Package com.linkedin.venice.router.api

Class VeniceDelegateMode

java.lang.Object

com.linkedin.alpini.router.api.ScatterGatherMode

com.linkedin.venice.router.api.VeniceDelegateMode

public class VeniceDelegateMode
extends ScatterGatherMode

This class contains all the ScatterGatherMode being used in Venice Router. IMPORTANT!!! In scatter(com.linkedin.alpini.router.api.Scatter<H, P, K>, java.lang.String, java.lang.String, com.linkedin.alpini.router.api.PartitionFinder<K>, com.linkedin.alpini.router.api.HostFinder<H, R>, com.linkedin.alpini.router.api.HostHealthMonitor<H>, R) function, only RouterException is expected, otherwise, the netty buffer leaking issue will happen. This vulnerability is related to Alpini since ScatterGatherMode.scatter(com.linkedin.alpini.router.api.Scatter<H, P, K>, java.lang.String, java.lang.String, com.linkedin.alpini.router.api.PartitionFinder<K>, com.linkedin.alpini.router.api.HostFinder<H, R>, com.linkedin.alpini.router.api.HostHealthMonitor<H>, R) only catches RouterException to return the exceptional future, otherwise, that function will throw exception to miss the release operation in ScatterGatherRequestHandlerImpl.prepareRetry(com.linkedin.alpini.base.concurrency.AsyncFuture<H>, P, BHS, R, com.linkedin.alpini.base.concurrency.AsyncPromise<java.util.List<HR>>, com.linkedin.alpini.base.concurrency.AsyncFuture<java.lang.Void>, java.util.concurrent.Executor, com.linkedin.alpini.router.api.HostHealthMonitor<H>, com.linkedin.alpini.router.monitoring.ScatterGatherStats.Delta, com.linkedin.alpini.base.misc.Metrics). Here are the details: 1. If the current implementation of scatter(com.linkedin.alpini.router.api.Scatter<H, P, K>, java.lang.String, java.lang.String, com.linkedin.alpini.router.api.PartitionFinder<K>, com.linkedin.alpini.router.api.HostFinder<H, R>, com.linkedin.alpini.router.api.HostHealthMonitor<H>, R) throws other exceptions than RouterException, ScatterGatherMode.scatter(com.linkedin.alpini.router.api.Scatter<H, P, K>, java.lang.String, java.lang.String, com.linkedin.alpini.router.api.PartitionFinder<K>, com.linkedin.alpini.router.api.HostFinder<H, R>, com.linkedin.alpini.router.api.HostHealthMonitor<H>, R) will rethrow the exception instead of returning an exceptional future. 2. For long-tail retry, ScatterGatherRequestHandlerImpl.prepareRetry(com.linkedin.alpini.base.concurrency.AsyncFuture<H>, P, BHS, R, com.linkedin.alpini.base.concurrency.AsyncPromise<java.util.List<HR>>, com.linkedin.alpini.base.concurrency.AsyncFuture<java.lang.Void>, java.util.concurrent.Executor, com.linkedin.alpini.router.api.HostHealthMonitor<H>, com.linkedin.alpini.router.monitoring.ScatterGatherStats.Delta, com.linkedin.alpini.base.misc.Metrics) will retain the request every time, and it will try to release the request in the handling function of "_scatterGatherHelper.scatter" in ScatterGatherRequestHandlerImpl.prepareRetry(com.linkedin.alpini.base.concurrency.AsyncFuture<H>, P, BHS, R, com.linkedin.alpini.base.concurrency.AsyncPromise<java.util.List<HR>>, com.linkedin.alpini.base.concurrency.AsyncFuture<java.lang.Void>, java.util.concurrent.Executor, com.linkedin.alpini.router.api.HostHealthMonitor<H>, com.linkedin.alpini.router.monitoring.ScatterGatherStats.Delta, com.linkedin.alpini.base.misc.Metrics). 3. If #1 happens, the handling function mentioned in #2 won't be invoked, which means the release won't happen, and this is causing the request leaking. TODO: maybe we should improve DDS lib to catch all kinds of exception in ScatterGatherMode.scatter(com.linkedin.alpini.router.api.Scatter<H, P, K>, java.lang.String, java.lang.String, com.linkedin.alpini.router.api.PartitionFinder<K>, com.linkedin.alpini.router.api.HostFinder<H, R>, com.linkedin.alpini.router.api.HostHealthMonitor<H>, R) to avoid this potential leaking issue.

Field Summary

Fields inherited from class com.linkedin.alpini.router.api.ScatterGatherMode

BROADCAST_BY_PARTITION, BROADCAST_BY_PRIMARY_HOST, GROUP_BY_GREEDY_HOST, GROUP_BY_PARTITION, GROUP_BY_PRIMARY_HOST

Constructor Summary

Constructors

Constructor	Description
VeniceDelegateMode(VeniceRouterConfig config, RouterStats<AggRouterHttpRequestStats> routerStats, RouteHttpRequestStats routeHttpRequestStats)

Method Summary

Modifier and Type	Method	Description
void	initHelixGroupSelector(HelixGroupSelector helixGroupSelector)
void	initReadRequestThrottler(RouterThrottler requestThrottler)
<H,P extends ResourcePath<K>,K,R> Scatter<H,P,K>	scatter(Scatter<H,P,K> scatter, java.lang.String requestMethod, java.lang.String resourceName, PartitionFinder<K> partitionFinder, HostFinder<H,R> hostFinder, HostHealthMonitor<H> hostHealthMonitor, R roles)	Deprecated method is compatible to old method signature.

Methods inherited from class com.linkedin.alpini.router.api.ScatterGatherMode

asBroadcast, asScatter, equals, hashCode, scatter, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

VeniceDelegateMode

public VeniceDelegateMode(VeniceRouterConfig config,
                          RouterStats<AggRouterHttpRequestStats> routerStats,
                          RouteHttpRequestStats routeHttpRequestStats)

Method Detail

initReadRequestThrottler

public void initReadRequestThrottler(RouterThrottler requestThrottler)

initHelixGroupSelector

public void initHelixGroupSelector(HelixGroupSelector helixGroupSelector)

scatter

@Nonnull
public <H,P extends ResourcePath<K>,K,R> Scatter<H,P,K> scatter(@Nonnull
                                                                                              Scatter<H,P,K> scatter,
                                                                                              @Nonnull
                                                                                              java.lang.String requestMethod,
                                                                                              @Nonnull
                                                                                              java.lang.String resourceName,
                                                                                              @Nonnull
                                                                                              PartitionFinder<K> partitionFinder,
                                                                                              @Nonnull
                                                                                              HostFinder<H,R> hostFinder,
                                                                                              @Nonnull
                                                                                              HostHealthMonitor<H> hostHealthMonitor,
                                                                                              @Nonnull
                                                                                              R roles)
                                                                                       throws RouterException

Description copied from class: ScatterGatherMode

Deprecated method is compatible to old method signature.

Overrides:

scatter in class ScatterGatherMode

Throws:

RouterException