Golang metrics.ObserveHist函數代碼示例

func (l *L1L2BatchOrca) Prepend(req common.SetRequest) error {
	//log.Println("prepend", string(req.Key))

	metrics.IncCounter(MetricCmdPrependL2)
	start := timer.Now()

	err := l.l2.Prepend(req)

	metrics.ObserveHist(HistPrependL2, timer.Since(start))

	if err != nil {
		// Prepending in L2 did not succeed. Don't try in L1 since this means L2
		// may not have succeeded.
		if err == common.ErrItemNotStored {
			metrics.IncCounter(MetricCmdPrependNotStoredL2)
			metrics.IncCounter(MetricCmdPrependNotStored)
			return err
		}

		metrics.IncCounter(MetricCmdPrependErrorsL2)
		metrics.IncCounter(MetricCmdPrependErrors)
		return err
	}

	// L2 succeeded, so it's time to try L1. If L1 fails with a not found, we're
	// still good since L1 is allowed to not have the data when L2 does. If
	// there's an error, we need to fail because we're not in an unknown state
	// where L1 possibly doesn't have the Prepend when L2 does. We don't recover
	// from this but instead fail the request and let the client retry.
	metrics.IncCounter(MetricCmdPrependL1)
	start = timer.Now()

	err = l.l1.Prepend(req)

	metrics.ObserveHist(HistPrependL1, timer.Since(start))

	if err != nil {
		// Not stored in L1 is still fine. There's a possibility that a
		// concurrent delete happened or that the data has just been pushed out
		// of L1. Prepend will not bring data back into L1 as it's not necessarily
		// going to be immediately read.
		if err == common.ErrItemNotStored || err == common.ErrKeyNotFound {
			metrics.IncCounter(MetricCmdPrependNotStoredL1)
			metrics.IncCounter(MetricCmdPrependStored)
			return l.res.Prepend(req.Opaque, req.Quiet)
		}

		metrics.IncCounter(MetricCmdPrependErrorsL1)
		metrics.IncCounter(MetricCmdPrependErrors)
		return err
	}

	metrics.IncCounter(MetricCmdPrependStoredL1)
	metrics.IncCounter(MetricCmdPrependStored)
	return l.res.Prepend(req.Opaque, req.Quiet)
}

func (l *L1L2BatchOrca) Add(req common.SetRequest) error {
	//log.Println("add", string(req.Key))

	// Add in L2 first, since it has the larger state
	metrics.IncCounter(MetricCmdAddL2)
	start := timer.Now()

	err := l.l2.Add(req)

	metrics.ObserveHist(HistAddL2, timer.Since(start))

	if err != nil {
		// A key already existing is not an error per se, it's a part of the
		// functionality of the add command to respond with a "not stored" in
		// the form of a ErrKeyExists. Hence no error metrics.
		if err == common.ErrKeyExists {
			metrics.IncCounter(MetricCmdAddNotStoredL2)
			metrics.IncCounter(MetricCmdAddNotStored)
			return err
		}

		// otherwise we have a real error on our hands
		metrics.IncCounter(MetricCmdAddErrorsL2)
		metrics.IncCounter(MetricCmdAddErrors)
		return err
	}

	metrics.IncCounter(MetricCmdAddStoredL2)

	// Replace the entry in L1.
	metrics.IncCounter(MetricCmdAddReplaceL1)
	start = timer.Now()

	err = l.l1.Replace(req)

	metrics.ObserveHist(HistReplaceL1, timer.Since(start))

	if err != nil {
		if err == common.ErrKeyNotFound {
			// For a replace not stored in L1, there's no problem.
			// There is no hot data to replace
			metrics.IncCounter(MetricCmdAddReplaceNotStoredL1)
		} else {
			metrics.IncCounter(MetricCmdAddReplaceErrorsL1)
			metrics.IncCounter(MetricCmdAddErrors)
			return err
		}
	} else {
		metrics.IncCounter(MetricCmdAddReplaceStoredL1)
	}

	metrics.IncCounter(MetricCmdAddStored)

	return l.res.Add(req.Opaque, req.Quiet)
}

func (l *L1L2Orca) Set(req common.SetRequest) error {
	//log.Println("set", string(req.Key))

