Examples with NonblockingStoreCallback voldemort.store.nonblockingstore.NonblockingStoreCallback used on opensource projects

Example 1 with NonblockingStoreCallback

use of voldemort.store.nonblockingstore.NonblockingStoreCallback in project voldemort by voldemort.

the class PerformParallelGetAllRequests method execute.

@SuppressWarnings("unchecked")
public void execute(final Pipeline pipeline) {
    int attempts = pipelineData.getNodeToKeysMap().size();
    final Map<Integer, Response<Iterable<ByteArray>, Object>> responses = new ConcurrentHashMap<Integer, Response<Iterable<ByteArray>, Object>>();
    final CountDownLatch latch = new CountDownLatch(attempts);
    if (logger.isTraceEnabled())
        logger.trace("Attempting " + attempts + " " + pipeline.getOperation().getSimpleName() + " operations in parallel");
    Map<ByteArray, byte[]> transforms = pipelineData.getTransforms();
    final AtomicBoolean isResponseProcessed = new AtomicBoolean(false);
    for (Map.Entry<Node, List<ByteArray>> entry : pipelineData.getNodeToKeysMap().entrySet()) {
        final Node node = entry.getKey();
        final Collection<ByteArray> keys = entry.getValue();
        NonblockingStoreCallback callback = new NonblockingStoreCallback() {

            public void requestComplete(Object result, long requestTime) {
                if (logger.isTraceEnabled())
                    logger.trace(pipeline.getOperation().getSimpleName() + " response received (" + requestTime + " ms.) from node " + node.getId());
                Response<Iterable<ByteArray>, Object> response = new Response<Iterable<ByteArray>, Object>(node, keys, result, requestTime);
                responses.put(node.getId(), response);
                latch.countDown();
                // This reduces the window where an exception is lost
                if (isResponseProcessed.get() && response.getValue() instanceof Exception)
                    if (response.getValue() instanceof InvalidMetadataException) {
                        pipelineData.reportException((InvalidMetadataException) response.getValue());
                        logger.warn("Received invalid metadata problem after a successful " + pipeline.getOperation().getSimpleName() + " call on node " + node.getId() + ", store '" + pipelineData.getStoreName() + "'");
                    } else {
                        handleResponseError(response, pipeline, failureDetector);
                    }
            }
        };
        if (logger.isTraceEnabled())
            logger.trace("Submitting " + pipeline.getOperation().getSimpleName() + " request on node " + node.getId());
        NonblockingStore store = nonblockingStores.get(node.getId());
        store.submitGetAllRequest(keys, transforms, callback, timeoutMs);
    }
    try {
        latch.await(timeoutMs, TimeUnit.MILLISECONDS);
    } catch (InterruptedException e) {
        if (logger.isEnabledFor(Level.WARN))
            logger.warn(e, e);
    }
    for (Response<Iterable<ByteArray>, Object> response : responses.values()) {
        if (response.getValue() instanceof Exception) {
            if (handleResponseError(response, pipeline, failureDetector))
                return;
        } else {
            Map<ByteArray, List<Versioned<byte[]>>> values = (Map<ByteArray, List<Versioned<byte[]>>>) response.getValue();
            for (ByteArray key : response.getKey()) {
                MutableInt successCount = pipelineData.getSuccessCount(key);
                successCount.increment();
                List<Versioned<byte[]>> retrieved = values.get(key);
                /*
                     * retrieved can be null if there are no values for the key
                     * provided
                     */
                if (retrieved != null) {
                    List<Versioned<byte[]>> existing = pipelineData.getResult().get(key);
                    if (existing == null)
                        pipelineData.getResult().put(key, Lists.newArrayList(retrieved));
                    else
                        existing.addAll(retrieved);
                }
                HashSet<Integer> zoneResponses = null;
                if (pipelineData.getKeyToZoneResponse().containsKey(key)) {
                    zoneResponses = pipelineData.getKeyToZoneResponse().get(key);
                } else {
                    zoneResponses = new HashSet<Integer>();
                    pipelineData.getKeyToZoneResponse().put(key, zoneResponses);
                }
                zoneResponses.add(response.getNode().getZoneId());
            }
            pipelineData.getResponses().add(new Response<Iterable<ByteArray>, Map<ByteArray, List<Versioned<byte[]>>>>(response.getNode(), response.getKey(), values, response.getRequestTime()));
            failureDetector.recordSuccess(response.getNode(), response.getRequestTime());
        }
    }
    isResponseProcessed.set(true);
    pipeline.addEvent(completeEvent);
}

