/// <summary>
/// Rollback transaction operation - ignore all modified pages and return new pages into disk
/// After rollback, all snapshot are closed
/// </summary>
public void Rollback()
{
ENSURE(_state == TransactionState.Active, $"transaction must be active to rollback (current state: {_state})");
LOG($"rollback transaction ({_transPages.TransactionSize} pages with {_transPages.NewPages.Count} returns)", "TRANSACTION");
// if transaction contains new pages, must return to database in another transaction
if (_transPages.NewPages.Count > 0)
{
this.ReturnNewPages();
}
// dispose all snaphosts
foreach (var snapshot in _snapshots.Values)
{
// but first, if writable, discard changes
if (snapshot.Mode == LockMode.Write)
{
// discard all dirty pages
_disk.DiscardDirtyPages(snapshot.GetWritablePages(true, true).Select(x => x.Buffer));
// discard all clean pages
_disk.DiscardCleanPages(snapshot.GetWritablePages(false, true).Select(x => x.Buffer));
}
// now, release pages
snapshot.Dispose();
}
_state = TransactionState.Aborted;
}
