public void CreateLocalPartitions()
{
List <string> partitions = PartitionMapping.getPartitionsByServerID(serverId);
foreach (string partition_id in partitions)
{
server.createPartition(partition_id);
}
}
private void read(string partition_id, string object_id, string server_id)
{
string result = "N/A";
bool got_result = false;
ReadReply reply;
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
try
{
reply = client.Read(new ReadRequest {
ObjectKey = object_key
});
if (reply.ObjectExists)
{
result = reply.Object.Val;
got_result = true;
}
// server is crashed
} catch
{
handle_crashed_server(attached_server_id);
got_result = false;
}
}
// 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
try
{
reply = client.Read(new ReadRequest {
ObjectKey = object_key
});
if (reply.ObjectExists)
{
result = reply.Object.Val;
got_result = true;
}
// server is crashed
} catch
{
handle_crashed_server(attached_server_id);
got_result = false;
}
}
}
// 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
try
{
reply = client.Read(new ReadRequest {
ObjectKey = object_key
});
if (reply.ObjectExists)
{
result = reply.Object.Val;
got_result = true;
}
// server is crashed
} catch
{
handle_crashed_server(attached_server_id);
got_result = false;
}
}
}
if (got_result == false)
{
result = "N/A";
}
Console.WriteLine("Read Result: " + result);
}