	// Try L2 first
	metrics.IncCounter(MetricCmdSetL2)
	start := timer.Now()

	err := l.l2.Set(req)

	metrics.ObserveHist(HistSetL2, timer.Since(start))

	// If we fail to set in L2, don't set in L1
	if err != nil {
		metrics.IncCounter(MetricCmdSetErrorsL2)
		metrics.IncCounter(MetricCmdSetErrors)
		return err
	}
	metrics.IncCounter(MetricCmdSetSuccessL2)

	// Now set in L1. If L1 fails, we log the error and fail the request.
	// If a user was writing a new piece of information, the error would be OK,
	// since the next GET would be able to put the L2 information back into L1.
	// In the case that the user was overwriting information, a failed set in L1
	// and successful one in L2 would leave us inconsistent. If the response was
	// positive in this situation, it would look like the server successfully
	// processed the request but didn't store the information. Clients will
	// retry failed writes. In this case L2 will get two writes for the same key
	// but this is better because it is more correct overall, though less
	// efficient. Note there are no retries at this level.
	//
	// It should be noted that errors on a straight set are nearly always fatal
	// for the connection. It's likely that if this branch is taken that the
	// connections to everyone will be severed (for this one client connection)
	// and that the client will reconnect to try again.
	metrics.IncCounter(MetricCmdSetL1)
	start = timer.Now()

	err = l.l1.Set(req)

	metrics.ObserveHist(HistSetL1, timer.Since(start))

	if err != nil {
		metrics.IncCounter(MetricCmdSetErrorsL1)
		metrics.IncCounter(MetricCmdSetErrors)
		return err
	}

	metrics.IncCounter(MetricCmdSetSuccessL1)
	metrics.IncCounter(MetricCmdSetSuccess)

	return l.res.Set(req.Opaque, req.Quiet)
}

func (l *L1OnlyOrca) Delete(req common.DeleteRequest) error {
	//log.Println("delete", string(req.Key))

	metrics.IncCounter(MetricCmdDeleteL1)
	start := timer.Now()

	err := l.l1.Delete(req)

	metrics.ObserveHist(HistDeleteL1, timer.Since(start))

	if err == nil {
		metrics.IncCounter(MetricCmdDeleteHits)
		metrics.IncCounter(MetricCmdDeleteHitsL1)

		l.res.Delete(req.Opaque)

	} else if err == common.ErrKeyNotFound {
		metrics.IncCounter(MetricCmdDeleteMissesL1)
		metrics.IncCounter(MetricCmdDeleteMisses)
	} else {
		metrics.IncCounter(MetricCmdDeleteErrorsL1)
		metrics.IncCounter(MetricCmdDeleteErrors)
	}

	return err
}

func (l *L1OnlyOrca) Touch(req common.TouchRequest) error {
	//log.Println("touch", string(req.Key))

	metrics.IncCounter(MetricCmdTouchL1)
	start := timer.Now()

	err := l.l1.Touch(req)

	metrics.ObserveHist(HistTouchL1, timer.Since(start))

	if err == nil {
		metrics.IncCounter(MetricCmdTouchHitsL1)
		metrics.IncCounter(MetricCmdTouchHits)

		l.res.Touch(req.Opaque)