Example 2 with NonblockingStoreCallback

use of voldemort.store.nonblockingstore.NonblockingStoreCallback in project voldemort by voldemort.

the class PerformParallelRequests method execute.

public void execute(final Pipeline pipeline) {
    List<Node> nodes = pipelineData.getNodes();
    int attempts = Math.min(preferred, nodes.size());
    final Map<Integer, Response<ByteArray, Object>> responses = new ConcurrentHashMap<Integer, Response<ByteArray, Object>>();
    final CountDownLatch latch = new CountDownLatch(attempts);
    if (logger.isTraceEnabled())
        logger.trace("Attempting " + attempts + " " + pipeline.getOperation().getSimpleName() + " operations in parallel for key " + key);
    final AtomicBoolean isResponseProcessed = new AtomicBoolean(false);
    for (int i = 0; i < attempts; i++) {
        final Node node = nodes.get(i);
        pipelineData.incrementNodeIndex();
        final long startMs = logger.isDebugEnabled() ? System.currentTimeMillis() : -1;
        NonblockingStoreCallback callback = new NonblockingStoreCallback() {

            public void requestComplete(Object result, long requestTime) {
                if (logger.isTraceEnabled())
                    logger.trace(pipeline.getOperation().getSimpleName() + " response received (" + requestTime + " ms.) from node " + node.getId() + "for key " + key);
                Response<ByteArray, Object> response = new Response<ByteArray, Object>(node, key, result, requestTime);
                if (logger.isDebugEnabled())
                    logger.debug("Finished " + pipeline.getOperation().getSimpleName() + " for key " + ByteUtils.toHexString(key.get()) + " (keyRef: " + System.identityHashCode(key) + "); started at " + startMs + " took " + requestTime + " ms on node " + node.getId() + "(" + node.getHost() + ")");
                responses.put(node.getId(), response);
                latch.countDown();
                // This reduces the window where an exception is lost
                if (isResponseProcessed.get() && response.getValue() instanceof Exception) {
                    if (response.getValue() instanceof InvalidMetadataException) {
                        pipelineData.reportException((InvalidMetadataException) response.getValue());
                        logger.warn("Received invalid metadata problem after a successful " + pipeline.getOperation().getSimpleName() + " call on node " + node.getId() + ", store '" + pipelineData.getStoreName() + "' for key " + key);
                    } else {
                        handleResponseError(response, pipeline, failureDetector);
                    }
                }
            }
        };
        if (logger.isTraceEnabled())
            logger.trace("Submitting " + pipeline.getOperation().getSimpleName() + " request on node " + node.getId() + " for key " + key);
        NonblockingStore store = nonblockingStores.get(node.getId());
        if (pipeline.getOperation() == Operation.GET)
            store.submitGetRequest(key, transforms, callback, timeoutMs);
        else if (pipeline.getOperation() == Operation.GET_VERSIONS)
            store.submitGetVersionsRequest(key, callback, timeoutMs);
        else
            throw new IllegalStateException(getClass().getName() + " does not support pipeline operation " + pipeline.getOperation());
    }
    try {
        latch.await(timeoutMs, TimeUnit.MILLISECONDS);
    } catch (InterruptedException e) {
        if (logger.isEnabledFor(Level.WARN))
            logger.warn(e, e);
    }
    for (Response<ByteArray, Object> response : responses.values()) {
        if (response.getValue() instanceof Exception) {
            if (handleResponseError(response, pipeline, failureDetector))
                return;
        } else {
            pipelineData.incrementSuccesses();
            Response<ByteArray, V> rCast = Utils.uncheckedCast(response);
            pipelineData.getResponses().add(rCast);
            failureDetector.recordSuccess(response.getNode(), response.getRequestTime());
            pipelineData.getZoneResponses().add(response.getNode().getZoneId());
        }
    }
    isResponseProcessed.set(true);
    if (logger.isDebugEnabled())
        logger.debug("GET for key " + ByteUtils.toHexString(key.get()) + " (keyRef: " + System.identityHashCode(key) + "); successes: " + pipelineData.getSuccesses() + " preferred: " + preferred + " required: " + required);
    if (pipelineData.getSuccesses() < required) {
        if (insufficientSuccessesEvent != null) {
            pipeline.addEvent(insufficientSuccessesEvent);
        } else {
            pipelineData.setFatalError(new InsufficientOperationalNodesException(required + " " + pipeline.getOperation().getSimpleName() + "s required, but only " + pipelineData.getSuccesses() + " succeeded", pipelineData.getReplicationSet(), pipelineData.getNodes(), pipelineData.getFailedNodes(), pipelineData.getFailures()));
            pipeline.abort();
        }
    } else {
        if (pipelineData.getZonesRequired() != null) {
            int zonesSatisfied = pipelineData.getZoneResponses().size();
            if (zonesSatisfied >= (pipelineData.getZonesRequired() + 1)) {
                pipeline.addEvent(completeEvent);
            } else {
                if (logger.isDebugEnabled()) {
                    logger.debug("Operation " + pipeline.getOperation().getSimpleName() + "failed due to insufficient zone responses, required " + pipelineData.getZonesRequired() + " obtained " + zonesSatisfied + " " + pipelineData.getZoneResponses() + " for key " + key);
                }
                if (this.insufficientZonesEvent != null) {
                    pipeline.addEvent(this.insufficientZonesEvent);
                } else {
                    pipelineData.setFatalError(new InsufficientZoneResponsesException((pipelineData.getZonesRequired() + 1) + " " + pipeline.getOperation().getSimpleName() + "s required zone, but only " + zonesSatisfied + " succeeded"));
                }
            }
        } else {
            pipeline.addEvent(completeEvent);
        }
    }
}

