public IReadSession OpenReadSession()
{
var anchor = storageEngine.GetCurrentAnchor();
statistics.IncrementReadSessionsOpened();
lock (readSnapshotLock)
{
var documents = new DocumentSet(anchor);
if (lastReadSnapshot != null && lastReadSnapshot.Anchor.Id == anchor.Id)
{
statistics.IncrementSnapshotReuse();
return new ReadSession(anchor, lastReadSnapshot, DisposeReadSession);
}
statistics.IncrementSnapshotRebuild();
if (lastReadSnapshot != null)
{
documents.InitializeFrom(lastReadSnapshot);
}
var visited = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
var visitor = new LoadEverythingVisitor(documents, encoders, visited);
storageEngine.Visit(anchor, visitor);
lastReadSnapshot = documents;
if (lastReadSnapshot != null)
{
documents.RemoveExcept(visited);
}
return new ReadSession(anchor, documents, DisposeReadSession);
}
}