internal static ActiveTxnRecord GetOldestRecord(TxnContext upTo)
{
var context = TxnContext.Head;
ActiveTxnRecord oldestRecord = null;
TxnContext prevContext = null;
while (context != upTo)
{
var contextOldest = context.OldestRequiredRecord;
if (oldestRecord == null || (contextOldest != null && oldestRecord.TxNumber > contextOldest.TxNumber))
{
oldestRecord = contextOldest;
}
if (!context.OwningThread.IsAlive && prevContext != null)
{
prevContext.Next = context.Next;
}
prevContext = context;
context = context.Next;
}
return(oldestRecord);
}
private void EnsureCommitStatus()
{
ActiveTxnRecord recToCommit = ActiveTxnRecord.LastCommitted.Next;
while (recToCommit != null && recToCommit.TxNumber <= _commitTxnRecord.TxNumber)
{
if (!recToCommit.IsCommited)
{
var writeMap = recToCommit.WriteMap;
writeMap.HelpWriteBack(recToCommit.TxNumber);
ActiveTxnRecord.FinishCommit(recToCommit);
}
recToCommit = recToCommit.Next;
}
/*
* while (ActiveTxnRecord.First.Next != _commitTxnRecord)
* {
*
* }
*
* foreach (var kvpair in WriteMap)
* {
* kvpair.Key.Install(kvpair.Value, _commitTxnRecord.TxNumber);
* }
* ActiveTxnRecord.FinishCommit(_commitTxnRecord);*/
}
private JVTransaction(TransactionStatus status, ActiveTxnRecord txnRecord, JVTransaction parent, ReadMap readMap, WriteMap writeMap)
{
Number = txnRecord.TxNumber;
Parent = parent;
ReadMap = readMap;
WriteMap = writeMap;
Status = status;
_txnRecord = txnRecord;
//Commutes = new List<BaseCommute>();
}
private ActiveTxnRecord Validate(ActiveTxnRecord record)
{
var next = record.Next;
if (next != null)
{
return(ValidateInternal(next));
}
return(record);
}
public void ValidateCommitAndEnqueue()
{
ActiveTxnRecord lastValid = _txnRecord;
do
{
lastValid = Validate(lastValid);
_commitTxnRecord = new ActiveTxnRecord(lastValid.TxNumber + 1,
this.WriteMap);
} while (!lastValid.TrySetNext(_commitTxnRecord));
}
private ActiveTxnRecord ValidateInternal(ActiveTxnRecord record)
{
var valid = record.WriteMap.Validate(this.ReadMap);
if (!valid)
{
throw new STMCommitException();
}
var next = record.Next;
if (next != null)
{
return(ValidateInternal(next));
}
return(record);
}
public static void StartGC()
{
if (!GC_Status)
{
GC_Status = true;
var gc_thread = new Thread(() =>
{
while (GC_Status)
{
var rec = FindOldestRecordInUse();
lasCleanedTo = CleanUpTo(rec, lasCleanedTo);
ActiveTxnRecord.First = null;
Thread.Sleep(2);
}
});
gc_thread.IsBackground = true;
gc_thread.Start();
}
}
internal static ActiveTxnRecord CleanUpTo(ActiveTxnRecord cleanTo, ActiveTxnRecord lastCleanTo)
{
if (cleanTo.TxNumber < lastCleanTo.TxNumber)
{
return(lastCleanTo);
}
var rec = lastCleanTo;
while (rec != cleanTo)
{
rec.Clean();
if (!rec.Next.IsCommited)
{
break;
}
rec = rec.Next;
}
return(rec);
}
internal static void InsertNewRecord(ActiveTxnRecord record)
{
LastCommitted.Next = record;
LastCommitted = record;
}
internal static void FinishCommit(ActiveTxnRecord recToCommit)
{
recToCommit.SetCommitted();
LastCommitted = recToCommit;
}
internal bool TrySetNext(ActiveTxnRecord record)
{
return(Interlocked.CompareExchange <ActiveTxnRecord>(ref this.Next, record, null) == null);
}
public static JVTransaction Start()
{
return(new JVTransaction(ActiveTxnRecord.StartTransaction()));
//return new JVTransaction(_lastCommitted);
}
private JVTransaction()
: this(TransactionStatus.Active, ActiveTxnRecord.StartTransaction(), null, new ReadMap(), new WriteMap())
{
}
private JVTransaction(ActiveTxnRecord txnRecord) : this(TransactionStatus.Active, txnRecord, null, new ReadMap(), new WriteMap())
{
}
public bool Commit()
{
return(CommitLockFree());
if (WriteMap.Count == 0)
{
Status = TransactionStatus.Committed;
//_txnRecord.FinishTransaction();
return(true);
}
bool result;
ActiveTxnRecord commitRecord = null;
lock (CommitLock)
{
var newNumber = ActiveTxnRecord.LastCommitted.TxNumber + 1;
var valid = ReadMap.Validate();
if (!valid)
{
result = false;
}
else
{
if (IsNested)
{
Parent.ReadMap.Merge(ReadMap);
Parent.WriteMap.Merge(WriteMap);
}
else
{
//var bodies = new BaseVBoxBody[WriteMap.Count];
var i = 0;
foreach (var kvpair in WriteMap)
{
//bodies[i] = kvpair.Key.Install(kvpair.Value, newNumber);
kvpair.Key.Install(kvpair.Value, newNumber);
i++;
}
//commitRecord = new ActiveTxnRecord(newNumber, bodies);
commitRecord = new ActiveTxnRecord(newNumber);
ActiveTxnRecord.InsertNewRecord(commitRecord);
}
Status = TransactionStatus.Committed;
result = true;
}
}
/*
* if (result && !IsNested)
* {
* _txnRecord.FinishTransaction();
*
* if (commitRecord != null)
* {
* Interlocked.Decrement(ref commitRecord.Running);
* }
* }*/
return(result);;
}