	} else if err == common.ErrKeyNotFound {
		metrics.IncCounter(MetricCmdTouchMissesL1)
		metrics.IncCounter(MetricCmdTouchMisses)
	} else {
		metrics.IncCounter(MetricCmdTouchMissesL1)
		metrics.IncCounter(MetricCmdTouchMisses)
	}

	return err
}

func (l *L1OnlyOrca) Gat(req common.GATRequest) error {
	//log.Println("gat", string(req.Key))

	metrics.IncCounter(MetricCmdGatL1)
	start := timer.Now()

	res, err := l.l1.GAT(req)

	metrics.ObserveHist(HistGatL1, timer.Since(start))

	if err == nil {
		if res.Miss {
			metrics.IncCounter(MetricCmdGatMissesL1)
			// TODO: Account for L2
			metrics.IncCounter(MetricCmdGatMisses)
		} else {
			metrics.IncCounter(MetricCmdGatHits)
			metrics.IncCounter(MetricCmdGatHitsL1)
		}
		l.res.GAT(res)
		// There is no GetEnd call required here since this is only ever
		// done in the binary protocol, where there's no END marker.
		// Calling l.res.GetEnd was a no-op here and is just useless.
		//l.res.GetEnd(0, false)
	} else {
		metrics.IncCounter(MetricCmdGatErrors)
		metrics.IncCounter(MetricCmdGatErrorsL1)
	}

	return err
}

func (l *L1OnlyOrca) Replace(req common.SetRequest) error {
	//log.Println("replace", string(req.Key))

	metrics.IncCounter(MetricCmdReplaceL1)
	start := timer.Now()

	err := l.l1.Replace(req)

	metrics.ObserveHist(HistReplaceL1, timer.Since(start))

	if err == nil {
		metrics.IncCounter(MetricCmdReplaceStoredL1)
		metrics.IncCounter(MetricCmdReplaceStored)

		err = l.res.Replace(req.Opaque, req.Quiet)

	} else if err == common.ErrKeyNotFound {
		metrics.IncCounter(MetricCmdReplaceNotStoredL1)
		metrics.IncCounter(MetricCmdReplaceNotStored)
	} else {
		metrics.IncCounter(MetricCmdReplaceErrorsL1)
		metrics.IncCounter(MetricCmdReplaceErrors)
	}

	return err
}

func (l *L1OnlyOrca) Add(req common.SetRequest) error {
	//log.Println("add", string(req.Key))

	metrics.IncCounter(MetricCmdAddL1)
	start := timer.Now()

	err := l.l1.Add(req)

	metrics.ObserveHist(HistAddL1, timer.Since(start))

	if err == nil {
		metrics.IncCounter(MetricCmdAddStoredL1)
		metrics.IncCounter(MetricCmdAddStored)

		err = l.res.Add(req.Opaque, req.Quiet)

	} else if err == common.ErrKeyExists {
		metrics.IncCounter(MetricCmdAddNotStoredL1)
		metrics.IncCounter(MetricCmdAddNotStored)
	} else {
		metrics.IncCounter(MetricCmdAddErrorsL1)
		metrics.IncCounter(MetricCmdAddErrors)
	}

	return err
}

func (l *L1L2BatchOrca) Set(req common.SetRequest) error {
	//log.Println("set", string(req.Key))

	// Try L2 first
	metrics.IncCounter(MetricCmdSetL2)
	start := timer.Now()

	err := l.l2.Set(req)

	metrics.ObserveHist(HistSetL2, timer.Since(start))

	// If we fail to set in L2, don't do anything in L1
	if err != nil {
		metrics.IncCounter(MetricCmdSetErrorsL2)
		metrics.IncCounter(MetricCmdSetErrors)
		return err
	}
	metrics.IncCounter(MetricCmdSetSuccessL2)

