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Posted to reviews@spark.apache.org by GitBox <gi...@apache.org> on 2019/07/01 00:56:27 UTC
[GitHub] [spark] HeartSaVioR commented on a change in pull request #24922:
[SPARK-28120][SS] Rocksdb state storage implementation
HeartSaVioR commented on a change in pull request #24922: [SPARK-28120][SS] Rocksdb state storage implementation
URL: https://github.com/apache/spark/pull/24922#discussion_r298857349
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File path: sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/RocksDbStateStoreProvider.scala
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+/*
+ * 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.spark.sql.execution.streaming.state;
+
+import java.io._
+import java.util
+import java.util.Locale
+
+import org.apache.commons.io.FileUtils
+import org.apache.hadoop.conf.Configuration
+import org.apache.hadoop.fs._
+import scala.collection.JavaConverters._
+import scala.util.control.NonFatal
+
+import org.apache.spark.{SparkConf, SparkEnv}
+import org.apache.spark.internal.Logging
+import org.apache.spark.io.FileUtility
+import org.apache.spark.sql.catalyst.expressions.UnsafeRow
+import org.apache.spark.sql.execution.streaming.CheckpointFileManager
+import org.apache.spark.sql.types.StructType
+import org.apache.spark.util.Utils
+
+private[sql] class RocksDbStateStoreProvider extends StateStoreProvider with Logging {
+
+ /* Internal fields and methods */
+ @volatile private var stateStoreId_ : StateStoreId = _
+ @volatile private var keySchema: StructType = _
+ @volatile private var valueSchema: StructType = _
+ @volatile private var storeConf: StateStoreConf = _
+ @volatile private var hadoopConf: Configuration = _
+ @volatile private var numberOfVersionsToRetain: Int = _
+ @volatile private var localDirectory: String = _
+
+ /*
+ * Additional configurations related to rocksDb. This will capture all configs in
+ * SQLConf that start with `spark.sql.streaming.stateStore.rocksDb`
+ */
+ @volatile private var rocksDbConf: Map[String, String] = Map.empty[String, String]
+
+ private lazy val baseDir: Path = stateStoreId.storeCheckpointLocation()
+ private lazy val fm = CheckpointFileManager.create(baseDir, hadoopConf)
+ private lazy val sparkConf = Option(SparkEnv.get).map(_.conf).getOrElse(new SparkConf)
+ private case class StoreFile(version: Long, path: Path, isSnapshot: Boolean)
+
+ import WALUtils._
+
+ /** Implementation of [[StateStore]] API which is backed by RocksDb and HDFS */
+ class RocksDbStateStore(val version: Long) extends StateStore with Logging {
+
+ /** Trait and classes representing the internal state of the store */
+ trait STATE
+ case object LOADED extends STATE
+ case object UPDATING extends STATE
+ case object COMMITTED extends STATE
+ case object ABORTED extends STATE
+
+ private val newVersion = version + 1
+ @volatile private var state: STATE = LOADED
+ private val finalDeltaFile: Path = deltaFile(baseDir, newVersion)
+ private lazy val deltaFileStream = fm.createAtomic(finalDeltaFile, overwriteIfPossible = true)
+ private lazy val compressedStream = compressStream(deltaFileStream, sparkConf)
+
+ override def id: StateStoreId = RocksDbStateStoreProvider.this.stateStoreId
+
+ var rocksDbWriteInstance: OptimisticTransactionDbInstance = null
+ var numEntriesInDb: Long = 0L
+ var bytesUsedByDb: Long = 0L
+
+ private def initTransaction(): Unit = {
+ if (state == LOADED && rocksDbWriteInstance == null) {
+ logDebug(s"Creating Transactional DB for batch $version")
+ rocksDbWriteInstance =
+ new OptimisticTransactionDbInstance(keySchema, valueSchema, newVersion.toString)
+ rocksDbWriteInstance.open(rocksDbPath, rocksDbConf)
+ state = UPDATING
+ rocksDbWriteInstance.startTransactions()
+ }
+ }
+
+ override def get(key: UnsafeRow): UnsafeRow = {
+ initTransaction
+ rocksDbWriteInstance.get(key)
+ }
+
+ override def put(key: UnsafeRow, value: UnsafeRow): Unit = {
+ initTransaction
+ verify(
+ state == UPDATING,
+ s"Current state of the store is $state. " +
+ s"Cannot put after already committed or aborted")
+ val keyCopy = key.copy()
+ val valueCopy = value.copy()
+ rocksDbWriteInstance.put(keyCopy, valueCopy)
+ writeUpdateToDeltaFile(compressedStream, keyCopy, valueCopy)