Example 3 with NonblockingStoreCallback

use of voldemort.store.nonblockingstore.NonblockingStoreCallback in project voldemort by voldemort.

the class PerformParallelDeleteRequests method executeInternal.

private void executeInternal(final Pipeline pipeline) {
    List<Node> nodes = pipelineData.getNodes();
    final Map<Integer, Response<ByteArray, Object>> responses = new ConcurrentHashMap<Integer, Response<ByteArray, Object>>();
    int attempts = nodes.size();
    int blocks = Math.min(preferred, attempts);
    final CountDownLatch attemptsLatch = new CountDownLatch(attempts);
    final CountDownLatch blocksLatch = new CountDownLatch(blocks);
    if (logger.isTraceEnabled())
        logger.trace("Attempting " + attempts + " " + pipeline.getOperation().getSimpleName() + " operations in parallel");
    long beginTime = System.nanoTime();
    for (int i = 0; i < attempts; i++) {
        final Node node = nodes.get(i);
        pipelineData.incrementNodeIndex();
        NonblockingStoreCallback callback = new NonblockingStoreCallback() {

            public void requestComplete(Object result, long requestTime) {
                if (logger.isTraceEnabled())
                    logger.trace(pipeline.getOperation().getSimpleName() + " response received (" + requestTime + " ms.) from node " + node.getId());
                Response<ByteArray, Object> response = new Response<ByteArray, Object>(node, key, result, requestTime);
                if (logger.isTraceEnabled()) {
                    logger.trace(attemptsLatch.getCount() + " attempts remaining. Will block " + " for " + blocksLatch.getCount() + " more ");
                }
                responses.put(node.getId(), response);
                if (response.getValue() instanceof Exception && isOperationCompleted.get()) {
                    handleException(response, pipeline);
                }
                attemptsLatch.countDown();
                blocksLatch.countDown();
            }
        };
        if (logger.isTraceEnabled())
            logger.info("Submitting " + pipeline.getOperation().getSimpleName() + " request on node " + node.getId());
        NonblockingStore store = nonblockingStores.get(node.getId());
        store.submitDeleteRequest(key, version, callback, timeoutMs);
    }
    try {
        long ellapsedNs = System.nanoTime() - beginTime;
        long remainingNs = (timeoutMs * Time.NS_PER_MS) - ellapsedNs;
        if (remainingNs > 0) {
            blocksLatch.await(remainingNs, TimeUnit.NANOSECONDS);
        }
    } catch (InterruptedException e) {
        if (logger.isEnabledFor(Level.WARN))
            logger.warn(e, e);
    }
    if (processResponses(responses, pipeline))
        return;
    // wait for more responses in case we did not have enough successful
    // response to achieve the required count
    boolean quorumSatisfied = true;
    if (pipelineData.getSuccesses() < required) {
        long ellapsedNs = System.nanoTime() - beginTime;
        long remainingNs = (timeoutMs * Time.NS_PER_MS) - ellapsedNs;
        if (remainingNs > 0) {
            try {
                attemptsLatch.await(remainingNs, TimeUnit.NANOSECONDS);
