private async Task CommitIfRelevant(ProjectionPosition p)
{
if (!BatchingPolicy.ShouldCommit(p))
{
return;
}
await CommitState();
if (p.LooksLikeLatestAvailableInput())
{
//performance testing:
var now = DateTimeOffset.UtcNow;
var timeSpentCatchingUp = now - _startedCatchingUpAt;
Console.WriteLine($"Time taken to restore state of projection: {timeSpentCatchingUp.TotalSeconds} seconds");
}
}
//This is a quick test for "ShouldCommit"
public static void AssertShouldCommit()
{
var smallBatch = new CommitBatchPolicy(10);
var bigBatch = new CommitBatchPolicy(1000);
var reloadPositionCatchedUp = new ProjectionPosition(444, 440, 444);
var rebuildFirstPositionCatchedUp = new ProjectionPosition(444, null, 444);
var reloadCatchingUp900Uncomitted = new ProjectionPosition(999, 99, 8747235);
if (smallBatch.ShouldCommit(reloadPositionCatchedUp) == false)
{
throw new InvalidOperationException("failed expectation: small batch to commit on " + nameof(reloadPositionCatchedUp));
}
if (bigBatch.ShouldCommit(reloadPositionCatchedUp) == false)
{
throw new InvalidOperationException("failed expectation: big batch to commit on " + nameof(reloadPositionCatchedUp));
}
if (smallBatch.ShouldCommit(rebuildFirstPositionCatchedUp) == false)
{
throw new InvalidOperationException("failed expectation: small batch to commit on " + nameof(rebuildFirstPositionCatchedUp));
}
if (smallBatch.ShouldCommit(rebuildFirstPositionCatchedUp) == false)
{
throw new InvalidOperationException("failed expectation: big batch to commit on " + nameof(rebuildFirstPositionCatchedUp));
}
if (smallBatch.ShouldCommit(reloadCatchingUp900Uncomitted) == false)
{
throw new InvalidOperationException("failed expectation: small batch to commit on " + nameof(reloadCatchingUp900Uncomitted));
}
if (bigBatch.ShouldCommit(reloadCatchingUp900Uncomitted))
{
throw new InvalidOperationException("failed expectation: big batch not to commit on " + nameof(reloadCatchingUp900Uncomitted));
}
}
private async Task OnEvent(IAllStreamSubscription subscription, StreamMessage msg,
CancellationToken cancelToken)
{
_lastReadPosition = msg.Position;
try
{
var @event = await Deserialization.Deserialize(msg);
var change = _projection.Apply(@event);
if (change != string.Empty)
{
_dmlCollector.AppendLine(change);
}
await CommitIfRelevant(ProjectionPosition.From(subscription, msg, _lastCommitPosition));
}
catch (Exception e)
{
Console.ForegroundColor = ConsoleColor.Red;
Console.WriteLine($"WHOOPS: {e}");
}
}
//public readonly int EventsPerCommitWhenInputBuffered;
//^-- callbacks for "onCatchupStatus" are dispatched as soon as the latest event in
//the inputstream has been buffered, this is an "almost there"-state
public bool ShouldCommit(ProjectionPosition p)
{
return(p.LooksLikeLatestAvailableInput() || p.UncommitedLength >= EventsPerCommitWhenCatchingUp);
}