	// Replace the entry in L1.
	metrics.IncCounter(MetricCmdSetReplaceL1)
	start = timer.Now()

	err = l.l1.Replace(req)

	metrics.ObserveHist(HistReplaceL1, timer.Since(start))

	if err != nil {
		if err == common.ErrKeyNotFound {
			// For a replace not stored in L1, there's no problem.
			// There is no hot data to replace
			metrics.IncCounter(MetricCmdSetReplaceNotStoredL1)
		} else {
			metrics.IncCounter(MetricCmdSetReplaceErrorsL1)
			metrics.IncCounter(MetricCmdSetErrors)
			return err
		}
	} else {
		metrics.IncCounter(MetricCmdSetReplaceStoredL1)
	}

	metrics.IncCounter(MetricCmdSetSuccess)

	return l.res.Set(req.Opaque, req.Quiet)
}

func (l *L1OnlyOrca) Set(req common.SetRequest) error {
	//log.Println("set", string(req.Key))

	metrics.IncCounter(MetricCmdSetL1)
	start := timer.Now()

	err := l.l1.Set(req)

	metrics.ObserveHist(HistSetL1, timer.Since(start))

	if err == nil {
		metrics.IncCounter(MetricCmdSetSuccessL1)
		metrics.IncCounter(MetricCmdSetSuccess)

		err = l.res.Set(req.Opaque, req.Quiet)

	} else {
		metrics.IncCounter(MetricCmdSetErrorsL1)
		metrics.IncCounter(MetricCmdSetErrors)
	}

	return err
}

func (l *L1L2BatchOrca) Get(req common.GetRequest) error {
	metrics.IncCounterBy(MetricCmdGetKeys, uint64(len(req.Keys)))
	//debugString := "get"
	//for _, k := range req.Keys {
	//	debugString += " "
	//	debugString += string(k)
	//}
	//println(debugString)

	metrics.IncCounter(MetricCmdGetL1)
	metrics.IncCounterBy(MetricCmdGetKeysL1, uint64(len(req.Keys)))
	start := timer.Now()

	resChan, errChan := l.l1.Get(req)

	var err error
	//var lastres common.GetResponse
	var l2keys [][]byte
	var l2opaques []uint32
	var l2quiets []bool

	// Read all the responses back from L1.
	// The contract is that the resChan will have GetResponse's for get hits and misses,
	// and the errChan will have any other errors, such as an out of memory error from
	// memcached. If any receive happens from errChan, there will be no more responses
	// from resChan.
	for {
		select {
		case res, ok := <-resChan:
			if !ok {
				resChan = nil
			} else {
				if res.Miss {
					metrics.IncCounter(MetricCmdGetMissesL1)
					l2keys = append(l2keys, res.Key)
					l2opaques = append(l2opaques, res.Opaque)
					l2quiets = append(l2quiets, res.Quiet)
				} else {
					metrics.IncCounter(MetricCmdGetHits)
					metrics.IncCounter(MetricCmdGetHitsL1)
					l.res.Get(res)
				}
			}

		case getErr, ok := <-errChan:
			if !ok {
				errChan = nil
			} else {
				metrics.IncCounter(MetricCmdGetErrors)
				metrics.IncCounter(MetricCmdGetErrorsL1)
				err = getErr
			}
		}

		if resChan == nil && errChan == nil {
			break
		}
	}

	// record metrics before going to L2
	metrics.ObserveHist(HistGetL1, timer.Since(start))

	// leave early on all hits
	if len(l2keys) == 0 {
		if err != nil {
			return err
		}
		return l.res.GetEnd(req.NoopOpaque, req.NoopEnd)
	}

	// Time for the same dance with L2
	req = common.GetRequest{
		Keys:       l2keys,
		NoopEnd:    req.NoopEnd,
		NoopOpaque: req.NoopOpaque,
		Opaques:    l2opaques,
		Quiet:      l2quiets,
	}

	metrics.IncCounter(MetricCmdGetL2)
	metrics.IncCounterBy(MetricCmdGetKeysL2, uint64(len(l2keys)))
	start = timer.Now()

	resChan, errChan = l.l2.Get(req)

	for {
		select {
		case res, ok := <-resChan:
			if !ok {
				resChan = nil
			} else {
				if res.Miss {
					metrics.IncCounter(MetricCmdGetMissesL2)
					// Missing L2 means a true miss
					metrics.IncCounter(MetricCmdGetMisses)
				} else {
					metrics.IncCounter(MetricCmdGetHitsL2)