+ }
+
+ override def remove(key: UnsafeRow): Unit = {
+ initTransaction
+ verify(state == UPDATING, "Cannot remove after already committed or aborted")
+ rocksDbWriteInstance.remove(key)
+ // TODO check if removed value is null
+ writeRemoveToDeltaFile(compressedStream, key)
+ }
+
+ override def getRange(
+ start: Option[UnsafeRow],
+ end: Option[UnsafeRow]): Iterator[UnsafeRowPair] = {
+ verify(state == UPDATING, "Cannot getRange after already committed or aborted")
+ iterator()
+ }
+
+ /** Commit all the updates that have been made to the store, and return the new version. */
+ override def commit(): Long = {
+ initTransaction
+ verify(
+ state == UPDATING,
+ s"Current state of the store is $state " +
+ s"Cannot commit after already committed or aborted")
+ try {
+ state = COMMITTED
+ synchronized {
+ rocksDbWriteInstance.commit(Some(getBackupPath(newVersion)))
+ finalizeDeltaFile(compressedStream)
+ }
+ numEntriesInDb = rocksDbWriteInstance.otdb.getLongProperty("rocksdb.estimate-num-keys")
+ bytesUsedByDb = numEntriesInDb * (keySchema.defaultSize + valueSchema.defaultSize)
+ newVersion
+ } catch {
+ case NonFatal(e) =>
+ throw new IllegalStateException(s"Error committing version $newVersion into $this", e)
+ } finally {
+ storeMap.remove(version)
+ close()
+ }
+ }
+
+ /*
+ * Abort all the updates made on this store. This store will not be usable any more.
+ */
+ override def abort(): Unit = {
+ // This if statement is to ensure that files are deleted only if there are changes to the
+ // StateStore. We have two StateStores for each task, one which is used only for reading, and
+ // the other used for read+write. We don't want the read-only to delete state files.
+ try {
+ if (state == UPDATING) {
+ state = ABORTED
+ synchronized {
+ rocksDbWriteInstance.abort()
+ cancelDeltaFile(compressedStream, deltaFileStream)
+ }
+ logInfo(s"Aborted version $newVersion for $this")
+ } else {
+ state = ABORTED
+ }
+ } catch {
+ case NonFatal(e) =>
+ throw new IllegalStateException(s"Error aborting version $newVersion into $this", e)
+ } finally {
+ storeMap.remove(version)
+ close()
+ }
+ }
+
+ def close(): Unit = {
+ if (rocksDbWriteInstance != null) {
+ rocksDbWriteInstance.close()
+ rocksDbWriteInstance = null
+ }
+ }
+
+ /*
+ * Get an iterator of all the store data.
+ * This can be called only after committing all the updates made in the current thread.
+ */
+ override def iterator(): Iterator[UnsafeRowPair] = {
+ state match {
+ case UPDATING =>
+ logDebug("state = updating using transaction DB")
+ // We need to use current db to read uncommitted transactions
+ rocksDbWriteInstance.iterator(closeDbOnCompletion = false)
+
+ case LOADED | ABORTED =>
+ // use check-pointed db for previous version
+ logDebug(s"state = loaded/aborted using check-pointed DB with version $version")
+ if (version == 0) {
+ Iterator.empty
+ } else {
+ val path = getBackupPath(version)
+ val r: RocksDbInstance = new RocksDbInstance(keySchema, valueSchema, version.toString)
+ r.open(path, rocksDbConf, readOnly = true)
+ r.iterator(closeDbOnCompletion = true)
+ }
+ case COMMITTED =>
+ logDebug(s"state = committed using check-pointed DB with version $newVersion")
+ // use check-pointed db for current updated version
+ val path = getBackupPath(newVersion)
+ val r: RocksDbInstance =
+ new RocksDbInstance(keySchema, valueSchema, newVersion.toString)
+ r.open(path, rocksDbConf, readOnly = true)
+ r.iterator(closeDbOnCompletion = true)
+
+ case _ => Iterator.empty
+ }
+ }
+
+ override def metrics: StateStoreMetrics = {
+ val metricsFromProvider: Map[String, Long] = getMetricsForProvider()
+ val customMetrics = metricsFromProvider.flatMap {
+ case (name, value) =>
+ // just allow searching from list cause the list is small enough
+ supportedCustomMetrics.find(_.name == name).map(_ -> value)
+ }
+ return StateStoreMetrics(
+ Math.max(numEntriesInDb, 0),
+ Math.max(bytesUsedByDb, 0),
+ customMetrics)
+ }
+
+ /*
+ * Whether all updates have been committed
+ */
+ override def hasCommitted: Boolean = {
+ state == COMMITTED
+ }
+
+ override def toString(): String = {
+ s"RocksDbStateStore[id=(op=${id.operatorId},part=${id.partitionId}),dir=$baseDir]"
+ }
+
+ }
+
+ /*
+ * Initialize the provide with more contextual information from the SQL operator.