            } catch (InterruptedException e) {
                if (logger.isEnabledFor(Level.WARN))
                    logger.warn(e, e);
            }
            if (processResponses(responses, pipeline))
                return;
        }
        if (pipelineData.getSuccesses() < required) {
            pipelineData.setFatalError(new InsufficientOperationalNodesException(required + " " + pipeline.getOperation().getSimpleName() + "s required, but only " + pipelineData.getSuccesses() + " succeeded", pipelineData.getReplicationSet(), pipelineData.getNodes(), pipelineData.getFailedNodes(), pipelineData.getFailures()));
            abortPipeline(pipeline);
            quorumSatisfied = false;
        }
    }
    if (quorumSatisfied) {
        if (pipelineData.getZonesRequired() != null) {
            int zonesSatisfied = pipelineData.getZoneResponses().size();
            if (zonesSatisfied >= (pipelineData.getZonesRequired() + 1)) {
                completePipeline(pipeline);
            } else {
                long timeMs = (System.nanoTime() - beginTime) / Time.NS_PER_MS;
                if ((timeoutMs - timeMs) > 0) {
                    try {
                        attemptsLatch.await(timeoutMs - timeMs, TimeUnit.MILLISECONDS);
                    } catch (InterruptedException e) {
                        if (logger.isEnabledFor(Level.WARN))
                            logger.warn(e, e);
                    }
                    if (processResponses(responses, pipeline))
                        return;
                }
                if (pipelineData.getZoneResponses().size() >= (pipelineData.getZonesRequired() + 1)) {
                    completePipeline(pipeline);
                } else {
                    pipelineData.setFatalError(new InsufficientZoneResponsesException((pipelineData.getZonesRequired() + 1) + " " + pipeline.getOperation().getSimpleName() + "s required zone, but only " + zonesSatisfied + " succeeded"));
                    abortPipeline(pipeline);
                }
            }
        } else {
            completePipeline(pipeline);
        }
    }
}

Example 4 with NonblockingStoreCallback

use of voldemort.store.nonblockingstore.NonblockingStoreCallback in project voldemort by voldemort.

the class PerformParallelPutRequests method execute.

@Override
public void execute(final Pipeline pipeline) {
    final Node masterNode = pipelineData.getMaster();
    final List<Node> nodes = pipelineData.getNodes();
    final Versioned<byte[]> versionedCopy = pipelineData.getVersionedCopy();
    final Integer numNodesTouchedInSerialPut = nodes.indexOf(masterNode) + 1;
    numNodesPendingResponse = nodes.size() - numNodesTouchedInSerialPut;
    if (logger.isDebugEnabled())
        logger.debug("PUT {key:" + key + "} MasterNode={id:" + masterNode.getId() + "} totalNodesToAsyncPut=" + numNodesPendingResponse);
    // initiate parallel puts
    for (int i = numNodesTouchedInSerialPut; i < nodes.size(); i++) {
        final Node node = nodes.get(i);
        pipelineData.incrementNodeIndex();
        NonblockingStoreCallback callback = new NonblockingStoreCallback() {

