tanvipenumudy commented on code in PR #7550: URL: https://github.com/apache/ozone/pull/7550#discussion_r2151363323
########## hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/scm/client/OMBlockPrefetchClient.java: ########## @@ -0,0 +1,367 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.hadoop.hdds.scm.client; + +import static org.apache.hadoop.hdds.scm.net.NetConstants.NODE_COST_DEFAULT; +import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_OM_PREFETCHED_BLOCKS_EXPIRY_INTERVAL; +import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_OM_PREFETCHED_BLOCKS_EXPIRY_INTERVAL_DEFAULT; +import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_OM_PREFETCH_MAX_BLOCKS; +import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_OM_PREFETCH_MAX_BLOCKS_DEFAULT; +import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_OM_PREFETCH_MIN_BLOCKS; +import static org.apache.hadoop.ozone.OzoneConfigKeys.OZONE_OM_PREFETCH_MIN_BLOCKS_DEFAULT; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.Objects; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentLinkedDeque; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.TimeoutException; +import java.util.concurrent.atomic.AtomicBoolean; +import org.apache.commons.lang3.StringUtils; +import org.apache.hadoop.hdds.client.ECReplicationConfig; +import org.apache.hadoop.hdds.client.ReplicationConfig; +import org.apache.hadoop.hdds.conf.ConfigurationSource; +import org.apache.hadoop.hdds.conf.OzoneConfiguration; +import org.apache.hadoop.hdds.protocol.DatanodeDetails; +import org.apache.hadoop.hdds.protocol.proto.HddsProtos; +import org.apache.hadoop.hdds.scm.ScmConfigKeys; +import org.apache.hadoop.hdds.scm.container.common.helpers.AllocatedBlock; +import org.apache.hadoop.hdds.scm.container.common.helpers.ExcludeList; +import org.apache.hadoop.hdds.scm.net.InnerNode; +import org.apache.hadoop.hdds.scm.net.NetworkTopology; +import org.apache.hadoop.hdds.scm.net.Node; +import org.apache.hadoop.hdds.scm.net.NodeImpl; +import org.apache.hadoop.hdds.scm.protocol.ScmBlockLocationProtocol; +import org.apache.hadoop.net.CachedDNSToSwitchMapping; +import org.apache.hadoop.net.DNSToSwitchMapping; +import org.apache.hadoop.net.TableMapping; +import org.apache.hadoop.util.ReflectionUtils; +import org.apache.hadoop.util.Time; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * OMBlockPrefetchClient manages block prefetching for efficient write operations. + * It maintains a queue of allocated blocks per replication configuration and removes expired blocks lazily. + * The client refills the queue in the background to handle high-throughput scenarios efficiently. + */ +public class OMBlockPrefetchClient { + private static final Logger LOG = LoggerFactory.getLogger(OMBlockPrefetchClient.class); + private final ScmBlockLocationProtocol scmBlockLocationProtocol; + private int maxBlocks; + private int minBlocks; + private final boolean isAllocateBlockCacheEnabled; + private DNSToSwitchMapping dnsToSwitchMapping; + private final Map<ReplicationConfig, ConcurrentLinkedDeque<ExpiringAllocatedBlock>> blockQueueMap = + new ConcurrentHashMap<>(); + private long expiryDuration; + private OMBlockPrefetchMetrics metrics; + private ExecutorService prefetchExecutor; + private final AtomicBoolean isPrefetching = new AtomicBoolean(false); + + public OMBlockPrefetchClient(ScmBlockLocationProtocol scmBlockClient, boolean isAllocateBlockCacheEnabled) { + this.scmBlockLocationProtocol = scmBlockClient; + this.isAllocateBlockCacheEnabled = isAllocateBlockCacheEnabled; + initializeBlockQueueMap(); + } + + /** + * Enum representing the replication configurations that are tested. + */ + public enum TestedReplicationConfig { + RATIS_THREE(ReplicationConfig.fromProtoTypeAndFactor( + HddsProtos.ReplicationType.RATIS, HddsProtos.ReplicationFactor.THREE)), + + RATIS_ONE(ReplicationConfig.fromProtoTypeAndFactor( + HddsProtos.ReplicationType.RATIS, HddsProtos.ReplicationFactor.ONE)), + + RS_3_2_1024(ReplicationConfig.fromProto( + HddsProtos.ReplicationType.EC, null, + toProto(3, 2, ECReplicationConfig.EcCodec.RS, 1024))), + + RS_6_3_1024(ReplicationConfig.fromProto( + HddsProtos.ReplicationType.EC, null, + toProto(6, 3, ECReplicationConfig.EcCodec.RS, 1024))), + + XOR_10_4_4096(ReplicationConfig.fromProto( + HddsProtos.ReplicationType.EC, null, + toProto(10, 4, ECReplicationConfig.EcCodec.XOR, 4096))); + + private final ReplicationConfig config; + + TestedReplicationConfig(ReplicationConfig config) { + this.config = config; + } + + public ReplicationConfig getConfig() { + return config; + } + + public static HddsProtos.ECReplicationConfig toProto(int data, int parity, ECReplicationConfig.EcCodec codec, + int ecChunkSize) { + return HddsProtos.ECReplicationConfig.newBuilder() + .setData(data) + .setParity(parity) + .setCodec(codec.toString()) + .setEcChunkSize(ecChunkSize) + .build(); + } + } + + private void initializeBlockQueueMap() { + for (TestedReplicationConfig config : TestedReplicationConfig.values()) { + blockQueueMap.put(config.getConfig(), new ConcurrentLinkedDeque<>()); + } + } + + /** + * Tracks an allocated block to be cached with its cache expiry. + */ + public static final class ExpiringAllocatedBlock { + private final AllocatedBlock block; + private final long expiryTime; + + public ExpiringAllocatedBlock(AllocatedBlock block, long expiryTime) { + this.block = block; + this.expiryTime = expiryTime; + } + + public AllocatedBlock getBlock() { + return block; + } + + public long getExpiryTime() { + return expiryTime; + } + } + + public void start(ConfigurationSource conf) throws IOException, InterruptedException, TimeoutException { + maxBlocks = conf.getInt(OZONE_OM_PREFETCH_MAX_BLOCKS, OZONE_OM_PREFETCH_MAX_BLOCKS_DEFAULT); + minBlocks = conf.getInt(OZONE_OM_PREFETCH_MIN_BLOCKS, OZONE_OM_PREFETCH_MIN_BLOCKS_DEFAULT); + expiryDuration = conf.getTimeDuration(OZONE_OM_PREFETCHED_BLOCKS_EXPIRY_INTERVAL, + OZONE_OM_PREFETCHED_BLOCKS_EXPIRY_INTERVAL_DEFAULT, TimeUnit.MILLISECONDS); + + Class<? extends DNSToSwitchMapping> dnsToSwitchMappingClass = + conf.getClass(ScmConfigKeys.NET_TOPOLOGY_NODE_SWITCH_MAPPING_IMPL_KEY, + TableMapping.class, DNSToSwitchMapping.class); + DNSToSwitchMapping newInstance = ReflectionUtils.newInstance( + dnsToSwitchMappingClass, OzoneConfiguration.of(conf)); + dnsToSwitchMapping = + ((newInstance instanceof CachedDNSToSwitchMapping) ? newInstance + : new CachedDNSToSwitchMapping(newInstance)); + metrics = OMBlockPrefetchMetrics.register(); + prefetchExecutor = Executors.newSingleThreadExecutor(r -> { + Thread t = new Thread(r, "OMBlockPrefetchClient-AsyncPrefetcher"); + t.setDaemon(true); + return t; + }); + LOG.info("OMBlockPrefetchClient started with minBlocks={}, maxBlocks={}, expiryDuration={}ms. Prefetch executor " + + "initialized.", minBlocks, maxBlocks, expiryDuration); + } + + public void stop() { + if (prefetchExecutor != null) { + prefetchExecutor.shutdown(); + try { + if (!prefetchExecutor.awaitTermination(5, TimeUnit.SECONDS)) { + prefetchExecutor.shutdownNow(); + } + } catch (InterruptedException e) { + LOG.error("Interrupted while shutting down executor service.", e); + Thread.currentThread().interrupt(); + } + } + OMBlockPrefetchMetrics.unregister(); + } + + @SuppressWarnings("parameternumber") + public List<AllocatedBlock> getBlocks(long scmBlockSize, int numBlocks, ReplicationConfig replicationConfig, + String serviceID, ExcludeList excludeList, String clientMachine, + NetworkTopology clusterMap) throws IOException { + if (isAllocateBlockCacheEnabled) { + long readStartTime = Time.monotonicNowNanos(); + List<AllocatedBlock> allocatedBlocks = new ArrayList<>(); + ConcurrentLinkedDeque<ExpiringAllocatedBlock> queue = blockQueueMap.get(replicationConfig); + + // We redirect to the allocateBlock RPC call to SCM when we encounter an untested ReplicationConfig or a populated + // ExcludeList, otherwise we return blocks from cache. + if (queue != null && excludeList.isEmpty()) { + List<ExpiringAllocatedBlock> tempValidBlocks = new ArrayList<>(); + long now = System.currentTimeMillis(); + while (tempValidBlocks.size() < numBlocks) { + ExpiringAllocatedBlock expiringBlock = queue.poll(); + if (expiringBlock == null) { + break; + } + + if (now > expiringBlock.getExpiryTime()) { + continue; + } + + tempValidBlocks.add(expiringBlock); + } + + // If there aren't enough blocks in cache, we fallback to SCM. + if (tempValidBlocks.size() < numBlocks) { + List<AllocatedBlock> newBlocks = scmBlockLocationProtocol.allocateBlock(scmBlockSize, numBlocks, + replicationConfig, serviceID, excludeList, clientMachine); + allocatedBlocks.addAll(newBlocks); + + // Return unused valid blocks back to the front of the queue (preserving original order). + for (int i = tempValidBlocks.size() - 1; i >= 0; i--) { + queue.addFirst(tempValidBlocks.get(i)); + } + metrics.incrementCacheMisses(); + } else { + for (ExpiringAllocatedBlock expiringBlock : tempValidBlocks) { + AllocatedBlock block = expiringBlock.getBlock(); + List<DatanodeDetails> sortedNodes = + sortDatanodes(block.getPipeline().getNodes(), clientMachine, clusterMap); + if (!Objects.equals(sortedNodes, block.getPipeline().getNodesInOrder())) { + block = block.toBuilder() + .setPipeline(block.getPipeline().copyWithNodesInOrder(sortedNodes)) + .build(); + } + allocatedBlocks.add(block); + } + metrics.incrementCacheHits(); + } + + int queueSize = queue.size(); + if (queueSize < minBlocks) { + int blocksToPrefetch = maxBlocks - queueSize; + LOG.debug( + "Cache for {} is below threshold (size: {}, min: {}). Submitting async prefetch task for {} blocks.", + replicationConfig, queueSize, minBlocks, blocksToPrefetch); + submitPrefetchTask(scmBlockSize, blocksToPrefetch, replicationConfig, serviceID); + } + + metrics.addReadFromQueueLatency(Time.monotonicNowNanos() - readStartTime); + return allocatedBlocks; + + } else { + LOG.debug("Bypassing cache for {}. Reason: {}", replicationConfig, queue == null ? + "Unsupported replication config for caching." : "ExcludeList provided."); + metrics.addReadFromQueueLatency(Time.monotonicNowNanos() - readStartTime); + metrics.incrementCacheMisses(); + return scmBlockLocationProtocol.allocateBlock(scmBlockSize, numBlocks, replicationConfig, serviceID, + excludeList, clientMachine); + } + } else { + return scmBlockLocationProtocol.allocateBlock(scmBlockSize, numBlocks, replicationConfig, serviceID, excludeList, + clientMachine); + } + } + + private void submitPrefetchTask(long blockSize, int blocksToPrefetch, ReplicationConfig repConfig, String serviceID) { + + if (!isPrefetching.compareAndSet(false, true)) { + LOG.debug("Prefetch already in progress. Skipping new task for {}.", repConfig); + return; + } + + if (prefetchExecutor == null || prefetchExecutor.isShutdown()) { + LOG.warn("Async prefetch executor is not running or shutdown. Skipping prefetch task for {}.", repConfig); + return; + } + + prefetchExecutor.submit(() -> { + try { + List<AllocatedBlock> prefetchedBlocks = scmBlockLocationProtocol.allocateBlock(blockSize, blocksToPrefetch, + repConfig, serviceID, (ExcludeList) Collections.emptyList(), null); Review Comment: Added metrics for measuring prefetch blocks latency. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@ozone.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@ozone.apache.org For additional commands, e-mail: issues-h...@ozone.apache.org
