private void SnapshotAndTruncateLog(long to, ManualResetEventSlim allowFurtherModifications)
{
var task = new Task(() =>
{
OnSnapshotCreationStarted();
try
{
var currentTerm = PersistentState.CurrentTerm;
_log.Info("Starting to create snapshot up to {0} in term {1}", to, currentTerm);
StateMachine.CreateSnapshot(to, currentTerm, allowFurtherModifications);
PersistentState.MarkSnapshotFor(to, currentTerm,
Options.MaxLogLengthBeforeCompaction - (Options.MaxLogLengthBeforeCompaction / 8));
_log.Info("Finished creating snapshot for {0} in term {1}", to, currentTerm);
OnSnapshotCreationEnded();
}
catch (Exception e)
{
_log.Error("Failed to create snapshot", e);
OnSnapshotCreationError(e);
}
finally
{
Interlocked.Exchange(ref _snapshottingTask, null);
}
});
if (Interlocked.CompareExchange(ref _snapshottingTask, task, null) != null)
{
allowFurtherModifications.Set();
return;
}
task.Start();
}
public void CanProperlySnapshot()
{
using (var state = new PersistentState("self", StorageEnvironmentOptions.CreateMemoryOnly(), CancellationToken.None)
{
CommandSerializer = new JsonCommandSerializer()
})
{
state.UpdateTermTo(null, 1);
state.AppendToLeaderLog(new NopCommand());
for (int i = 0; i < 5; i++)
{
state.AppendToLeaderLog(new DictionaryCommand.Set
{
Key = i.ToString(),
Value = i
});
}
state.MarkSnapshotFor(6, 1, 5);
state.AppendToLeaderLog(new DictionaryCommand.Set
{
Key = "1",
Value = 4
});
var lastLogEntry = state.LastLogEntry();
Assert.Equal(7, lastLogEntry.Index);
}
}