private bool NotifyPartitionsAboutCrashedServerAndReattachNewMaster(string crashedServerId)
{
List <string> partitions = PartitionMapping.GetPartitionsThatContainServer(crashedServerId);
foreach (string partitionName in partitions)
{
Console.WriteLine(">>> Notify Servers in Partition about Crash...");
Console.WriteLine(">>> Partition=" + partitionName);
string[] partitionNodes = PartitionMapping.GetPartitionAllNodes(partitionName);
bool newMasterWasReattachedSuccessfully = false;
foreach (string serverId in partitionNodes)
{
if (serverId == crashedServerId)
{
continue; // Skip crashed server
}
else if (TryNotifyServerAboutCrashedServer(partitionName, serverId, crashedServerId))
{
newMasterWasReattachedSuccessfully = true;
break;
}
}
return(newMasterWasReattachedSuccessfully);
}
return(false);
}
private void read(string partition_id, string object_id, string server_id)
{
bool got_result = false;
var object_key = new DataStoreKeyDto
{
PartitionId = partition_id,
ObjectId = object_id
};
if (debug_console)
{
Console.WriteLine("Reading from the server...");
}
Console.WriteLine(">>> Read request...");
// if the client is attached to a server and that server contains the desired partition
List <string> available_partitions_in_server = PartitionMapping.GetPartitionsByServerID(attached_server_id);
if (!string.IsNullOrEmpty(attached_server_id) && available_partitions_in_server.Contains(partition_id))
{
if (debug_console)
{
Console.WriteLine("Reading from the Attached Server: " + attached_server_id);
}
// read value from attached server
got_result = TryReadValue(object_key, partition_id);
}
// if theres no result yet and there is a valid server_id parameter
if ((!got_result) && (!server_id.Equals("-1")))
{
// check if the server hint even has the partition
available_partitions_in_server = PartitionMapping.GetPartitionsByServerID(server_id);
if (available_partitions_in_server.Contains(partition_id))
{
if (debug_console)
{
Console.WriteLine("Attach to new Server: " + server_id);
}
reattachServer(server_id);
// read value from alternative server
got_result = TryReadValue(object_key, partition_id);
}
}
// if theres no result yet, the client should find a server serving partition_id on its own
// it will try to connect to every single node in that partition
if (!got_result)
{
string[] partition_nodes = PartitionMapping.GetPartitionAllNodes(partition_id);
foreach (string node_id in partition_nodes)
{
if (debug_console)
{
Console.WriteLine("Attach to new Server: " + node_id);
}
reattachServer(node_id);
// read value from one of the partition servers
got_result = TryReadValue(object_key, partition_id);
}
}
if (got_result == false)
{
Console.WriteLine("Read Result: N/A");
}
}