            @Override
            public void requestComplete(Object result, long requestTime) {
                boolean responseHandledByMaster = false;
                if (logger.isDebugEnabled())
                    logger.debug("PUT {key:" + key + "} response received from node={id:" + node.getId() + "} in " + requestTime + " ms)");
                Response<ByteArray, Object> response;
                response = new Response<ByteArray, Object>(node, key, result, requestTime);
                if (logger.isDebugEnabled()) {
                    logger.debug("PUT {key:" + key + "} Parallel put thread trying to return result to main thread");
                }
                responseHandledByMaster = pipelineData.getSynchronizer().tryDelegateResponseHandling(response);
                if (logger.isDebugEnabled()) {
                    logger.debug("PUT {key:" + key + "} Master thread accepted the response: " + responseHandledByMaster);
                }
                if (!responseHandledByMaster) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("PUT {key:" + key + "} Master thread did not accept the response: will handle in worker thread");
                    }
                    if (PipelineRoutedStore.isSlopableFailure(response.getValue()) || response.getValue() instanceof QuotaExceededException) {
                        if (logger.isDebugEnabled())
                            logger.debug("PUT {key:" + key + "} failed on node={id:" + node.getId() + ",host:" + node.getHost() + "}");
                        if (isHintedHandoffEnabled()) {
                            boolean triedDelegateSlop = pipelineData.getSynchronizer().tryDelegateSlop(node);
                            if (logger.isDebugEnabled()) {
                                logger.debug("PUT {key:" + key + "} triedDelegateSlop: " + triedDelegateSlop);
                            }
                            if (!triedDelegateSlop) {
                                Slop slop = new Slop(pipelineData.getStoreName(), Slop.Operation.PUT, key, versionedCopy.getValue(), transforms, node.getId(), new Date());
                                pipelineData.addFailedNode(node);
                                if (logger.isDebugEnabled())
                                    logger.debug("PUT {key:" + key + "} Start registering Slop(node:" + node.getId() + ",host:" + node.getHost() + ")");
                                hintedHandoff.sendHintParallel(node, versionedCopy.getVersion(), slop);
                                if (logger.isDebugEnabled())
                                    logger.debug("PUT {key:" + key + "} Sent out request to register Slop(node: " + node.getId() + ",host:" + node.getHost() + ")");
                            }
                        }
                    } else {
                        // the exception is ignorable
                        if (logger.isDebugEnabled()) {
                            if (result instanceof Exception) {
                                logger.debug("PUT {key:" + key + "} will not send hint. Response is ignorable exception: " + result.getClass().toString());
                            } else {
                                logger.debug("PUT {key:" + key + "} will not send hint. Response is success");
                            }
                        }
                    }
                    if (result instanceof Exception && !(result instanceof ObsoleteVersionException)) {
                        if (response.getValue() instanceof InvalidMetadataException) {
                            pipelineData.reportException((InvalidMetadataException) response.getValue());
                            logger.warn("Received invalid metadata problem after a successful " + pipeline.getOperation().getSimpleName() + " call on node " + node.getId() + ", store '" + pipelineData.getStoreName() + "'");
                        } else if (response.getValue() instanceof QuotaExceededException) {
                            /**
                             * TODO Not sure if we need to count this
                             * Exception for stats or silently ignore and
                             * just log a warning. While
                             * QuotaExceededException thrown from other
                             * places mean the operation failed, this one
                             * does not fail the operation but instead
                             * stores slops. Introduce a new Exception in
                             * client side to just monitor how mamy Async
                             * writes fail on exceeding Quota?
                             */
