/// <summary>
/// A long-running loop performing pool maintenance. Each iteration runs <see cref="MaintainPool"/>.
/// This is a static method to allow the target pool to be garbage collected, at which point the
/// method will complete. (This method only retains a week reference to the specified pool.)
/// </summary>
/// <param name="pool">The pool to maintain.</param>
/// <returns>A task which completes when the maintenance loop has finished, due to the session pool being
/// garbage collected</returns>
private static async Task PoolMaintenanceLoop(SessionPool pool)
{
// Keep a weak reference so that the pool can be garbage collected and we can stop the
// maintenance task.
var weakRef = new WeakReference <SessionPool>(pool);
// Make sure that even if the pool variable is captured due to compiler implementation details,
// it won't prevent garbage collection.
pool = null;
while (true)
{
if (!weakRef.TryGetTarget(out var localPool))
{
return;
}
try
{
localPool.MaintainPool();
}
catch (Exception e)
{
localPool._logger.Error($"Error running {nameof(SessionPool)} maintenance task", e);
}
var scheduler = localPool._scheduler;
var delay = localPool.Options.MaintenanceLoopDelay;
// Allow the pool to be collected while we're waiting.
localPool = null;
await scheduler.Delay(delay, CancellationToken.None).ConfigureAwait(false);
}
}
internal static bool CheckForSessionExpiredError(this RpcException rpcException, Func <Session> sessionFunc)
{
if (rpcException.IsSessionExpiredError())
{
SessionPool.MarkSessionExpired(sessionFunc());
}
return(false);
}
internal TargetedSessionPool(SessionPool parent, DatabaseName databaseName, bool acquireSessionsImmediately) : base(parent)
{
_databaseName = GaxPreconditions.CheckNotNull(databaseName, nameof(databaseName));
_createSessionRequest = new CreateSessionRequest {
DatabaseAsDatabaseName = databaseName
};
if (acquireSessionsImmediately)
{
StartAcquisitionTasksIfNecessary();
}
}
internal DetachedSessionPool(SessionPool parent) : base(parent)
{
}
protected SessionPoolBase(SessionPool parent) => Parent = parent;
