Golang BatchRequest.GetUserPriority方法代碼示例

// maybeBeginTxn begins a new transaction if a txn has been specified
// in the request but has a nil ID. The new transaction is initialized
// using the name and isolation in the otherwise uninitialized txn.
// The Priority, if non-zero is used as a minimum.
func (tc *TxnCoordSender) maybeBeginTxn(ba *roachpb.BatchRequest) {
	if ba.Txn == nil {
		return
	}
	if len(ba.Requests) == 0 {
		panic("empty batch with txn")
	}
	if len(ba.Txn.ID) == 0 {
		// TODO(tschottdorf): should really choose the first txn write here.
		firstKey := ba.Requests[0].GetInner().Header().Key
		newTxn := roachpb.NewTransaction(ba.Txn.Name, keys.KeyAddress(firstKey), ba.GetUserPriority(),
			ba.Txn.Isolation, tc.clock.Now(), tc.clock.MaxOffset().Nanoseconds())
		// Use existing priority as a minimum. This is used on transaction
		// aborts to ratchet priority when creating successor transaction.
		if newTxn.Priority < ba.Txn.Priority {
			newTxn.Priority = ba.Txn.Priority
		}
		ba.Txn = newTxn
	}
}

// maybeBeginTxn begins a new transaction if a txn has been specified
// in the request but has a nil ID. The new transaction is initialized
// using the name and isolation in the otherwise uninitialized txn.
// The Priority, if non-zero is used as a minimum.
//
// No transactional writes are allowed unless preceded by a begin
// transaction request within the same batch. The exception is if the
// transaction is already in state txn.Writing=true.
func (tc *TxnCoordSender) maybeBeginTxn(ba *roachpb.BatchRequest) error {
	if ba.Txn == nil {
		return nil
	}
	if len(ba.Requests) == 0 {
		return util.Errorf("empty batch with txn")
	}
	if len(ba.Txn.ID) == 0 {
		// Create transaction without a key. The key is set when a begin
		// transaction request is received.
		newTxn := roachpb.NewTransaction(ba.Txn.Name, nil, ba.GetUserPriority(),
			ba.Txn.Isolation, tc.clock.Now(), tc.clock.MaxOffset().Nanoseconds())
		// Use existing priority as a minimum. This is used on transaction
		// aborts to ratchet priority when creating successor transaction.
		if newTxn.Priority < ba.Txn.Priority {
			newTxn.Priority = ba.Txn.Priority
		}
		ba.Txn = newTxn
	}

	// Check for a begin transaction to set txn key based on the key of
	// the first transactional write. Also enforce that no transactional
	// writes occur before a begin transaction.
	var haveBeginTxn bool
	for _, req := range ba.Requests {
		args := req.GetInner()
		if bt, ok := args.(*roachpb.BeginTransactionRequest); ok {
			if haveBeginTxn || ba.Txn.Writing {
				return util.Errorf("begin transaction requested twice in the same transaction")
			}
			haveBeginTxn = true
			ba.Txn.Key = bt.Key
		}
		if roachpb.IsTransactionWrite(args) && !haveBeginTxn && !ba.Txn.Writing {
			return util.Errorf("transactional write before begin transaction")
		}
	}
	return 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 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.GetUserPriority())
	var br *roachpb.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, roachpb.NewError(err)
	}
	br.Txn = nil // hide the evidence
	return br, nil
}

// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(ctx context.Context, ba roachpb.BatchRequest, br *roachpb.BatchResponse, pErr *roachpb.Error) *roachpb.Error {
	trace := tracer.FromCtx(ctx)
	newTxn := &roachpb.Transaction{}
	newTxn.Update(ba.GetTxn())
	// TODO(tamird): remove this clone. It's currently needed to avoid race conditions.
	pErr = proto.Clone(pErr).(*roachpb.Error)
	err := pErr.GoError()
	// TODO(bdarnell): We're writing to errors here (and where using ErrorWithIndex);
	// since there's no concept of ownership copy-on-write is always preferable.
	switch t := err.(type) {
	case nil:
		newTxn.Update(br.Txn)
		// Move txn timestamp forward to response timestamp if applicable.
		// TODO(tschottdorf): see (*Replica).executeBatch and comments within.
		// Looks like this isn't necessary any more, nor did it prevent a bug
		// referenced in a TODO there.
		newTxn.Timestamp.Forward(br.Timestamp)
	case *roachpb.TransactionStatusError:
		// Likely already committed or more obscure errors such as epoch or
		// timestamp regressions; consider txn dead.
		defer tc.cleanupTxn(trace, t.Txn)
	case *roachpb.OpRequiresTxnError:
		panic("OpRequiresTxnError must not happen at this level")
	case *roachpb.ReadWithinUncertaintyIntervalError:
		// Mark the host as certain. See the protobuf comment for
		// Transaction.CertainNodes for details.
		if t.NodeID == 0 {
			panic("no replica set in header on uncertainty restart")
		}
		newTxn.Update(&t.Txn)
		newTxn.CertainNodes.Add(t.NodeID)
		// If the reader encountered a newer write within the uncertainty
		// interval, move the timestamp forward, just past that write or
		// up to MaxTimestamp, whichever comes first.
		candidateTS := newTxn.MaxTimestamp
		candidateTS.Backward(t.ExistingTimestamp.Add(0, 1))
		newTxn.Timestamp.Forward(candidateTS)
		newTxn.Restart(ba.GetUserPriority(), newTxn.Priority, newTxn.Timestamp)
		t.Txn = *newTxn
	case *roachpb.TransactionAbortedError:
		trace.SetError()
		newTxn.Update(&t.Txn)
		// Increase timestamp if applicable.
		newTxn.Timestamp.Forward(t.Txn.Timestamp)
		newTxn.Priority = t.Txn.Priority
		t.Txn = *newTxn
		// Clean up the freshly aborted transaction in defer(), avoiding a
		// race with the state update below.
		defer tc.cleanupTxn(trace, t.Txn)
	case *roachpb.TransactionPushError:
		newTxn.Update(t.Txn)
		// Increase timestamp if applicable, ensuring that we're
		// just ahead of the pushee.
		newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp.Add(0, 1))
		newTxn.Restart(ba.GetUserPriority(), t.PusheeTxn.Priority-1, newTxn.Timestamp)
		t.Txn = newTxn
	case *roachpb.TransactionRetryError:
		newTxn.Update(&t.Txn)
		newTxn.Restart(ba.GetUserPriority(), t.Txn.Priority, newTxn.Timestamp)
		t.Txn = *newTxn
	case roachpb.TransactionRestartError:
		// Assertion: The above cases should exhaust all ErrorDetails which
		// carry a Transaction.
		if pErr.Detail != nil {
			panic(fmt.Sprintf("unhandled TransactionRestartError %T", err))
		}
	default:
		trace.SetError()
	}

	return func() *roachpb.Error {
		if len(newTxn.ID) <= 0 {
			return pErr
		}
		id := string(newTxn.ID)
		tc.Lock()
		defer tc.Unlock()
		txnMeta := tc.txns[id]
		// For successful transactional requests, keep the written intents and
		// the updated transaction record to be sent along with the reply.
		// The transaction metadata is created with the first writing operation.
		// A tricky edge case is that of a transaction which "fails" on the
		// first writing request, but actually manages to write some intents
		// (for example, due to being multi-range). In this case, there will
		// be an error, but the transaction will be marked as Writing and the
		// coordinator must track the state, for the client's retry will be
		// performed with a Writing transaction which the coordinator rejects
		// unless it is tracking it (on top of it making sense to track it;
		// after all, it **has** laid down intents and only the coordinator
		// can augment a potential EndTransaction call).
		// consider re-using those.
		if intents := ba.GetIntents(); len(intents) > 0 && (err == nil || newTxn.Writing) {
			if txnMeta == nil {
				if !newTxn.Writing {
					panic("txn with intents marked as non-writing")
				}
//.........這裏部分代碼省略.........