                            logger.warn("Received QuotaExceededException after a successful " + pipeline.getOperation().getSimpleName() + " call on node " + node.getId() + ", store '" + pipelineData.getStoreName() + "', master-node '" + masterNode.getId() + "'");
                        } else {
                            handleResponseError(response, pipeline, failureDetector);
                        }
                    }
                }
            }
        };
        if (logger.isTraceEnabled())
            logger.trace("Submitting " + pipeline.getOperation().getSimpleName() + " request on node " + node.getId() + " for key " + key);
        NonblockingStore store = nonblockingStores.get(node.getId());
        store.submitPutRequest(key, versionedCopy, transforms, callback, timeoutMs);
    }
    try {
        boolean preferredSatisfied = false;
        while (true) {
            long elapsedNs = System.nanoTime() - pipelineData.getStartTimeNs();
            long remainingNs = (timeoutMs * Time.NS_PER_MS) - elapsedNs;
            remainingNs = Math.max(0, remainingNs);
            // preferred check
            if (numResponsesGot >= preferred - 1) {
                preferredSatisfied = true;
            }
            quorumSatisfied = isQuorumSatisfied();
            zonesSatisfied = isZonesSatisfied();
            if (quorumSatisfied && zonesSatisfied && preferredSatisfied || remainingNs <= 0 || numNodesPendingResponse <= 0) {
                pipelineData.getSynchronizer().cutoffHandling();
                break;
            } else {
                if (logger.isTraceEnabled()) {
                    logger.trace("PUT {key:" + key + "} trying to poll from queue");
                }
                Response<ByteArray, Object> response = pipelineData.getSynchronizer().responseQueuePoll(remainingNs, TimeUnit.NANOSECONDS);
                processResponse(response, pipeline);
                if (logger.isTraceEnabled()) {
                    logger.trace("PUT {key:" + key + "} tried to poll from queue. Null?: " + (response == null) + " numResponsesGot:" + numResponsesGot + " parallelResponseToWait: " + numNodesPendingResponse + "; preferred-1: " + (preferred - 1) + "; preferredOK: " + preferredSatisfied + " quorumOK: " + quorumSatisfied + "; zoneOK: " + zonesSatisfied);
                }
            }
        }
        // leftover)
        while (!pipelineData.getSynchronizer().responseQueueIsEmpty()) {
            Response<ByteArray, Object> response = pipelineData.getSynchronizer().responseQueuePoll(0, TimeUnit.NANOSECONDS);
            processResponse(response, pipeline);
        }
        quorumSatisfied = isQuorumSatisfied();
        zonesSatisfied = isZonesSatisfied();
        if (quorumSatisfied && zonesSatisfied) {
            if (logger.isDebugEnabled()) {
                logger.debug("PUT {key:" + key + "} succeeded at parallel put stage");
            }
            pipelineData.getSynchronizer().disallowDelegateSlop();
            pipeline.addEvent(completeEvent);
        } else {
            VoldemortException fatalError;
            if (!quorumSatisfied) {
                if (logger.isDebugEnabled()) {
                    logger.debug("PUT {key:" + key + "} failed due to insufficient nodes. required=" + required + " success=" + pipelineData.getSuccesses());
                }
                fatalError = new InsufficientOperationalNodesException(required + " " + pipeline.getOperation().getSimpleName() + "s required, but only " + pipelineData.getSuccesses() + " succeeded", pipelineData.getReplicationSet(), pipelineData.getNodes(), pipelineData.getFailedNodes(), pipelineData.getFailures());
                pipelineData.setFatalError(fatalError);
            } else if (!zonesSatisfied) {
                if (logger.isDebugEnabled()) {
                    logger.debug("PUT {key:" + key + "} failed due to insufficient zones. required=" + pipelineData.getZonesRequired() + 1 + " success=" + pipelineData.getZoneResponses().size());
                }
                fatalError = new InsufficientZoneResponsesException((pipelineData.getZonesRequired() + 1) + " " + pipeline.getOperation().getSimpleName() + "s required zone, but only " + (pipelineData.getZoneResponses().size()) + " succeeded. Failing nodes : " + pipelineData.getFailedNodes());
                pipelineData.setFatalError(fatalError);
            }
            pipeline.abort();
        }
    } catch (InterruptedException e) {
        if (logger.isEnabledFor(Level.WARN))
            logger.warn(e, e);
    } catch (NoSuchElementException e) {
        if (logger.isEnabledFor(Level.ERROR))
            logger.error("Response Queue is empty. There may be a bug in PerformParallelPutRequest", e);
    } finally {
        if (logger.isDebugEnabled()) {
            logger.debug("PUT {key:" + key + "} marking parallel put stage finished");
        }
    }
}

