16 Older versions of a node

Every write appends the whole node to the transaction log, linked to the version before it. So the log is a version history, and FindOlderVersions reads it, newest first:

NodeVersion<IVenue>[] history = db.FindOlderVersions<IVenue>(venueId);               // up to 100
NodeVersion<IVenue>[] recent  = db.FindOlderVersions<IVenue>(venueId, maxCount: 10);

foreach (var v in history) {
    Console.WriteLine($"{v.EstimatedCreationUtc:u}  {v.Node.Name}  capacity {v.Node.Capacity}");
}

Each NodeVersion<T> holds the node as it was (Node) and the time of the write (Timestamp, or EstimatedCreationUtc as a UTC time). The current version is not included.

It reads the log files on every call. Use it for history and audit screens, not on every page view.
How far back it reaches depends on the log. A log rewrite (a backup with TruncateBackups, or AutoTruncate) keeps only the current state. Turn on SecondaryBackupLog (§12.1) to keep a second log that survives rewrites.
Relations are not versioned. The relation properties of a version read the store as it is now.
Deleted nodes have no history, and inserting the same id again starts a new one.

16.1 Reverting the database to an earlier point — The revert API puts the whole database back to an earlier point by permanently deleting every transaction after it. Use it for experiments, tests and seeding, by hand or from a coding agent: try something on real data…