+ * This method will be called first after creating an instance of the StateStoreProvider by
+ * reflection.
+ *
+ * @param stateStoreId Id of the versioned StateStores that this provider will generate
+ * @param keySchema Schema of keys to be stored
+ * @param valueSchema Schema of value to be stored
+ * @param keyIndexOrdinal Optional column (represent as the ordinal of the field in keySchema) by
+ * which the StateStore implementation could index the data.
+ * @param storeConfs Configurations used by the StateStores
+ * @param hadoopConf Hadoop configuration that could be used by StateStore
+ * to save state data
+ */
+ override def init(
+ stateStoreId: StateStoreId,
+ keySchema: StructType,
+ valueSchema: StructType,
+ keyIndexOrdinal: Option[Int], // for sorting the data by their keys
+ storeConfs: StateStoreConf,
+ hadoopConf: Configuration): Unit = {
+ this.stateStoreId_ = stateStoreId
+ this.keySchema = keySchema
+ this.valueSchema = valueSchema
+ this.storeConf = storeConfs
+ this.hadoopConf = hadoopConf
+ // TODO add new conf for `maxVersionsToRetainInMemory`
+ this.numberOfVersionsToRetain = storeConfs.maxVersionsToRetainInMemory
+ fm.mkdirs(baseDir)
+ this.rocksDbConf = storeConf.confs
+ .filter(_._1.startsWith("spark.sql.streaming.stateStore.rocksDb"))
+ .map {
+ case (k, v) => (k.toLowerCase(Locale.ROOT), v)
+ }
+ this.localDirectory = this.rocksDbConf
+ .getOrElse(
+ "spark.sql.streaming.stateStore.rocksDb.localDirectory".toLowerCase(Locale.ROOT),
+ RocksDbStateStoreProvider.ROCKS_DB_BASE_PATH)
+ }
+
+ /*
+ * Return the id of the StateStores this provider will generate.
+ * Should be the same as the one passed in init().
+ */
+ override def stateStoreId: StateStoreId = stateStoreId_
+
+ /*
+ * Called when the provider instance is unloaded from the executor
+ */
+ override def close(): Unit = {
+ storeMap.values.asScala.foreach(_.close)
+ storeMap.clear()
+ }
+
+ private val storeMap = new util.HashMap[Long, RocksDbStateStore]()
+
+ /*
+ * Optional custom metrics that the implementation may want to report.
+ *
+ * @note The StateStore objects created by this provider must report the same custom metrics
+ * (specifically, same names) through `StateStore.metrics`.