					// For batch, don't set in l1. Typically batch users will read
					// data once and not again, so setting in L1 will not be valuable.
//.........這裏部分代碼省略.........

func (l *L1OnlyOrca) GetE(req common.GetRequest) error {
	// For an L1 only orchestrator, this will fail if the backend is memcached.
	// It should be talking to another rend-based server, such as the L2 for the
	// EVCache server project.
	metrics.IncCounterBy(MetricCmdGetEKeys, uint64(len(req.Keys)))
	//debugString := "gete"
	//for _, k := range req.Keys {
	//	debugString += " "
	//	debugString += string(k)
	//}
	//println(debugString)

	metrics.IncCounter(MetricCmdGetEL1)
	metrics.IncCounterBy(MetricCmdGetEKeysL1, uint64(len(req.Keys)))
	start := timer.Now()

	resChan, errChan := l.l1.GetE(req)

	var err error

	// Read all the responses back from l.l1.
	// The contract is that the resChan will have GetEResponse's for get hits and misses,
	// and the errChan will have any other errors, such as an out of memory error from
	// memcached. If any receive happens from errChan, there will be no more responses
	// from resChan.
	for {
		select {
		case res, ok := <-resChan:
			if !ok {
				resChan = nil
			} else {
				if res.Miss {
					metrics.IncCounter(MetricCmdGetEMissesL1)
					metrics.IncCounter(MetricCmdGetEMisses)
				} else {
					metrics.IncCounter(MetricCmdGetEHits)
					metrics.IncCounter(MetricCmdGetEHitsL1)
				}
				l.res.GetE(res)
			}

		case getErr, ok := <-errChan:
			if !ok {
				errChan = nil
			} else {
				metrics.IncCounter(MetricCmdGetEErrors)
				metrics.IncCounter(MetricCmdGetEErrorsL1)
				err = getErr
			}
		}

		if resChan == nil && errChan == nil {
			break
		}
	}

	metrics.ObserveHist(HistGetEL1, timer.Since(start))

	if err == nil {
		l.res.GetEnd(req.NoopOpaque, req.NoopEnd)
	}

	return err
}

func (l *L1L2Orca) Touch(req common.TouchRequest) error {
	//log.Println("touch", string(req.Key))

	// Try L2 first
	metrics.IncCounter(MetricCmdTouchL2)
	start := timer.Now()

	err := l.l2.Touch(req)

	metrics.ObserveHist(HistTouchL2, timer.Since(start))

	if err != nil {
		// On a touch miss in L2 don't bother touch in L1. The data should be
		// TTL'd out within a second. This is yet another place where it's
		// possible to be inconsistent, but only for a short time. Any
		// concurrent requests will see the same behavior as this one. If the
		// touch misses here, any other request will see the same view.
		if err == common.ErrKeyNotFound {
			metrics.IncCounter(MetricCmdTouchMissesL2)
			metrics.IncCounter(MetricCmdTouchMisses)
			return err
		}

		// If we fail to touch in L2, don't touch in L1. If the touch succeeded
		// but for some reason the communication failed, then this is still OK
		// since L1 can TTL out while L2 still has the data. On the next get
		// request the data would still be retrievable, albeit more slowly.
		metrics.IncCounter(MetricCmdTouchErrorsL2)
		metrics.IncCounter(MetricCmdTouchErrors)
		return err
	}
	metrics.IncCounter(MetricCmdTouchHitsL2)

