/// <summary>
/// Split a transaction request between multiple shards
/// </summary>
/// <param name="serverSelector">a functions that gives the shard index for a primary key</param>
/// <param name="serverCount">the total number of shards</param>
/// <returns></returns>
public SafeDictionary <int, TransactionRequest> SplitByServer([NotNull] Func <KeyValue, int> serverSelector, int serverCount)
{
if (serverSelector == null)
{
throw new ArgumentNullException(nameof(serverSelector));
}
var result = new SafeDictionary <int, TransactionRequest>(() => new TransactionRequest {
TransactionId = TransactionId
});
foreach (var childRequest in ChildRequests)
{
TransactionRequest transactionRequest;
int shard = 0;
switch (childRequest)
{
// simple put requests contain ore or more items from the same collection and no condition
case PutRequest simplePutRequest when !simplePutRequest.HasCondition:
var byServer = simplePutRequest.SplitByServer(serverSelector);
foreach (var pair in byServer)
{
transactionRequest = result.GetOrCreate(pair.Key);
transactionRequest.ChildRequests.Add(pair.Value);
}
break;
// a put request with a condition. It can contain a single item
case PutRequest conditionalUpdate when conditionalUpdate.HasCondition:
shard = serverSelector(conditionalUpdate.Items.Single().PrimaryKey);
transactionRequest = result.GetOrCreate(shard);
transactionRequest.ChildRequests.Add(conditionalUpdate);
break;
// a simple delete request contains one object to be deleted
case RemoveRequest simpleDeleteRequest:
shard = serverSelector(simpleDeleteRequest.PrimaryKey);
transactionRequest = result.GetOrCreate(shard);
transactionRequest.ChildRequests.Add(simpleDeleteRequest);
break;
// a delete many request contains a predicate that needs to be send to all servers
case RemoveManyRequest deleteMany:
for (int i = 0; i < serverCount; i++)
{
transactionRequest = result.GetOrCreate(i);
transactionRequest.ChildRequests.Add(deleteMany);
}
break;
}
}
return(result);
}
public void AddToSession(Guid sessionId, IList <PackedObject> objects)
{
var list = _objectsBySession.GetOrCreate(sessionId);
lock (list)
{
list.AddRange(objects);
}
}
private ServerSideLock Lock(string name)
{
return(_locksByCollection.GetOrCreate(name));
}
