private LatestVersion ReadVersion(int fileRegisterIndex, Helper.Semantics semantics)
{
Console.WriteLine("READ VERSION " + fileRegisterIndex);
string filename = fileRegister.FilenameAt(fileRegisterIndex);
FileVersion original = fileRegister.FileDataAt(fileRegisterIndex).Version;
FileMetadata fileMetadata = fileRegister.FileMetadataAt(fileRegisterIndex);
// data server id / file data
ConcurrentDictionary <string, FileVersion> reads = new ConcurrentDictionary <string, FileVersion>();
int requests = 0;
LatestVersion quorumVersion = null;
//QUORUM
while (true)
{
// voting
ReadQuorum quorum = new ReadQuorum(fileMetadata.ReadQuorum, semantics);
foreach (var entry in reads)
{
FileVersion vote = entry.Value;
string dataServerId = entry.Key;
quorum.AddVote(vote, dataServerId);
if (quorum.CheckQuorum(vote, original))
{
quorumVersion = new LatestVersion(vote, quorum.DataServersIds(vote));
break;
}
}
// found the quorum file
if (quorumVersion != null)
{
break;
}
// if there are still pending requests
// dont create new ones
if (requests > 0)
{
continue;
}
// if all the votes arrived at the quorum
// stops when all requests are counted (requests = 0)
if (quorum.Count == (requests + quorum.Count))
{
// get possible new fileMetadata locations
// possible optimization
// check if there are no data servers
fileMetadata = OpenFileMetadata(filename);
// broadcast to all dataServers that have that file
foreach (var entry in fileMetadata.Locations)
{
string id = entry.Key;
string location = entry.Value;
string localFilename = fileMetadata.LocalFilenames[id];
// increment right away so it doesn't request untill its decremented
Interlocked.Increment(ref requests);
Thread request = new Thread(() =>
{
IDataServerToClient dataServer = (IDataServerToClient)Activator.GetObject(
typeof(IDataServerToClient),
location);
FileVersion fileVersion = null;
try
{
fileVersion = dataServer.Version(localFilename);
}
catch (ProcessFailedException) { }
catch (ProcessFreezedException) { }
finally
{
reads[id] = fileVersion;
Interlocked.Decrement(ref requests);
}
});
request.Start();
}
}
}
return(quorumVersion);
}
private LatestVersion ReadVersion(int fileRegisterIndex, Helper.Semantics semantics)
{
Console.WriteLine("READ VERSION " + fileRegisterIndex);
string filename = fileRegister.FilenameAt(fileRegisterIndex);
FileVersion original = fileRegister.FileDataAt(fileRegisterIndex).Version;
FileMetadata fileMetadata = fileRegister.FileMetadataAt(fileRegisterIndex);
// data server id / file data
ConcurrentDictionary<string, FileVersion> reads = new ConcurrentDictionary<string, FileVersion>();
int requests = 0;
LatestVersion quorumVersion = null;
//QUORUM
while (true)
{
// voting
ReadQuorum quorum = new ReadQuorum(fileMetadata.ReadQuorum, semantics);
foreach (var entry in reads)
{
FileVersion vote = entry.Value;
string dataServerId = entry.Key;
quorum.AddVote(vote, dataServerId);
if (quorum.CheckQuorum(vote, original))
{
quorumVersion = new LatestVersion(vote, quorum.DataServersIds(vote));
break;
}
}
// found the quorum file
if (quorumVersion != null) break;
// if there are still pending requests
// dont create new ones
if (requests > 0) continue;
// if all the votes arrived at the quorum
// stops when all requests are counted (requests = 0)
if (quorum.Count == (requests + quorum.Count))
{
// get possible new fileMetadata locations
// possible optimization
// check if there are no data servers
fileMetadata = OpenFileMetadata(filename);
// broadcast to all dataServers that have that file
foreach (var entry in fileMetadata.Locations)
{
string id = entry.Key;
string location = entry.Value;
string localFilename = fileMetadata.LocalFilenames[id];
// increment right away so it doesn't request untill its decremented
Interlocked.Increment(ref requests);
Thread request = new Thread(() =>
{
IDataServerToClient dataServer = (IDataServerToClient)Activator.GetObject(
typeof(IDataServerToClient),
location);
FileVersion fileVersion = null;
try
{
fileVersion = dataServer.Version(localFilename);
}
catch (ProcessFailedException) { }
catch (ProcessFreezedException) { }
finally
{
reads[id] = fileVersion;
Interlocked.Decrement(ref requests);
}
});
request.Start();
}
}
}
return quorumVersion;
}