	// In the case of concurrent touches with different values, it's possible
	// that the touches for L1 and L2 interleave and produce an inconsistent
	// state. The L2 could be touched long, then L2 and L1 touched short on
	// another request, then L1 touched long. In this case the data in L1 would
	// outlive L2. This situation is uncommon and is therefore discounted.
	metrics.IncCounter(MetricCmdTouchL1)
	start = timer.Now()

	err = l.l1.Touch(req)

	metrics.ObserveHist(HistTouchL1, timer.Since(start))

	if err != nil {
		// Touch misses in L1 after a hit in L2 are nto a big deal. The
		// touch operation here explicitly does *not* act as a pre-warm putting
		// data into L1. A miss here after a hit is the same as a hit.
		if err == common.ErrKeyNotFound {
			metrics.IncCounter(MetricCmdTouchMissesL1)
			// Note that we increment the overall hits here (not misses) on
			// purpose because L2 hit.
			metrics.IncCounter(MetricCmdTouchHits)
			return l.res.Touch(req.Opaque)
		}

		metrics.IncCounter(MetricCmdTouchErrorsL1)
		metrics.IncCounter(MetricCmdTouchErrors)
		return err
	}

	metrics.IncCounter(MetricCmdTouchHitsL1)
	metrics.IncCounter(MetricCmdTouchHits)

	return l.res.Touch(req.Opaque)
}

func (l *L1L2Orca) Gat(req common.GATRequest) error {
	//log.Println("gat", string(req.Key))

	// Try L1 first
	metrics.IncCounter(MetricCmdGatL1)
	start := timer.Now()

	res, err := l.l1.GAT(req)

	metrics.ObserveHist(HistGatL1, timer.Since(start))

	// Errors here are genrally fatal to the connection, as something has gone
	// seriously wrong. Bail out early.
	// I should note that this is different than the other commands, where there
	// are some benevolent "errors" that include KeyNotFound or KeyExists. In
	// both Get and GAT the mini-internal-protocol is different because the Get
	// command uses a channel to send results back and an error channel to signal
	// some kind of fatal problem. The result signals non-fatal "errors"; in this
	// case it's ErrKeyNotFound --> res.Miss is true.
	if err != nil {
		metrics.IncCounter(MetricCmdGatErrorsL1)
		metrics.IncCounter(MetricCmdGatErrors)
		return err
	}

	if res.Miss {
		// If we miss here, we have to GAT L2 to get the data, then put it back
		// into L1 with the new TTL.
		metrics.IncCounter(MetricCmdGatMissesL1)

		metrics.IncCounter(MetricCmdGatL2)
		start = timer.Now()

		res, err = l.l2.GAT(req)

		metrics.ObserveHist(HistGatL2, timer.Since(start))

		// fatal error
		if err != nil {
			metrics.IncCounter(MetricCmdGatErrorsL2)
			metrics.IncCounter(MetricCmdGatErrors)
			return err
		}

		// A miss on L2 after L1 is a true miss
		if res.Miss {
			metrics.IncCounter(MetricCmdGatMissesL2)
			metrics.IncCounter(MetricCmdGatMisses)
			return l.res.GAT(res)
		}

		// Take the data from the L2 GAT and set into L1 with the new TTL.
		// There's several problems that could arise from interleaving of other
		// operations. Another GAT isn't a problem.
		//
		// Intermediate sets might get clobbered in L1 but remain in L2 if we
		// used Set, but since we use Add we should not overwrite a Set that
		// happens between the L2 GAT hit and subsequent L1 reconciliation.
		//
		// Deletes would be a possible problem since a delete hit in L2 and miss
		// in L1 would interleave to have data in L1 not in L2. This is a risk
		// that is understood and accepted. The typical use cases at Netflix
		// will not use deletes concurrently with GATs.
		setreq := common.SetRequest{
			Key:     req.Key,
			Exptime: req.Exptime,
			Flags:   res.Flags,
			Data:    res.Data,
		}

		metrics.IncCounter(MetricCmdGatAddL1)
		start2 := timer.Now()

		err = l.l1.Add(setreq)

		metrics.ObserveHist(HistAddL1, timer.Since(start2))

