be null.
`cancellationToken`	`CancellationToken` An optional token for canceling the call.

Returns
Type	Description
`TaskPooledSession`	The PooledSession representing the client, session and transaction.

AcquireSessionAsync(SessionPoolSegmentKey, TransactionOptions, CancellationToken)

public Task<PooledSession> AcquireSessionAsync(SessionPool.SessionPoolSegmentKey key, TransactionOptions transactionOptions, CancellationToken cancellationToken)

Asynchronously acquires a session using the given SessionPool.SessionPoolSegmentKey, potentially associated with a transaction.

Parameters
Name	Description
`key`	`SessionPoolSessionPoolSegmentKey` The SessionPool.SessionPoolSegmentKey to acquire the session.
`transactionOptions`	`TransactionOptions` The transaction options required for the session. After the operation completes, this value is no longer used, so modifications to the object will not affect the transaction. May be null.
`cancellationToken`	`CancellationToken` An optional token for canceling the call.

Returns
Type	Description
`TaskPooledSession`	The PooledSession representing the client, session and transaction.

CreateDetachedSession(SessionName, ByteString, ModeOneofCase)

public PooledSession CreateDetachedSession(SessionName sessionName, ByteString transactionId, TransactionOptions.ModeOneofCase transactionMode)

Creates a PooledSession with a known name and transaction ID/mode, with the client associated with this pool, but is otherwise not part of this pool. This method does not query the server for the session state. When the returned PooledSession is released, it will not become part of this pool, and the transaction will not be rolled back.

Parameters
Name	Description
`sessionName`	`SessionName` The name of the transaction. Must not be null.
`transactionId`	`ByteString` The ID of the transaction. Must not be null.
`transactionMode`	`TransactionOptionsModeOneofCase` The mode of the transaction.

Returns
Type	Description
`PooledSession`	A PooledSession for the given session and transaction.

Remarks

This is typically used for partitioned queries, where the same session is used across multiple machines, so should not be reused by the pool.

CreateDetachedSession(SessionName, ByteString, ModeOneofCase, Timestamp)

public PooledSession CreateDetachedSession(SessionName sessionName, ByteString transactionId, TransactionOptions.ModeOneofCase transactionMode, Timestamp readTimestamp)

Parameters
Name	Description
`sessionName`	`SessionName` The name of the transaction. Must not be null.
`transactionId`	`ByteString` The ID of the transaction. Must not be null.
`transactionMode`	`TransactionOptionsModeOneofCase` The mode of the transaction.
`readTimestamp`	`Timestamp` The read timestamp of the transaction.

Returns
Type	Description
`PooledSession`	A PooledSession for the given session and transaction.

Remarks

This is typically used for partitioned queries, where the same session is used across multiple machines, so should not be reused by the pool.

GetSegmentStatisticsSnapshot(DatabaseName)

public SessionPool.SessionPoolSegmentStatistics GetSegmentStatisticsSnapshot(DatabaseName databaseName)

Provides a snapshot of statistics for the pool associated with the given database. This is equivalent to calling GetSegmentStatisticsSnapshot(SessionPoolSegmentKey) passing a segment key with a null database role.

Parameter
Name	Description
`databaseName`	`Google.Cloud.Spanner.Common.V1.DatabaseName`

Returns
Type	Description
`SessionPoolSessionPoolSegmentStatistics`	A snapshot of statistics for this pool.

GetSegmentStatisticsSnapshot(SessionPoolSegmentKey)

public SessionPool.SessionPoolSegmentStatistics GetSegmentStatisticsSnapshot(SessionPool.SessionPoolSegmentKey key)

Provides a snapshot of statistics for the pool associated with the given SessionPool.SessionPoolSegmentKey.

Parameter
Name	Description
`key`	`SessionPoolSessionPoolSegmentKey`

Returns
Type	Description
`SessionPoolSessionPoolSegmentStatistics`	A snapshot of statistics for this pool.

GetStatisticsSnapshot()

public SessionPool.Statistics GetStatisticsSnapshot()

Provides a snapshot of statistics for this pool.

