// TODO(tschottdorf): this method is somewhat awkward but unless we want to
// give this error back to the client, our options are limited. We'll have to
// run the whole thing for them, or any restart will still end up at the client
// which will not be prepared to be handed a Txn.
func (tc *TxnCoordSender) resendWithTxn(ba roachpb.BatchRequest) (*roachpb.BatchResponse, *roachpb.Error) {
	// Run a one-off transaction with that single command.
	if log.V(1) {
		log.Infof("%s: auto-wrapping in txn and re-executing: ", ba)
	}
	tmpDB := client.NewDBWithPriority(tc, ba.UserPriority)
	var br *roachpb.BatchResponse
	pErr := tmpDB.Txn(func(txn *client.Txn) *roachpb.Error {
		txn.SetDebugName("auto-wrap", 0)
		b := txn.NewBatch()
		b.MaxScanResults = ba.MaxScanResults
		for _, arg := range ba.Requests {
			req := arg.GetInner()
			b.InternalAddRequest(req)
		}
		var pErr *roachpb.Error
		br, pErr = txn.CommitInBatchWithResponse(b)
		return pErr
	})
	if pErr != nil {
		return nil, pErr
	}
	br.Txn = nil // hide the evidence
	return br, nil
}

// createTestNotifyClient creates a new client which connects using an HTTP
// sender to the server at addr. It contains a waitgroup to allow waiting.
func createTestNotifyClient(stopper *stop.Stopper, addr string, priority roachpb.UserPriority) (*client.DB, *notifyingSender) {
	db, err := client.Open(stopper, fmt.Sprintf("rpcs://%[email protected]%s?certs=%s",
		security.NodeUser,
		addr,
		security.EmbeddedCertsDir))
	if err != nil {
		log.Fatal(err)
	}

	sender := &notifyingSender{wrapped: db.GetSender()}
	return client.NewDBWithPriority(sender, priority), sender
}

// TODO(tschottdorf): this method is somewhat awkward but unless we want to
// give this error back to the client, our options are limited. We'll have to
// run the whole thing for them, or any restart will still end up at the client
// which will not be prepared to be handed a Txn.
func (tc *TxnCoordSender) resendWithTxn(ba proto.BatchRequest) (*proto.BatchResponse, error) {
	// Run a one-off transaction with that single command.
	if log.V(1) {
		log.Infof("%s: auto-wrapping in txn and re-executing: ", ba)
	}
	tmpDB := client.NewDBWithPriority(tc, ba.GetUserPriority())
	br := &proto.BatchResponse{}
	if err := tmpDB.Txn(func(txn *client.Txn) error {
		txn.SetDebugName("auto-wrap", 0)
		b := &client.Batch{}
		for _, arg := range ba.Requests {
			req := arg.GetValue().(proto.Request)
			call := proto.Call{Args: req, Reply: req.CreateReply()}
			b.InternalAddCall(call)
			br.Add(call.Reply)
		}
		return txn.CommitInBatch(b)
	}); err != nil {
		return nil, err
	}
	return br, nil
}

// TODO(tschottdorf): this method is somewhat awkward but unless we want to
// give this error back to the client, our options are limited. We'll have to
// run the whole thing for them, or any restart will still end up at the client
// which will not be prepared to be handed a Txn.
func (tc *TxnCoordSender) resendWithTxn(ba proto.BatchRequest) (*proto.BatchResponse, *proto.Error) {
	// Run a one-off transaction with that single command.
	if log.V(1) {
		log.Infof("%s: auto-wrapping in txn and re-executing: ", ba)
	}
	tmpDB := client.NewDBWithPriority(tc, ba.GetUserPriority())
	var br *proto.BatchResponse
	err := tmpDB.Txn(func(txn *client.Txn) error {
		txn.SetDebugName("auto-wrap", 0)
		b := &client.Batch{}
		for _, arg := range ba.Requests {
			req := arg.GetInner()
			b.InternalAddRequest(req)
		}
		var err error
		br, err = txn.CommitInBatchWithResponse(b)
		return err
	})
	if err != nil {
		return nil, proto.NewError(err)
	}
	br.Txn = nil // hide the evidence
	return br, nil
}

