/// <exception cref="Org.Apache.Hadoop.Security.Token.SecretManager.InvalidToken"/> private BlockReader GetBlockReaderLocal() { if (Log.IsTraceEnabled()) { Log.Trace(this + ": trying to construct a BlockReaderLocal " + "for short-circuit reads." ); } if (pathInfo == null) { pathInfo = clientContext.GetDomainSocketFactory().GetPathInfo(inetSocketAddress, conf); } if (!pathInfo.GetPathState().GetUsableForShortCircuit()) { PerformanceAdvisory.Log.Debug(this + ": " + pathInfo + " is not " + "usable for short circuit; giving up on BlockReaderLocal." ); return(null); } ShortCircuitCache cache = clientContext.GetShortCircuitCache(); ExtendedBlockId key = new ExtendedBlockId(block.GetBlockId(), block.GetBlockPoolId ()); ShortCircuitReplicaInfo info = cache.FetchOrCreate(key, this); SecretManager.InvalidToken exc = info.GetInvalidTokenException(); if (exc != null) { if (Log.IsTraceEnabled()) { Log.Trace(this + ": got InvalidToken exception while trying to " + "construct BlockReaderLocal via " + pathInfo.GetPath()); } throw exc; } if (info.GetReplica() == null) { if (Log.IsTraceEnabled()) { PerformanceAdvisory.Log.Debug(this + ": failed to get " + "ShortCircuitReplica. Cannot construct " + "BlockReaderLocal via " + pathInfo.GetPath()); } return(null); } return(new BlockReaderLocal.Builder(conf).SetFilename(fileName).SetBlock(block).SetStartOffset (startOffset).SetShortCircuitReplica(info.GetReplica()).SetVerifyChecksum(verifyChecksum ).SetCachingStrategy(cachingStrategy).SetStorageType(storageType).Build()); }
/// <summary>Fetch a pair of short-circuit block descriptors from a local DataNode.</summary> /// <returns> /// Null if we could not communicate with the datanode, /// a new ShortCircuitReplicaInfo object otherwise. /// ShortCircuitReplicaInfo objects may contain either an InvalidToken /// exception, or a ShortCircuitReplica object ready to use. /// </returns> public virtual ShortCircuitReplicaInfo CreateShortCircuitReplicaInfo() { if (createShortCircuitReplicaInfoCallback != null) { ShortCircuitReplicaInfo info = createShortCircuitReplicaInfoCallback.CreateShortCircuitReplicaInfo (); if (info != null) { return(info); } } if (Log.IsTraceEnabled()) { Log.Trace(this + ": trying to create ShortCircuitReplicaInfo."); } BlockReaderFactory.BlockReaderPeer curPeer; while (true) { curPeer = NextDomainPeer(); if (curPeer == null) { break; } if (curPeer.fromCache) { remainingCacheTries--; } DomainPeer peer = (DomainPeer)curPeer.peer; ShortCircuitShm.Slot slot = null; ShortCircuitCache cache = clientContext.GetShortCircuitCache(); try { MutableBoolean usedPeer = new MutableBoolean(false); slot = cache.AllocShmSlot(datanode, peer, usedPeer, new ExtendedBlockId(block.GetBlockId (), block.GetBlockPoolId()), clientName); if (usedPeer.BooleanValue()) { if (Log.IsTraceEnabled()) { Log.Trace(this + ": allocShmSlot used up our previous socket " + peer.GetDomainSocket () + ". Allocating a new one..."); } curPeer = NextDomainPeer(); if (curPeer == null) { break; } peer = (DomainPeer)curPeer.peer; } ShortCircuitReplicaInfo info = RequestFileDescriptors(peer, slot); clientContext.GetPeerCache().Put(datanode, peer); return(info); } catch (IOException e) { if (slot != null) { cache.FreeSlot(slot); } if (curPeer.fromCache) { // Handle an I/O error we got when using a cached socket. // These are considered less serious, because the socket may be stale. if (Log.IsDebugEnabled()) { Log.Debug(this + ": closing stale domain peer " + peer, e); } IOUtils.Cleanup(Log, peer); } else { // Handle an I/O error we got when using a newly created socket. // We temporarily disable the domain socket path for a few minutes in // this case, to prevent wasting more time on it. Log.Warn(this + ": I/O error requesting file descriptors. " + "Disabling domain socket " + peer.GetDomainSocket(), e); IOUtils.Cleanup(Log, peer); clientContext.GetDomainSocketFactory().DisableDomainSocketPath(pathInfo.GetPath() ); return(null); } } } return(null); }