gaborgsomogyi commented on a change in pull request #24922: [SPARK-28120][SS] Rocksdb state storage implementation URL: https://github.com/apache/spark/pull/24922#discussion_r316167162
########## File path: sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/RocksDbStateStoreProvider.scala ########## @@ -0,0 +1,642 @@ +/* + * 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 scala.collection.JavaConverters._ +import scala.util.control.NonFatal + +import org.apache.commons.io.FileUtils +import org.apache.hadoop.conf.Configuration +import org.apache.hadoop.fs._ + +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 + + /* + * numEntriesInDb and bytesUsedByDb are estimated value + * due to the nature of RocksDB implementation. + * see https://github.com/facebook/rocksdb/wiki/RocksDB-FAQ for more details + */ + 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, + rocksDbConf) + rocksDbWriteInstance.open(rocksDbPath) + 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"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) + 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"Cannot commit after already committed or aborted") + try { + synchronized { + rocksDbWriteInstance.commit(Some(getCheckpointPath(newVersion))) + finalizeDeltaFile(compressedStream) + } + state = COMMITTED + numEntriesInDb = rocksDbWriteInstance.getApproxEntriesInDb() + 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 = getCheckpointPath(version) + val r: RocksDbInstance = + new RocksDbInstance(keySchema, valueSchema, version.toString, rocksDbConf) + r.open(path, readOnly = true) + r.iterator(closeDbOnCompletion = true) + } + case COMMITTED => + logDebug(s"state = committed using check-pointed DB with version $newVersion") + // use check-pointed db for current updated version + val path = getCheckpointPath(newVersion) + val r: RocksDbInstance = + new RocksDbInstance(keySchema, valueSchema, newVersion.toString, rocksDbConf) + r.open(path, readOnly = true) + r.iterator(closeDbOnCompletion = true) + + case _ => Iterator.empty + } + } + + override def metrics: StateStoreMetrics = { + val metricsFromProvider: Map[String, Long] = getMetricsForProvider() + val customMetrics = metricsFromProvider.flatMap { + case (name, value) => + // just allow searching from list cause the list is small enough + supportedCustomMetrics.find(_.name == name).map(_ -> value) + } + StateStoreMetrics(Math.max(numEntriesInDb, 0), Math.max(bytesUsedByDb, 0), customMetrics) + } + + /* + * Whether all updates have been committed + */ + override def hasCommitted: Boolean = { + state == COMMITTED + } + + override def toString(): String = { + s"RocksDbStateStore[id=(op=${id.operatorId},part=${id.partitionId}),dir=$baseDir]" + } + + } + + /* + * Initialize the provider 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 + 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), Review comment: Since RocksDb would be a built-in store provider we need to use `ConfigBuilder`? 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