internal override void Visit(ReplaceVersionRequest req)
{
VersionEntry verEntry = req.RemoteVerEntry;
if (verEntry == null)
{
Dictionary <long, VersionEntry> versionList = null;
if (!this.dict.TryGetValue(req.RecordKey, out versionList) ||
!versionList.TryGetValue(req.VersionKey, out verEntry))
{
throw new TransactionException("The specified version does not exist.");
}
}
if (verEntry.TxId == req.SenderId && verEntry.EndTimestamp == req.ExpectedEndTs)
{
verEntry.BeginTimestamp = req.BeginTs;
verEntry.EndTimestamp = req.EndTs;
verEntry.TxId = req.TxId;
}
VersionEntry.CopyValue(verEntry, req.LocalVerEntry);
req.Result = req.LocalVerEntry;
req.Finished = true;
}
internal override void Visit(ReplaceVersionRequest req)
{
VersionEntry entry = req.RemoteVerEntry;
if (entry == null)
{
throw new TransactionException("The version entry should be referenced for main-memory k-v.");
}
if (entry.TxId == req.SenderId &&
entry.EndTimestamp == req.ExpectedEndTs &&
entry.VersionKey == req.VersionKey)
{
while (Interlocked.CompareExchange(ref entry.latch, 1, 0) != 0)
{
;
}
entry.BeginTimestamp = req.BeginTs;
entry.EndTimestamp = req.EndTs;
entry.TxId = req.TxId;
VersionEntry.CopyValue(entry, req.LocalVerEntry);
Interlocked.Exchange(ref entry.latch, 0);
}
req.Result = req.LocalVerEntry;
req.Finished = true;
}
internal override void Visit(UpdateVersionMaxCommitTsRequest req)
{
VersionEntry verEntry = req.RemoteVerEntry;
if (verEntry == null)
{
throw new TransactionException("The version entry should be referenced for main-memory k-v.");
}
if (verEntry.VersionKey != req.VersionKey)
{
throw new TransactionException("The referenced version entry has been recycled for new data.");
}
while (Interlocked.CompareExchange(ref verEntry.latch, 1, 0) != 0)
{
;
}
verEntry.MaxCommitTs = Math.Max(req.MaxCommitTs, verEntry.MaxCommitTs);
VersionEntry.CopyValue(verEntry, req.LocalVerEntry);
Interlocked.Exchange(ref verEntry.latch, 0);
req.Result = req.LocalVerEntry;
req.Finished = true;
}
internal override void Visit(GetVersionListRequest req)
{
Dictionary <long, VersionEntry> versionList = null;
if (!this.dict.TryGetValue(req.RecordKey, out versionList))
{
req.RemoteVerList = null;
req.Result = 0;
req.Finished = true;
return;
}
VersionEntry tailPointer = versionList[SingletonDictionaryVersionTable.TAIL_KEY];
long lastVersionKey = tailPointer.BeginTimestamp;
TxList <VersionEntry> localList = req.LocalContainer;
TxList <VersionEntry> remoteList = req.RemoteContainer;
int entryCount = 0;
// Only returns top 2 newest versions. This is enough for serializability.
// For other isolation levels, more versions may need to be returned.
// When old versions may be truncated, it is desirable to maintain a head pointer as well,
// so as to increase the lower bound of version keys and reduce the number of iterations.
while (lastVersionKey >= 0 && entryCount < 2)
{
// To make it run under .Net 4.5
VersionEntry verEntry = null;
versionList.TryGetValue(lastVersionKey, out verEntry);
if (verEntry != null)
{
VersionEntry.CopyValue(verEntry, localList[entryCount]);
remoteList.Add(verEntry);
entryCount++;
if (verEntry.TxId == VersionEntry.EMPTY_TXID)
{
break;
}
}
lastVersionKey--;
}
req.RemoteVerList = versionList;
req.Result = entryCount;
req.Finished = true;
}
internal override void Visit(GetVersionListRequest req)
{
if (!this.dict.TryGetValue(req.RecordKey, out VersionList versionList))
{
req.RemoteVerList = null;
req.Result = 0;
req.Finished = true;
return;
}
TxList <VersionEntry> localList = req.LocalContainer;
TxList <VersionEntry> remoteList = req.RemoteContainer;
int entryCount = 0;
versionList.TryPeek(
out VersionEntry lastVersion,
out VersionEntry secondToLastEntry);
while (Interlocked.CompareExchange(ref lastVersion.latch, 1, 0) != 0)
{
;
}
VersionEntry.CopyValue(lastVersion, localList[entryCount]);
Interlocked.Exchange(ref lastVersion.latch, 0);
// Add a reference to a version entry. No need to take the latch.
remoteList.Add(lastVersion);
entryCount++;
if (lastVersion.TxId != VersionEntry.EMPTY_TXID)
{
while (Interlocked.CompareExchange(ref secondToLastEntry.latch, 1, 0) != 0)
{
;
}
VersionEntry.CopyValue(secondToLastEntry, localList[entryCount]);
Interlocked.Exchange(ref secondToLastEntry.latch, 0);
// Add a reference to a version entry. No need to take the latch.
remoteList.Add(secondToLastEntry);
entryCount++;
}
req.RemoteVerList = versionList;
req.Result = entryCount;
req.Finished = true;
}
internal override void Visit(ReadVersionRequest req)
{
VersionEntry verEntry = req.RemoteVerEntry;
if (verEntry == null)
{
Dictionary <long, VersionEntry> versionList = null;
if (!this.dict.TryGetValue(req.RecordKey, out versionList) ||
!versionList.TryGetValue(req.VersionKey, out verEntry))
{
req.Result = null;
req.Finished = true;
}
}
VersionEntry.CopyValue(verEntry, req.LocalVerEntry);
req.Result = req.LocalVerEntry;
req.Finished = true;
}
internal override void Visit(UpdateVersionMaxCommitTsRequest req)
{
VersionEntry verEntry = req.RemoteVerEntry;
if (verEntry == null)
{
Dictionary <long, VersionEntry> versionList = null;
if (!this.dict.TryGetValue(req.RecordKey, out versionList) ||
!versionList.TryGetValue(req.VersionKey, out verEntry))
{
throw new TransactionException("The specified version does not exist.");
}
}
// Only update the max commit time when uploaded commit time is larger than the version's
verEntry.MaxCommitTs = Math.Max(verEntry.MaxCommitTs, req.MaxCommitTs);
VersionEntry.CopyValue(verEntry, req.LocalVerEntry);
req.Result = req.LocalVerEntry;
req.Finished = true;
}