+ */
+ // TODO
+ override def supportedCustomMetrics: Seq[StateStoreCustomMetric] = {
+ Nil
+ }
+
+ override def toString(): String = {
+ s"RocksDbStateStoreProvider[" +
+ s"id = (op=${stateStoreId.operatorId},part=${stateStoreId.partitionId}),dir = $baseDir]"
+ }
+
+ def getMetricsForProvider(): Map[String, Long] = synchronized {
+ Map.empty[String, Long]
+ }
+
+ /*
+ * Return an instance of [[StateStore]] representing state data of the given version
+ */
+ override def getStore(version: Long): StateStore = synchronized {
+ logInfo(s"get Store for version $version")
+ require(version >= 0, "Version cannot be less than 0")
+ if (storeMap.containsKey(version)) {
+ storeMap.get(version)
+ } else {
+ val store = createStore(version)
+ storeMap.put(version, store)
+ store
+ }
+ }
+
+ def createStore(version: Long): RocksDbStateStore = {
+ val newStore = new RocksDbStateStore(version)
+ logInfo(
+ s"Creating a new Store for version $version and partition ${stateStoreId_.partitionId}")
+ if (version > 0 & !checkIfStateExists(version)) {
+ // load the data in the rocksDB
+ logInfo(s"Loading state for $version and partition ${stateStoreId_.partitionId}")
+ loadState(version)
+ }
+ newStore
+ }
+
+ def checkIfStateExists(version: Long): Boolean = {
+ val dbPath: Path = new Path(rocksDbPath, version.toString.toUpperCase(Locale.ROOT))
+ val f: File = new File(dbPath.toString)
+ f.exists()
+ }
+
+ def loadState(version: Long): Unit = {
+ // search for state on snapshot
+ var rocksDbWriteInstance: OptimisticTransactionDbInstance = null
+ var lastAvailableVersion = version
+ var found = false
+ val (result, elapsedMs) = Utils.timeTakenMs {
+ try {
+ if (checkIfStateExists(version - 1)) {
+ found = true
+ lastAvailableVersion = version - 1
+ } else {
+ // Destroy DB so that we can recontruct it using snapshot and delta files
+ RocksDbInstance.destroyDB(rocksDbPath)
+ }
+
+ // Check for snapshot files starting from "version"
+ while (!found && lastAvailableVersion > 0) {
+ found = {
+ try {
+ loadSnapshotFile(lastAvailableVersion)
+ } catch {
+ case e: Exception =>
+ logError(s"$e while reading snapshot file")
+ throw e
+ }
+ }
+ if (!found) {
+ lastAvailableVersion = lastAvailableVersion - 1
+ }
+ logInfo(
+ s"Snapshot for $lastAvailableVersion for " +
+ s"partition ${stateStoreId_.partitionId} found = $found")
+ }
+
+ rocksDbWriteInstance =
+ new OptimisticTransactionDbInstance(keySchema, valueSchema, version.toString)
+ rocksDbWriteInstance.open(rocksDbPath, rocksDbConf)
+ rocksDbWriteInstance.startTransactions()
+
+ // Load all the deltas from the version after the last available
+ // one up to the target version.
+ // The last available version is the one with a full snapshot, so it doesn't need deltas.
+ for (deltaVersion <- (lastAvailableVersion + 1) to version) {
+ val fileToRead = deltaFile(baseDir, deltaVersion)
+ updateFromDeltaFile(
+ fm,
+ fileToRead,
+ keySchema,
+ valueSchema,
+ rocksDbWriteInstance,
+ sparkConf)
+ logInfo(s"Read delta file for version $version of $this from $fileToRead")
+ }
+
+ rocksDbWriteInstance.commit(Some(getBackupPath(version)))
+ rocksDbWriteInstance.close()
+ rocksDbWriteInstance = null
+ } catch {
+ case e: IllegalStateException =>
+ logError(s"Exception while loading state ${e.getMessage}")
+ if (rocksDbWriteInstance != null) {
+ rocksDbWriteInstance.abort()
+ rocksDbWriteInstance.close()
+ }
+ throw e
+ }
+ }
+ logInfo(s"Loading state for $version takes $elapsedMs ms.")
+ }
+
+ private def loadSnapshotFile(version: Long): Boolean = {
+ val fileToRead = snapshotFile(baseDir, version)
+ val tmpLocDir: File = new File(getTempPath(version))
+ val tmpLocFile: File = new File(getTempPath(version).concat(".tar"))
+ try {
+ if (!fm.exists(fileToRead)) {
+ return false
+ }
+ logInfo(s"Will download $fileToRead at location ${tmpLocFile.toString()}")
+ if (downloadFile(fm, fileToRead, new Path(tmpLocFile.getAbsolutePath), sparkConf)) {
+ FileUtility.unTar(tmpLocFile)
+ if (!tmpLocDir.list().exists(_.endsWith(".sst"))) {
+ logWarning("Snaphot files are corrupted")
+ throw new IOException(
+ s"Error reading snapshot file $fileToRead of $this:" +
+ s" No SST files found")
+ }
+ FileUtils.moveDirectory(tmpLocDir, new File(rocksDbPath))
+ return true
+ }
+ } catch {
+ case e: Exception =>
+ logError(s"Exception while loading snapshot file $e")
+ throw e
+ } finally {
+ if (tmpLocFile.exists()) {
+ tmpLocFile.delete()
+ }
+ FileUtils.deleteDirectory(tmpLocDir)
+ }
+ return false
+ }
+
+ /** Optional method for providers to allow for background maintenance (e.g. compactions) */
+ override def doMaintenance(): Unit = {
+ try {
+ val (files: Seq[WALUtils.StoreFile], e1) = Utils.timeTakenMs(fetchFiles(fm, baseDir))
+ logDebug(s"fetchFiles() took $e1 ms.")
