private void FindRecoveryInfo(long requestedVersion, out HybridLogCheckpointInfo recoveredHlcInfo,
out IndexCheckpointInfo recoveredICInfo)
{
Debug.WriteLine("********* Primary Recovery Information ********");
HybridLogCheckpointInfo current, closest = default;
Guid closestToken = default;
long closestVersion = long.MaxValue;
byte[] cookie = default;
// Traverse through all current tokens to find either the largest version or the version that's closest to
// but smaller than the requested version. Need to iterate through all unpruned versions because file system
// is not guaranteed to return tokens in order of freshness.
foreach (var hybridLogToken in checkpointManager.GetLogCheckpointTokens())
{
try
{
current = new HybridLogCheckpointInfo();
current.Recover(hybridLogToken, checkpointManager, hlog.LogPageSizeBits,
out var currCookie, false);
var distanceToTarget = (requestedVersion == -1 ? long.MaxValue : requestedVersion) - current.info.version;
// This is larger than intended version, cannot recover to this.
if (distanceToTarget < 0)
{
continue;
}
// We have found the exact version to recover to --- the above conditional establishes that the
// checkpointed version is <= requested version, and if next version is larger than requestedVersion,
// there cannot be any closer version.
if (current.info.nextVersion > requestedVersion)
{
closest = current;
closestToken = hybridLogToken;
cookie = currCookie;
break;
}
// Otherwise, write it down and wait to see if there's a closer one;
if (distanceToTarget < closestVersion)
{
closestVersion = distanceToTarget;
closest.Dispose();
closest = current;
closestToken = hybridLogToken;
cookie = currCookie;
}
else
{
current.Dispose();
}
}
catch
{
continue;
}
Debug.WriteLine("HybridLog Checkpoint: {0}", hybridLogToken);
}
recoveredHlcInfo = closest;
recoveredCommitCookie = cookie;
if (recoveredHlcInfo.IsDefault())
{
throw new FasterException("Unable to find valid HybridLog token");
}
if (recoveredHlcInfo.deltaLog != null)
{
recoveredHlcInfo.Dispose();
// need to actually scan delta log now
recoveredHlcInfo.Recover(closestToken, checkpointManager, hlog.LogPageSizeBits, out _, true);
}
recoveredHlcInfo.info.DebugPrint();
recoveredICInfo = default;
foreach (var indexToken in checkpointManager.GetIndexCheckpointTokens())
{
try
{
// Recovery appropriate context information
recoveredICInfo = new IndexCheckpointInfo();
recoveredICInfo.Recover(indexToken, checkpointManager);
}
catch
{
continue;
}
if (!IsCompatible(recoveredICInfo.info, recoveredHlcInfo.info))
{
recoveredICInfo = default;
continue;
}
Debug.WriteLine("Index Checkpoint: {0}", indexToken);
recoveredICInfo.info.DebugPrint();
break;
}
if (recoveredICInfo.IsDefault())
{
Debug.WriteLine("No index checkpoint found, recovering from beginning of log");
}
}