Returns
Type	Description
`SessionPoolStatistics`	A snapshot of statistics for this pool.

GetStatisticsSnapshot(DatabaseName)

[Obsolete("Use the overload GetSegmentStatisticsSnapshot(DatabaseName) instead.")]
public SessionPool.DatabaseStatistics GetStatisticsSnapshot(DatabaseName databaseName)

Provides a snapshot of statistics for a database-specific pool. This is equivalent to calling GetSegmentStatisticsSnapshot(SessionPoolSegmentKey) passing a segment key with a null database role.

Parameter
Name	Description
`databaseName`	`Google.Cloud.Spanner.Common.V1.DatabaseName`

Returns
Type	Description
`SessionPoolDatabaseStatistics`	A snapshot of statistics for this pool.

ShutdownPoolAsync(DatabaseName, CancellationToken)

public Task ShutdownPoolAsync(DatabaseName databaseName, CancellationToken cancellationToken)

Shuts down the session pool associated with the given database name. Further attempts to acquire sessions will fail immediately. This is equivalent to calling ShutdownPoolAsync(SessionPoolSegmentKey, CancellationToken) passing a segment key with a null database role.

Parameters
Name	Description
`databaseName`	`Google.Cloud.Spanner.Common.V1.DatabaseName` The database whose session pool should be shut down. Must not be null.
`cancellationToken`	`CancellationToken` An optional token for canceling the returned task. This does not cancel the shutdown itself.

Returns
Type	Description
`Task`	A task which will complete when the session pool has finished shutting down.

Remarks

This call will delete all pooled sessions, and wait for all active sessions to be released back to the pool and also deleted.

ShutdownPoolAsync(SessionPoolSegmentKey, CancellationToken)

public Task ShutdownPoolAsync(SessionPool.SessionPoolSegmentKey key, CancellationToken cancellationToken)

Shuts down the session pool of the given SessionPoolSegmentKey. Further attempts to acquire sessions will fail immediately.

Parameters
Name	Description
`key`	`SessionPoolSessionPoolSegmentKey` The SessionPool.SessionPoolSegmentKey whose session pool should be shutdown.
`cancellationToken`	`CancellationToken` An optional token for canceling the returned task. This does not cancel the shutdown itself.

Returns
Type	Description
`Task`	A task which will complete when the session pool has finished shutting down.

Remarks

This call will delete all pooled sessions, and wait for all active sessions to be released back to the pool and also deleted.

WhenPoolReady(DatabaseName, CancellationToken)

public Task WhenPoolReady(DatabaseName databaseName, CancellationToken cancellationToken = default)

Returns a task indicating when the session pool associated with the given database name is populated up to its minimum size. This is equivalent to calling WhenPoolReady(SessionPoolSegmentKey, CancellationToken) passing a segment key with a null database role.

Parameters
Name	Description
`databaseName`	`Google.Cloud.Spanner.Common.V1.DatabaseName` The database whose session pool should be populated. Must not be null.
`cancellationToken`	`CancellationToken` An optional token for canceling the call.

Returns
Type	Description
`Task`	A task which will complete when the session pool has reached its minimum size.

Remarks

If the pool is unhealthy or becomes unhealthy before it reaches its minimum size, the returned task will be faulted with an RpcException.

WhenPoolReady(SessionPoolSegmentKey, CancellationToken)

public Task WhenPoolReady(SessionPool.SessionPoolSegmentKey key, CancellationToken cancellationToken = default)

Returns a task indicating when the session pool for the given SessionPool.SessionPoolSegmentKey is populated up to its minimum size.

Parameters
Name	Description
`key`	`SessionPoolSessionPoolSegmentKey` The SessionPool.SessionPoolSegmentKey whose session pool should be populated.
`cancellationToken`	`CancellationToken` An optional token for canceling the call.

Returns
Type	Description
`Task`	A task which will complete when the session pool has reached its minimum size.

Remarks

If the pool is unhealthy or becomes unhealthy before it reaches its minimum size, the returned task will be faulted with an RpcException.