/// <summary>
/// Ctor.
/// </summary>
/// <param name="storagePath">Base path to store persisted data. If null data will not be written to disk.</param>
/// <param name="shutdownEvent">Event to trigger when shutdown is desired. If null no event is triggered.</param>
/// <param name="preferredPrivateMemorySizeMB">Preferred working set size for the current process in MB. Above this size data will be released and garbage will be collected.</param>
/// <param name="maximumPrivateMemorySizeMB">Maximum working set size for the current process in MB. Above this size the shutdownEvent will be triggered.</param>
/// <param name="maintenanceParallelismLimit">Maximum parallel threads for periodic data maintenance (e.g. compaction).</param>
public DataManager(string storagePath, ManualResetEventSlim shutdownEvent, ulong preferredPrivateMemorySizeMB,
ulong maximumPrivateMemorySizeMB, int maintenanceParallelismLimit)
{
// just in case our hosting process has not force-compiled the schemas, we do so here as a catch-all
Schemas.Precompile();
if (!string.IsNullOrEmpty(storagePath))
{
if (!Path.IsPathRooted(storagePath))
{
throw new ArgumentException("Path must be rooted", "storagePath");
}
if (!Directory.Exists(storagePath))
{
Directory.CreateDirectory(storagePath);
}
}
if (maintenanceParallelismLimit <= 0)
{
maintenanceParallelismLimit = Environment.ProcessorCount;
}
this.shutdownEvent = shutdownEvent;
this.StoragePath = storagePath;
if (maximumPrivateMemorySizeMB > 0)
{
if (shutdownEvent == null)
{
throw new ArgumentNullException("shutdownEvent",
"Cannot set max working set size without shutdown event.");
}
if (maximumPrivateMemorySizeMB < preferredPrivateMemorySizeMB)
{
throw new ArgumentException("Maximum working set size is smaller than preferred.",
"maximumPrivateMemorySizeMB");
}
if (preferredPrivateMemorySizeMB == 0)
{
preferredPrivateMemorySizeMB = maximumPrivateMemorySizeMB;
}
this.maximumPrivateMemorySizeMB = maximumPrivateMemorySizeMB;
this.preferredPrivateMemorySizeMB = preferredPrivateMemorySizeMB;
}
else if (preferredPrivateMemorySizeMB > 0)
{
throw new ArgumentException("Cannot set preferred working set size without max", "preferredPrivateMemorySizeMB");
}
this.CompactionConfiguration = new DataCompactionConfiguration();
this.SealTime = DefaultSealTime;
this.MaximumDataAge = DefaultMaximumDataAge;
this.taskRunner = new SemaphoreTaskRunner(maintenanceParallelismLimit);
// This is a really ridiculous hack to get the full machine name of the current system. Sigh.
this.LocalSourceName = Dns.GetHostEntry("localhost").HostName;
//this.CompactionConfiguration = new DataCompactionConfig();
this.maintenanceTimer = new Timer(_ => this.PeriodicMaintenance(), null, TimeSpan.Zero,
this.MaintenanceInterval);
// TODO: configurable, for now:
// 128KB blocks, 1MB large buffer multiples, 128MB max stream
this.MemoryStreamManager = new RecyclableMemoryStreamManager(1 << 17, 1 << 20, 1 << 27);
this.MemoryStreamManager.AggressiveBufferReturn = true;
// If we got a memory limit put a cap on free data
if (this.preferredPrivateMemorySizeMB > 4)
{
var memoryPerPool = (long)this.preferredPrivateMemorySizeMB / 2;
this.MemoryStreamManager.MaximumFreeLargePoolBytes =
this.MemoryStreamManager.MaximumFreeSmallPoolBytes = memoryPerPool / 2;
}
}