		if err != nil {
			// we were trampled in the middle of performing the GAT operation
			// In this case, it's fine; no error for the overall op. We still
			// want to track this with a metric, though, and return success.
			if err == common.ErrKeyExists {
				metrics.IncCounter(MetricCmdGatAddNotStoredL1)
			} else {
				metrics.IncCounter(MetricCmdGatAddErrorsL1)
				// Gat errors here and not Add. The metrics for L1/L2 correspond to
				// direct interaction with the two. THe overall metrics correspond
				// to the more abstract orchestrator operation.
				metrics.IncCounter(MetricCmdGatErrors)
				return err
			}
		} else {
			metrics.IncCounter(MetricCmdGatAddStoredL1)
		}

		// the overall operation succeeded
		metrics.IncCounter(MetricCmdGatHits)

	} else {
		metrics.IncCounter(MetricCmdGatHitsL1)
//.........這裏部分代碼省略.........

func (l *L1L2Orca) Get(req common.GetRequest) error {
	metrics.IncCounterBy(MetricCmdGetKeys, uint64(len(req.Keys)))
	//debugString := "get"
	//for _, k := range req.Keys {
	//	debugString += " "
	//	debugString += string(k)
	//}
	//println(debugString)

	metrics.IncCounter(MetricCmdGetL1)
	metrics.IncCounterBy(MetricCmdGetKeysL1, uint64(len(req.Keys)))
	start := timer.Now()

	resChan, errChan := l.l1.Get(req)

	var err error
	//var lastres common.GetResponse
	var l2keys [][]byte
	var l2opaques []uint32
	var l2quiets []bool

	// Read all the responses back from L1.
	// The contract is that the resChan will have GetResponse's for get hits and misses,
	// and the errChan will have any other errors, such as an out of memory error from
	// memcached. If any receive happens from errChan, there will be no more responses
	// from resChan.
	for {
		select {
		case res, ok := <-resChan:
			if !ok {
				resChan = nil
			} else {
				if res.Miss {
					metrics.IncCounter(MetricCmdGetMissesL1)
					l2keys = append(l2keys, res.Key)
					l2opaques = append(l2opaques, res.Opaque)
					l2quiets = append(l2quiets, res.Quiet)
				} else {
					metrics.IncCounter(MetricCmdGetHits)
					metrics.IncCounter(MetricCmdGetHitsL1)
					l.res.Get(res)
				}
			}

		case getErr, ok := <-errChan:
			if !ok {
				errChan = nil
			} else {
				metrics.IncCounter(MetricCmdGetErrors)
				metrics.IncCounter(MetricCmdGetErrorsL1)
				err = getErr
			}
		}

		if resChan == nil && errChan == nil {
			break
		}
	}

	// finish up metrics for overall L1 (batch) get operation
	metrics.ObserveHist(HistGetL1, timer.Since(start))

	// leave early on all hits
	if len(l2keys) == 0 {
		if err != nil {
			return err
		}
		return l.res.GetEnd(req.NoopOpaque, req.NoopEnd)
	}

	// Time for the same dance with L2
	req = common.GetRequest{
		Keys:       l2keys,
		NoopEnd:    req.NoopEnd,
		NoopOpaque: req.NoopOpaque,
		Opaques:    l2opaques,
		Quiet:      l2quiets,
	}

	metrics.IncCounter(MetricCmdGetEL2)
	metrics.IncCounterBy(MetricCmdGetEKeysL2, uint64(len(l2keys)))
	start = timer.Now()

	resChanE, errChan := l.l2.GetE(req)

	for {
		select {
		case res, ok := <-resChanE:
			if !ok {
				resChanE = nil
			} else {
				if res.Miss {
					metrics.IncCounter(MetricCmdGetEMissesL2)
					// Missing L2 means a true miss
					metrics.IncCounter(MetricCmdGetMisses)
				} else {
					metrics.IncCounter(MetricCmdGetEHitsL2)

					//set in l1
					setreq := common.SetRequest{
//.........這裏部分代碼省略.........