Example 5 with NonblockingStoreCallback

use of voldemort.store.nonblockingstore.NonblockingStoreCallback in project voldemort by voldemort.

the class ClientRequestExecutorFactory method createAsync.

/**
 * Create a ClientRequestExecutor for the given {@link SocketDestination}.
 *
 * @param dest {@link SocketDestination}
 */
@Override
public void createAsync(final SocketDestination dest, final KeyedResourcePool<SocketDestination, ClientRequestExecutor> pool) throws Exception {
    int numCreated = created.incrementAndGet();
    if (logger.isDebugEnabled())
        logger.debug("Creating socket " + numCreated + " for " + dest.getHost() + ":" + dest.getPort() + " using protocol " + dest.getRequestFormatType().getCode());
    SocketChannel socketChannel = null;
    ClientRequestExecutor clientRequestExecutor = null;
    long durationMs = 0;
    try {
        socketChannel = SocketChannel.open();
        socketChannel.socket().setReceiveBufferSize(this.socketBufferSize);
        socketChannel.socket().setSendBufferSize(this.socketBufferSize);
        socketChannel.socket().setTcpNoDelay(true);
        socketChannel.socket().setSoTimeout(soTimeoutMs);
        socketChannel.socket().setKeepAlive(this.socketKeepAlive);
        socketChannel.configureBlocking(false);
        socketChannel.connect(new InetSocketAddress(dest.getHost(), dest.getPort()));
        if (logger.isDebugEnabled()) {
            logger.debug("Created socket " + numCreated + " for " + dest.getHost() + ":" + dest.getPort() + " using protocol " + dest.getRequestFormatType().getCode() + " after " + durationMs + " ms.");
        }
        ClientRequestSelectorManager selectorManager = selectorManagers[counter.getAndIncrement() % selectorManagers.length];
        Selector selector = selectorManager.getSelector();
        clientRequestExecutor = new ClientRequestExecutor(selector, socketChannel, socketBufferSize, idleConnectionTimeoutNs, dest);
        int timeoutMs = this.getTimeout();
        ProtocolNegotiatorClientRequest protocolRequest = new ProtocolNegotiatorClientRequest(dest.getRequestFormatType());
        NonblockingStoreCallback callback = new NonblockingStoreCallback() {

            @Override
            public void requestComplete(Object result, long requestTime) {
                if (result instanceof Exception) {
                    Exception e = (Exception) result;
                    /*
                         * There are 2 places where we can get a store timeout
                         * Exception
                         * 
                         * 1) While doing connect - the machine was up once, but
                         * not anymore. In that case, TCP SYN will be sent by
                         * the client, but server would not sent TCP ACK as it
                         * is dead.
                         * 
                         * 2) After connect doing Protocol Negotiation - Most
                         * likely the server and kernel is up, but the process
                         * is in a zombie state because of hard drive failure or
                         * stuck in shutdown or doing a GC. This can be
                         * intermittent or hard failures. Before this code
                         * change, if the process entered this state, Voldemort
                         * clients may not detect the failure immediately. They
                         * are treated as normal errors, instead of catastrophic
                         * erros.This was the reason before it is better to kill
                         * the process on a machine and let the machine stay up.
                         * After this code change they will be treated as
                         * connection failures ( catastrophic errors) to help
                         * recover the clients faster.
                         * 
                         * The second case can increase the false positives, but
                         * if a server is consistently timing out it is better
                         * to treat the server as dead and let the clients
                         * recover faster.
                         */
                    if (e instanceof StoreTimeoutException) {
                        e = new UnreachableStoreException("Error establishing connection for destination " + dest, new ConnectException(e.getMessage()));
                    }
                    if (logger.isDebugEnabled()) {
                        logger.debug("Reporting exception to pool " + e.getClass() + " for destination " + dest);
                    }
                    pool.reportException(dest, e);
                }
            }
        };
        NonblockingStoreCallbackClientRequest<String> clientRequest = new NonblockingStoreCallbackClientRequest<String>(pool, dest, protocolRequest, clientRequestExecutor, callback, stats);
        clientRequestExecutor.setConnectRequest(clientRequest, timeoutMs);
        selectorManager.add(clientRequestExecutor);
        selector.wakeup();
    } catch (Exception e) {
        // Make sure not to leak socketChannels
        if (socketChannel != null) {
            try {
                socketChannel.close();
            } catch (Exception ex) {
                if (logger.isEnabledFor(Level.WARN))
                    logger.warn(ex, ex);
            }
        }
        throw UnreachableStoreException.wrap("Error establishing connection for destination " + dest, e);
    }
    if (stats != null) {
        stats.incrementCount(dest, ClientSocketStats.Tracked.CONNECTION_CREATED_EVENT);
        stats.recordConnectionEstablishmentTimeUs(dest, durationMs * Time.US_PER_MS);
    }
}