/** Fetch a split from remote worker and keep it in the shared memory region
* @param dest a memory pointer where the split will be written (usually shared mem)
* @param name a name of split to fetch
* @param size the size of split to fetch
* @param client a worker information from where we will fetch the split
* @param myhostname a name of worker who initiate the transfer request
* @param store a location other than dram where the split will be written. It can be zero-length
* @return return code from server
*/
int32_t TransferServer::transfer_blob(void *dest, const string &name,
size_t size, WorkerInfo* client,
const string& myhostname,
const string &store) {
// Setup the transfer
this->dest_ = dest;
this->size_ = size;
bytes_fetched_ = 0;
// Initialize semaphore to zero. Server thread will increment
// when it is ready
sem_init(&server_ready, 0, 0);
// Setup a receicing thread.
// Later, we will send a Fetch request,
// and the data will arrive to this thread
pthread_t server_thread;
pthread_create(&server_thread, 0, transfer_pthread, this);
// fprintf(stderr,
// "Waiting for server to be ready for transfer array %s from %s\n",
// a.name.c_str(), a.location.name.c_str());
// Wait till server is ready
sem_wait(&server_ready);
// FIXME(shivaram): This doesn't work on bfc machines
// char hostname[64]; // HOST_NAME_MAX is 64 in Linux
// int ret = gethostname(hostname, 64);
// if (ret < 0) {
// return ret;
// }
// Information of the requester
ServerInfo location;
location.set_name(myhostname);
location.set_presto_port(server_socket_port);
// Create a fetch request
FetchRequest req;
req.mutable_location()->CopyFrom(location);
req.set_size(size);
req.set_name(name);
if (!store.empty()) {
req.set_store(store);
}
client->NewTransfer(req); // request transfer to remote workers
void* server_ret;
pthread_join(server_thread, &server_ret);
sem_destroy(&server_ready);
return *reinterpret_cast<int32_t*>(server_ret);
// TODO(erik): error handling
// } else {
// // Cancel the server thread if transfer failed.
// // TODO(shivaram): Check if this behaves correctly or use signals.
// fprintf(stderr, "Transfer failed, cancelling server\n");
// sem_destroy(&server_ready);
// pthread_cancel(server_thread);
// shutdown(serverfd, SHUT_RDWR);
// close(serverfd);
// return -1;
// }
}