// createTestNotifyClient creates a new client which connects using an HTTP
// sender to the server at addr. It contains a waitgroup to allow waiting.
func createTestNotifyClient(t *testing.T, stopper *stop.Stopper, addr string, priority roachpb.UserPriority) (*client.DB, *notifyingSender) {
	db := createTestClient(t, stopper, addr)
	sender := &notifyingSender{wrapped: db.GetSender()}
	return client.NewDBWithPriority(sender, priority), sender
}

//.........这里部分代码省略.........
		// If this transactional command leaves transactional intents, add the key
		// or key range to the intents map. If the transaction metadata doesn't yet
		// exist, create it.
		if call.Reply.Header().GoError() == nil {
			if proto.IsTransactionWrite(call.Args) {
				if txnMeta == nil {
					txn.Writing = true
					trace.Event("coordinator spawns")
					txnMeta = &txnMetadata{
						txn:              *txn,
						keys:             cache.NewIntervalCache(cache.Config{Policy: cache.CacheNone}),
						firstUpdateNanos: tc.clock.PhysicalNow(),
						lastUpdateNanos:  tc.clock.PhysicalNow(),
						timeoutDuration:  tc.clientTimeout,
						txnEnd:           make(chan struct{}),
					}
					tc.txns[id] = txnMeta
					if !tc.stopper.RunAsyncTask(func() {
						tc.heartbeatLoop(id)
					}) {
						// The system is already draining and we can't start the
						// heartbeat. We refuse new transactions for now because
						// they're likely not going to have all intents committed.
						// In principle, we can relax this as needed though.
						call.Reply.Header().SetGoError(&proto.NodeUnavailableError{})
						tc.Unlock()
						tc.unregisterTxn(id)
						return
					}
				}
				txnMeta.addKeyRange(header.Key, header.EndKey)
			}
			// Update our record of this transaction.
			if txnMeta != nil {
				txnMeta.txn = *txn
				txnMeta.setLastUpdate(tc.clock.PhysicalNow())
			}
		}
		tc.Unlock()
	}

	// Cleanup intents and transaction map if end of transaction.
	switch t := call.Reply.Header().GoError().(type) {
	case *proto.TransactionStatusError:
		// Likely already committed or more obscure errors such as epoch or
		// timestamp regressions; consider it dead.
		tc.cleanupTxn(trace, t.Txn)
	case *proto.TransactionAbortedError:
		// If already aborted, cleanup the txn on this TxnCoordSender.
		tc.cleanupTxn(trace, t.Txn)
	case *proto.OpRequiresTxnError:
		// Run a one-off transaction with that single command.
		if log.V(1) {
			log.Infof("%s: auto-wrapping in txn and re-executing", call.Method())
		}
		// TODO(tschottdorf): this part is awkward. Consider resending here
		// without starting a new call, which is hard to trace. Plus, the
		// below depends on default configuration.
		tmpDB := client.NewDBWithPriority(tc, call.Args.Header().GetUserPriority())
		call.Reply.Reset()
		if err := tmpDB.Txn(func(txn *client.Txn) error {
			txn.SetDebugName("auto-wrap", 0)
			b := &client.Batch{}
			b.InternalAddCall(call)
			return txn.CommitInBatch(b)
		}); err != nil {
			log.Warning(err)
		}
	case nil:
		if txn := call.Reply.Header().Txn; txn != nil {
			if _, ok := call.Args.(*proto.EndTransactionRequest); ok {
				// If the --linearizable flag is set, we want to make sure that
				// all the clocks in the system are past the commit timestamp
				// of the transaction. This is guaranteed if either
				// - the commit timestamp is MaxOffset behind startNS
				// - MaxOffset ns were spent in this function
				// when returning to the client. Below we choose the option
				// that involves less waiting, which is likely the first one
				// unless a transaction commits with an odd timestamp.
				if tsNS := txn.Timestamp.WallTime; startNS > tsNS {
					startNS = tsNS
				}
				sleepNS := tc.clock.MaxOffset() -
					time.Duration(tc.clock.PhysicalNow()-startNS)
				if tc.linearizable && sleepNS > 0 {
					defer func() {
						if log.V(1) {
							log.Infof("%v: waiting %s on EndTransaction for linearizability", txn.Short(), util.TruncateDuration(sleepNS, time.Millisecond))
						}
						time.Sleep(sleepNS)
					}()
				}
				if txn.Status != proto.PENDING {
					tc.cleanupTxn(trace, *txn)
				}

			}
		}
	}
}