+ doSnapshot(files)
+ cleanup(files)
+ cleanRocksDBBackupInstances(files)
+ } catch {
+ case NonFatal(e) =>
+ logWarning(s"Error performing snapshot and cleaning up $this")
+ }
+ }
+
+ private def doSnapshot(files: Seq[WALUtils.StoreFile]): Unit = {
+ if (files.nonEmpty) {
+ val lastVersion = files.last.version
+ val deltaFilesForLastVersion =
+ filesForVersion(files, lastVersion).filter(_.isSnapshot == false)
+ if (deltaFilesForLastVersion.size > storeConf.minDeltasForSnapshot) {
+ val dbPath = getBackupPath(lastVersion)
+ val snapShotFileName = getTempPath(lastVersion).concat(".snapshot")
+ val f = new File(snapShotFileName)
+ f.delete() // delete any existing tarball
+ try {
+ val (_, t1) = Utils.timeTakenMs {
+ FileUtility.createTarFile(dbPath, snapShotFileName)
+ val targetFile = snapshotFile(baseDir, lastVersion)
+ uploadFile(fm, new Path(snapShotFileName), targetFile, sparkConf)
+ }
+ logInfo(
+ s"Creating snapshot file for" +
+ s" ${stateStoreId_.partitionId} took $t1 ms.")
+ } catch {
+ case e: Exception =>
+ logError(s"Exception while creating snapshot $e} ")
+ throw e
+ } finally {
+ f.delete() // delete the tarball
+ }
+ }
+ }
+ }
+
+ /*
+ * Clean up old snapshots and delta files that are not needed any more. It ensures that last
+ * few versions of the store can be recovered from the files, so re-executed RDD operations
+ * can re-apply updates on the past versions of the store.
+ */
+ private[state] def cleanup(files: Seq[WALUtils.StoreFile]): Unit = {
+ try {
+ if (files.nonEmpty) {
+ val earliestVersionToRetain = files.last.version - storeConf.minVersionsToRetain
+ if (earliestVersionToRetain > 0) {
+ val earliestFileToRetain = filesForVersion(files, earliestVersionToRetain).head
+ val filesToDelete = files.filter(_.version < earliestFileToRetain.version)
+ val (_, e2) = Utils.timeTakenMs {
+ filesToDelete.foreach { f =>
+ fm.delete(f.path)
+ val file = new File(rocksDbPath, f.version.toString.toUpperCase(Locale.ROOT))
+ if (file.exists()) {
+ file.delete()
+ }
+ }
+ }
+ logDebug(s"deleting files took $e2 ms.")
+ logInfo(
+ s"Deleted files older than ${earliestFileToRetain.version} for $this: " +
+ filesToDelete.mkString(", "))
+ }
+ }
+ } catch {
+ case NonFatal(e) =>
+ logWarning(s"Error cleaning up files for $this", e)
+ }
+ }
+
+ private def cleanRocksDBBackupInstances(files: Seq[WALUtils.StoreFile]): Unit = {
+ try {
+ if (files.nonEmpty) {
+ val earliestVersionToRetain = files.last.version - storeConf.minVersionsToRetain
+ if (earliestVersionToRetain > 0) {
+ for (v <- (earliestVersionToRetain - 1) to 1) {
+ // Destroy the backup path
+ logDebug((s"Destroying backup version = $v"))
+ RocksDbInstance.destroyDB(getBackupPath(v))
+ }
+ }
+ }
+ } catch {
+ case NonFatal(e) => logWarning(s"Error cleaning up files for $this", e)
+ }
+ }
+
+ // Used only for unit tests
+ private[sql] def latestIterator(): Iterator[UnsafeRowPair] = synchronized {
+ val versionsInFiles = fetchFiles(fm, baseDir).map(_.version).toSet
+ var itr = Iterator.empty
+ if (versionsInFiles.nonEmpty) {
+ val maxVersion = versionsInFiles.max
+ if (maxVersion == 0) {
+ return Iterator.empty
+ }
+ // FIXME assuming maxVersion exists in rocksDB
Review comment:
Please address this sooner - either fail the query or do workaround. Let's not leave this as undefined behavior.
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