// updateState updates the transaction state in both the success and
// error cases, applying those updates to the corresponding txnMeta
// object when adequate. It also updates certain errors with the
// updated transaction for use by client restarts.
func (tc *TxnCoordSender) updateState(ctx context.Context, ba roachpb.BatchRequest, br *roachpb.BatchResponse, pErr *roachpb.Error) *roachpb.Error {
	trace := tracer.FromCtx(ctx)
	newTxn := &roachpb.Transaction{}
	newTxn.Update(ba.GetTxn())
	err := pErr.GoError()
	switch t := err.(type) {
	case nil:
		newTxn.Update(br.GetTxn())
		// Move txn timestamp forward to response timestamp if applicable.
		// TODO(tschottdorf): see (*Replica).executeBatch and comments within.
		// Looks like this isn't necessary any more, nor did it prevent a bug
		// referenced in a TODO there.
		newTxn.Timestamp.Forward(br.Timestamp)
	case *roachpb.TransactionStatusError:
		// Likely already committed or more obscure errors such as epoch or
		// timestamp regressions; consider txn dead.
		defer tc.cleanupTxn(trace, t.Txn)
	case *roachpb.OpRequiresTxnError:
		// TODO(tschottdorf): range-spanning autowrap currently broken.
		panic("TODO(tschottdorf): disabled")
	case *roachpb.ReadWithinUncertaintyIntervalError:
		// Mark the host as certain. See the protobuf comment for
		// Transaction.CertainNodes for details.
		if t.NodeID == 0 {
			panic("no replica set in header on uncertainty restart")
		}
		newTxn.CertainNodes.Add(t.NodeID)
		// If the reader encountered a newer write within the uncertainty
		// interval, move the timestamp forward, just past that write or
		// up to MaxTimestamp, whichever comes first.
		candidateTS := newTxn.MaxTimestamp
		candidateTS.Backward(t.ExistingTimestamp.Add(0, 1))
		newTxn.Timestamp.Forward(candidateTS)
		newTxn.Restart(ba.GetUserPriority(), newTxn.Priority, newTxn.Timestamp)
		t.Txn = *newTxn
	case *roachpb.TransactionAbortedError:
		// Increase timestamp if applicable.
		newTxn.Timestamp.Forward(t.Txn.Timestamp)
		newTxn.Priority = t.Txn.Priority
		t.Txn = *newTxn
		// Clean up the freshly aborted transaction in defer(), avoiding a
		// race with the state update below.
		defer tc.cleanupTxn(trace, t.Txn)
	case *roachpb.TransactionPushError:
		// Increase timestamp if applicable, ensuring that we're
		// just ahead of the pushee.
		newTxn.Timestamp.Forward(t.PusheeTxn.Timestamp.Add(0, 1))
		newTxn.Restart(ba.GetUserPriority(), t.PusheeTxn.Priority-1, newTxn.Timestamp)
		t.Txn = newTxn
	case *roachpb.TransactionRetryError:
		// Increase timestamp if applicable.
		newTxn.Timestamp.Forward(t.Txn.Timestamp)
		newTxn.Restart(ba.GetUserPriority(), t.Txn.Priority, newTxn.Timestamp)
		t.Txn = *newTxn
	case roachpb.TransactionRestartError:
		// Assertion: The above cases should exhaust all ErrorDetails which
		// carry a Transaction.
		if pErr.Detail != nil {
			panic(fmt.Sprintf("unhandled TransactionRestartError %T", err))
		}
	}

	return func() *roachpb.Error {
		if len(newTxn.ID) <= 0 {
			return pErr
		}
		id := string(newTxn.ID)
		tc.Lock()
		defer tc.Unlock()
		txnMeta := tc.txns[id]
		// For successful transactional requests, keep the written intents and
		// the updated transaction record to be sent along with the reply.
		// The transaction metadata is created with the first writing operation
		// TODO(tschottdorf): already computed the intents prior to sending,
		// consider re-using those.
		if intents := ba.GetIntents(); len(intents) > 0 && err == nil {
			if txnMeta == nil {
				newTxn.Writing = true
				txnMeta = &txnMetadata{
					txn:              *newTxn,
					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 the transaction is already over, there's no point in
				// launching a one-off coordinator which will shut down right
				// away.
				if _, isEnding := ba.GetArg(roachpb.EndTransaction); !isEnding {
					trace.Event("coordinator spawns")
					if !tc.stopper.RunAsyncTask(func() {
						tc.heartbeatLoop(id)
					}) {
						// The system is already draining and we can't start the
//.........這裏部分代碼省略.........