satishd commented on code in PR #11390: URL: https://github.com/apache/kafka/pull/11390#discussion_r1034340498
########## core/src/main/scala/kafka/log/remote/RemoteIndexCache.scala: ########## @@ -0,0 +1,284 @@ +/** + * 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 kafka.log.remote + +import kafka.log.{LazyIndex, _} +import kafka.log.remote.RemoteIndexCache.DirName +import kafka.utils.{CoreUtils, Logging, ShutdownableThread} +import org.apache.kafka.common.Uuid +import org.apache.kafka.common.errors.CorruptRecordException +import org.apache.kafka.common.utils.Utils +import org.apache.kafka.server.log.remote.storage.RemoteStorageManager.IndexType +import org.apache.kafka.server.log.remote.storage.{RemoteLogSegmentMetadata, RemoteStorageManager} + +import java.io.{File, InputStream} +import java.nio.file.{Files, Path} +import java.util +import java.util.concurrent.LinkedBlockingQueue +import java.util.concurrent.locks.ReentrantReadWriteLock + +object RemoteIndexCache { + val DirName = "remote-log-index-cache" + val TmpFileSuffix = ".tmp" +} + +class Entry(val offsetIndex: LazyIndex[OffsetIndex], val timeIndex: LazyIndex[TimeIndex], val txnIndex: TransactionIndex) { + private var markedForCleanup: Boolean = false + private val lock: ReentrantReadWriteLock = new ReentrantReadWriteLock() + + def lookupOffset(targetOffset: Long): OffsetPosition = { + CoreUtils.inLock(lock.readLock()) { + if (markedForCleanup) throw new IllegalStateException("This entry is marked for cleanup") + else offsetIndex.get.lookup(targetOffset) + } + } + + def lookupTimestamp(timestamp: Long, startingOffset: Long): OffsetPosition = { + CoreUtils.inLock(lock.readLock()) { + if (markedForCleanup) throw new IllegalStateException("This entry is marked for cleanup") + + val timestampOffset = timeIndex.get.lookup(timestamp) + offsetIndex.get.lookup(math.max(startingOffset, timestampOffset.offset)) + } + } + + def markForCleanup(): Unit = { + CoreUtils.inLock(lock.writeLock()) { + if (!markedForCleanup) { + markedForCleanup = true + Array(offsetIndex, timeIndex).foreach(index => + index.renameTo(new File(CoreUtils.replaceSuffix(index.file.getPath, "", UnifiedLog.DeletedFileSuffix)))) + txnIndex.renameTo(new File(CoreUtils.replaceSuffix(txnIndex.file.getPath, "", + UnifiedLog.DeletedFileSuffix))) + } + } + } + + def cleanup(): Unit = { + markForCleanup() + CoreUtils.tryAll(Seq(() => offsetIndex.deleteIfExists(), () => timeIndex.deleteIfExists(), () => txnIndex.deleteIfExists())) + } + + def close(): Unit = { + Array(offsetIndex, timeIndex).foreach(index => try { + index.close() + } catch { + case _: Exception => // ignore error. + }) + Utils.closeQuietly(txnIndex, "Closing the transaction index.") + } +} + +/** + * This is a LRU cache of remote index files stored in `$logdir/remote-log-index-cache`. This is helpful to avoid + * re-fetching the index files like offset, time indexes from the remote storage for every fetch call. + * + * @param maxSize + * @param remoteStorageManager + * @param logDir + */ +//todo-tier make maxSize configurable +class RemoteIndexCache(maxSize: Int = 1024, remoteStorageManager: RemoteStorageManager, logDir: String) extends Logging { + + val cacheDir = new File(logDir, DirName) + @volatile var closed = false + + val expiredIndexes = new LinkedBlockingQueue[Entry]() + val lock = new Object() + + val entries: util.Map[Uuid, Entry] = new java.util.LinkedHashMap[Uuid, Entry](maxSize / 2, + 0.75f, true) { + override def removeEldestEntry(eldest: util.Map.Entry[Uuid, Entry]): Boolean = { + if (this.size() > maxSize) { + val entry = eldest.getValue + // Mark the entries for cleanup, background thread will clean them later. + entry.markForCleanup() + expiredIndexes.add(entry) + true + } else { + false + } + } + } + + private def init(): Unit = { + if (cacheDir.mkdir()) + info(s"Created $cacheDir successfully") + + // Delete any .deleted files remained from the earlier run of the broker. + Files.list(cacheDir.toPath).forEach((path: Path) => { + if (path.endsWith(UnifiedLog.DeletedFileSuffix)) { + Files.deleteIfExists(path) + } + }) + + Files.list(cacheDir.toPath).forEach((path:Path) => { + val pathStr = path.getFileName.toString + val name = pathStr.substring(0, pathStr.lastIndexOf("_") + 1) + + // Create entries for each path if all the index files exist. + val firstIndex = name.indexOf('_') + val offset = name.substring(0, firstIndex).toInt + val uuid = Uuid.fromString(name.substring(firstIndex + 1, name.lastIndexOf('_'))) + + if(!entries.containsKey(uuid)) { + val offsetIndexFile = new File(cacheDir, name + UnifiedLog.IndexFileSuffix) + val timestampIndexFile = new File(cacheDir, name + UnifiedLog.TimeIndexFileSuffix) + val txnIndexFile = new File(cacheDir, name + UnifiedLog.TxnIndexFileSuffix) + + if (offsetIndexFile.exists() && timestampIndexFile.exists() && txnIndexFile.exists()) { + + val offsetIndex: LazyIndex[OffsetIndex] = { + val index = LazyIndex.forOffset(offsetIndexFile, offset, Int.MaxValue, writable = false) + index.get.sanityCheck() + index + } + + val timeIndex: LazyIndex[TimeIndex] = { + val index = LazyIndex.forTime(timestampIndexFile, offset, Int.MaxValue, writable = false) + index.get.sanityCheck() + index + } + + val txnIndex: TransactionIndex = { + val index = new TransactionIndex(offset, txnIndexFile) + index.sanityCheck() + index + } + + val entry = new Entry(offsetIndex, timeIndex, txnIndex) + entries.put(uuid, entry) + } else { + // Delete all of them if any one of those indexes is not available for a specific segment id + Files.deleteIfExists(offsetIndexFile.toPath) + Files.deleteIfExists(timestampIndexFile.toPath) + Files.deleteIfExists(txnIndexFile.toPath) + } + } + }) + } + + init() + + // Start cleaner thread that will clean the expired entries + val cleanerThread: ShutdownableThread = new ShutdownableThread("remote-log-index-cleaner") { + setDaemon(true) + + override def doWork(): Unit = { + while (!closed) { + try { + val entry = expiredIndexes.take() + info(s"Cleaning up index entry $entry") + entry.cleanup() + } catch { + case ex: InterruptedException => info("Cleaner thread was interrupted", ex) + case ex: Exception => error("Error occurred while fetching/cleaning up expired entry", ex) + } + } + } + } + cleanerThread.start() + + def getIndexEntry(remoteLogSegmentMetadata: RemoteLogSegmentMetadata): Entry = { + def loadIndexFile[T](fileName: String, + suffix: String, + fetchRemoteIndex: RemoteLogSegmentMetadata => InputStream, + readIndex: File => T): T = { + val indexFile = new File(cacheDir, fileName + suffix) + + def fetchAndCreateIndex(): T = { + val tmpIndexFile = new File(cacheDir, fileName + suffix + RemoteIndexCache.TmpFileSuffix) + + val inputStream = fetchRemoteIndex(remoteLogSegmentMetadata) + try { + Files.copy(inputStream, tmpIndexFile.toPath) + } finally { + if (inputStream != null) { + inputStream.close() + } + } + + Utils.atomicMoveWithFallback(tmpIndexFile.toPath, indexFile.toPath, false) + readIndex(indexFile) + } + + if (indexFile.exists()) { + try { + readIndex(indexFile) + } catch { + case ex: CorruptRecordException => + info("Error occurred while loading the stored index", ex) + fetchAndCreateIndex() + } + } else { + fetchAndCreateIndex() + } + } + + lock synchronized { + entries.computeIfAbsent(remoteLogSegmentMetadata.remoteLogSegmentId().id(), (uuid: Uuid) => { Review Comment: https://issues.apache.org/jira/browse/KAFKA-13560 covers to get indexes or data in async manner for critical paths, we can cover as part of that JIRA. wdyt? -- This is an automated message from the Apache Git Service. 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