Golang RequestHeader.Timestamp方法代碼示例

// beginCmd waits for any overlapping, already-executing commands via
// the command queue and adds itself to the queue to gate follow-on
// commands which overlap its key range. This method will block if
// there are any overlapping commands already in the queue. Returns
// the command queue insertion key, to be supplied to subsequent
// invocation of endCmd().
func (r *Range) beginCmd(header *proto.RequestHeader, readOnly bool) interface{} {
	r.Lock()
	var wg sync.WaitGroup
	r.cmdQ.GetWait(header.Key, header.EndKey, readOnly, &wg)
	cmdKey := r.cmdQ.Add(header.Key, header.EndKey, readOnly)
	r.Unlock()
	wg.Wait()
	// Update the incoming timestamp if unset. Wait until after any
	// preceding command(s) for key range are complete so that the node
	// clock has been updated to the high water mark of any commands
	// which might overlap this one in effect.
	if header.Timestamp.Equal(proto.ZeroTimestamp) {
		header.Timestamp = r.rm.Clock().Now()
	}
	return cmdKey
}

//.........這裏部分代碼省略.........
		epoch := -1
		// Start a txn that does read-after-write.
		// The txn will be restarted twice, and the out-of-order put
		// will happen in the second epoch.
		if err := store.DB().Txn(func(txn *client.Txn) error {
			epoch++

			if epoch == 1 {
				// Wait until the second get operation is issued.
				close(waitTxnRestart)
				<-waitSecondGet
			}

			updatedVal := []byte("updatedVal")
			if err := txn.Put(key, updatedVal); err != nil {
				return err
			}

			// Make sure a get will return the value that was just written.
			actual, err := txn.Get(key)
			if err != nil {
				return err
			}
			if !bytes.Equal(actual.ValueBytes(), updatedVal) {
				t.Fatalf("unexpected get result: %s", actual)
			}

			if epoch == 0 {
				// Wait until the first get operation will push the txn timestamp.
				close(waitPut)
				<-waitFirstGet
			}

			b := &client.Batch{}
			err = txn.Commit(b)
			return err
		}); err != nil {
			t.Fatal(err)
		}

		if epoch != 2 {
			t.Fatalf("unexpected number of txn retries: %d", epoch)
		}

		close(waitTxnComplete)
	}()

	<-waitPut

	// Start the Reader.

	// Advance the clock and send a get operation with higher
	// priority to trigger the txn restart.
	manualClock.Increment(100)

	priority := int32(math.MaxInt32)
	requestHeader := proto.RequestHeader{
		Key:          proto.Key(key),
		RaftID:       1,
		Replica:      proto.Replica{StoreID: store.StoreID()},
		UserPriority: &priority,
		Timestamp:    clock.Now(),
	}
	getCall := proto.Call{
		Args: &proto.GetRequest{
			RequestHeader: requestHeader,
		},
		Reply: &proto.GetResponse{},
	}
	err = store.ExecuteCmd(context.Background(), getCall)
	if err != nil {
		t.Fatalf("failed to get: %s", err)
	}

	// Wait until the writer restarts the txn.
	close(waitFirstGet)
	<-waitTxnRestart

	// Advance the clock and send a get operation again. This time
	// we use TestingCommandFilter so that a get operation is not
	// processed after the write intent is resolved (to prevent the
	// timestamp cache from being updated).
	manualClock.Increment(100)

	requestHeader.Timestamp = clock.Now()
	getCall = proto.Call{
		Args: &proto.GetRequest{
			RequestHeader: requestHeader,
		},
		Reply: &proto.GetResponse{},
	}

	err = store.ExecuteCmd(context.Background(), getCall)
	if err == nil {
		t.Fatal("unexpected success of get")
	}

	close(waitSecondGet)
	<-waitTxnComplete
}