/// <summary>
/// Allocates a session from the pool if possible, or creates a new Spanner Session.
/// </summary>
/// <param name="spannerClient">The client to associate with the session. Must not be null.</param>
/// <param name="project">The project of the session. Must not be null.</param>
/// <param name="spannerInstance">The instance of the session. Must not be null.</param>
/// <param name="spannerDatabase">The database of the session. Must not be null.</param>
/// <param name="options">The transaction options for the session. Must not be null.</param>
/// <param name="cancellationToken">A cancellation token for the asynchronous operation.</param>
/// <returns>A task which, when completed, will return the session.</returns>
public async Task <Session> CreateSessionFromPoolAsync(
SpannerClient spannerClient,
string project,
string spannerInstance,
string spannerDatabase,
TransactionOptions options,
CancellationToken cancellationToken)
{
GaxPreconditions.CheckNotNull(spannerClient, nameof(spannerClient));
GaxPreconditions.CheckNotNull(project, nameof(project));
GaxPreconditions.CheckNotNull(spannerInstance, nameof(spannerInstance));
GaxPreconditions.CheckNotNull(spannerDatabase, nameof(spannerDatabase));
GaxPreconditions.CheckNotNull(options, nameof(options));
await StartSessionCreatingAsync(cancellationToken).ConfigureAwait(false);
Session sessionResult = null;
SessionPoolKey sessionPoolKey = default;
try
{
sessionPoolKey = new SessionPoolKey(spannerClient, project, spannerInstance, spannerDatabase);
SessionPoolImpl targetPool = _poolByClientAndDatabase.GetOrAdd(sessionPoolKey, key => new SessionPoolImpl(key, Options));
sessionResult = await targetPool.AcquireSessionAsync(options, cancellationToken).ConfigureAwait(false);
// Refresh the MRU list which tells us what sessions need to be trimmed from the pool when we want
// to add another poolEntry.
return(sessionResult);
}
finally
{
EndSessionCreating(sessionResult, sessionPoolKey);
}
}
private static void ReSortMru(SessionPoolImpl targetPool)
{
lock (s_priorityListSync)
{
if (s_priorityList.Count > 1)
{
s_priorityList.Remove(targetPool);
s_priorityList.Add(targetPool, targetPool);
}
}
}
// Only present for testing.
internal int GetPoolSize(SpannerClient spannerClient, string project, string spannerInstance, string spannerDatabase)
{
GaxPreconditions.CheckNotNull(spannerClient, nameof(spannerClient));
GaxPreconditions.CheckNotNull(project, nameof(project));
GaxPreconditions.CheckNotNull(spannerInstance, nameof(spannerInstance));
GaxPreconditions.CheckNotNull(spannerDatabase, nameof(spannerDatabase));
var sessionPoolKey = new SessionPoolKey(spannerClient, project, spannerInstance, spannerDatabase);
SessionPoolImpl targetPool = _poolByClientAndDatabase.GetOrAdd(sessionPoolKey, key => new SessionPoolImpl(key, Options));
return(targetPool.GetPoolSize());
}
/// <summary>
/// Releases a session back into the pool, possibly causing another entry to be evicted if the maximum pool size has been
/// reached.
/// </summary>
/// <param name="session"></param>
/// <param name="client"></param>
/// <returns></returns>
public static void ReleaseToPool(this SpannerClient client, Session session)
{
session.ThrowIfNull(nameof(session));
SessionPoolKey poolKey;
if (s_sessionsInUse.TryRemove(session, out poolKey))
{
LogSessionsInUse();
SignalAnyWaitingRequests();
if (IsSessionExpired(session))
{
bool unused;
s_blackListedSessions.TryRemove(session.Name, out unused);
return;
}
SessionPoolImpl targetPool = s_poolByClientAndDatabase.GetOrAdd(poolKey,
key => new SessionPoolImpl(key));
SpannerClient evictionClient = poolKey.Client;
Session evictionSession = null;
//Figure out if we want to pool this released session.
lock (s_priorityListSync)
{
targetPool.ReleaseSessionToPool(client, session);
if (CurrentPooledSessions > MaximumPooledSessions)
{
var evictionPool = s_priorityList.First().Value;
evictionClient = evictionPool.Key.Client;
evictionSession = evictionPool.AcquireEvictionCandidate();
ReSortMru(evictionPool);
}
ReSortMru(targetPool);
}
if (evictionSession != null)
{
Task.Run(() => EvictSessionAsync(evictionClient, evictionSession));
}
}
else
{
Logger.Error(
() =>
"An attempt was made to release a session to the pool,"
+ " but the session was not originally allocated from the pool.");
}
}
internal int GetPoolSize(
SpannerClient spannerClient,
string project,
string spannerInstance,
string spannerDatabase)
{
project.ThrowIfNullOrEmpty(nameof(project));
spannerInstance.ThrowIfNullOrEmpty(nameof(spannerInstance));
spannerDatabase.ThrowIfNullOrEmpty(nameof(spannerDatabase));
var sessionPoolKey = new SessionPoolKey(spannerClient,
project,
spannerInstance,
spannerDatabase);
SessionPoolImpl targetPool = _poolByClientAndDatabase.GetOrAdd(sessionPoolKey,
key => new SessionPoolImpl(key, Options));
return(targetPool.GetPoolSize());
}
/// <summary>
/// Allocates a session from the pool if possible, or creates a new Spanner Session.
/// </summary>
/// <param name="spannerClient"></param>
/// <param name="project"></param>
/// <param name="spannerInstance"></param>
/// <param name="spannerDatabase"></param>
/// <param name="options"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
public static async Task <Session> CreateSessionFromPoolAsync(
this SpannerClient spannerClient,
string project,
string spannerInstance,
string spannerDatabase,
TransactionOptions options,
CancellationToken cancellationToken)
{
project.ThrowIfNullOrEmpty(nameof(project));
spannerInstance.ThrowIfNullOrEmpty(nameof(spannerInstance));
spannerDatabase.ThrowIfNullOrEmpty(nameof(spannerDatabase));
await StartSessionCreatingAsync(cancellationToken).ConfigureAwait(false);
Session sessionResult = null;
SessionPoolKey sessionPoolKey = default(SessionPoolKey);
try
{
sessionPoolKey = new SessionPoolKey(spannerClient,
project,
spannerInstance,
spannerDatabase);
SessionPoolImpl targetPool = s_poolByClientAndDatabase.GetOrAdd(sessionPoolKey,
key => new SessionPoolImpl(key));
sessionResult = await targetPool.AcquireSessionAsync(options, cancellationToken).ConfigureAwait(false);
//refresh the mru list which tells us what sessions need to be trimmed from the pool when we want
// to add another poolEntry.
ReSortMru(targetPool);
return(sessionResult);
} finally
{
EndSessionCreating(sessionResult, sessionPoolKey);
}
}
