// Batch sends a request to Cockroach via RPC. Errors which are retryable are
// retried with backoff in a loop using the default retry options. Other errors
// sending the request are retried indefinitely using the same client command
// ID to avoid reporting failure when in fact the command may have gone through
// and been executed successfully. We retry here to eventually get through with
// the same client command ID and be given the cached response.
func (s *rpcSender) Send(ctx context.Context, ba proto.BatchRequest) (*proto.BatchResponse, *proto.Error) {
var err error
var br proto.BatchResponse
for r := retry.Start(s.retryOpts); r.Next(); {
select {
case <-s.client.Healthy():
default:
err = fmt.Errorf("failed to send RPC request %s: client is unhealthy", method)
log.Warning(err)
continue
}
if err = s.client.Call(method, &ba, &br); err != nil {
br.Reset() // don't trust anyone.
// Assume all errors sending request are retryable. The actual
// number of things that could go wrong is vast, but we don't
// want to miss any which should in theory be retried with the
// same client command ID. We log the error here as a warning so
// there's visiblity that this is happening. Some of the errors
// we'll sweep up in this net shouldn't be retried, but we can't
// really know for sure which.
log.Warningf("failed to send RPC request %s: %s", method, err)
continue
}
// On successful post, we're done with retry loop.
break
}
if err != nil {
return nil, proto.NewError(err)
}
pErr := br.Error
br.Error = nil
return &br, pErr
}
// sendBatch unrolls a batched command and sends each constituent
// command in parallel.
// TODO(tschottdorf): modify sendBatch so that it sends truly parallel requests
// when outside of a Transaction. This can then be used to address the TODO in
// (*TxnCoordSender).resolve().
func (tc *TxnCoordSender) sendBatch(ctx context.Context, batchArgs *proto.BatchRequest, batchReply *proto.BatchResponse) {
// Prepare the calls by unrolling the batch. If the batchReply is
// pre-initialized with replies, use those; otherwise create replies
// as needed.
// TODO(spencer): send calls in parallel.
batchReply.Txn = batchArgs.Txn
for i := range batchArgs.Requests {
args := batchArgs.Requests[i].GetValue().(proto.Request)
if err := updateForBatch(args, batchArgs.RequestHeader); err != nil {
batchReply.Header().SetGoError(err)
return
}
call := proto.Call{Args: args}
// Create a reply from the method type and add to batch response.
if i >= len(batchReply.Responses) {
call.Reply = args.CreateReply()
batchReply.Add(call.Reply)
} else {
call.Reply = batchReply.Responses[i].GetValue().(proto.Response)
}
tc.sendOne(ctx, call)
// Amalgamate transaction updates and propagate first error, if applicable.
if batchReply.Txn != nil {
batchReply.Txn.Update(call.Reply.Header().Txn)
}
if call.Reply.Header().Error != nil {
batchReply.Error = call.Reply.Header().Error
return
}
}
}
// sendBatch unrolls a batched command and sends each constituent
// command in parallel.
func (tc *TxnCoordSender) sendBatch(batchArgs *proto.BatchRequest, batchReply *proto.BatchResponse) {
// Prepare the calls by unrolling the batch. If the batchReply is
// pre-initialized with replies, use those; otherwise create replies
// as needed.
// TODO(spencer): send calls in parallel.
batchReply.Txn = batchArgs.Txn
for i := range batchArgs.Requests {
// Initialize args header values where appropriate.
args := batchArgs.Requests[i].GetValue().(proto.Request)
method, err := proto.MethodForRequest(args)
call := &client.Call{Method: method, Args: args}
if err != nil {
batchReply.SetGoError(err)
return
}
if args.Header().User == "" {
args.Header().User = batchArgs.User
}
if args.Header().UserPriority == nil {
args.Header().UserPriority = batchArgs.UserPriority
}
args.Header().Txn = batchArgs.Txn
// Create a reply from the method type and add to batch response.
if i >= len(batchReply.Responses) {
if call.Reply, err = proto.CreateReply(method); err != nil {
batchReply.SetGoError(util.Errorf("unsupported method in batch: %s", method))
return
}
batchReply.Add(call.Reply)
} else {
call.Reply = batchReply.Responses[i].GetValue().(proto.Response)
}
tc.sendOne(call)
// Amalgamate transaction updates and propagate first error, if applicable.
if batchReply.Txn != nil {
batchReply.Txn.Update(call.Reply.Header().Txn)
}
if call.Reply.Header().Error != nil {
batchReply.Error = call.Reply.Header().Error
return
}
}
}
