anishshri-db commented on code in PR #45932: URL: https://github.com/apache/spark/pull/45932#discussion_r1559866658
########## sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/ListStateImplWithTTL.scala: ########## @@ -0,0 +1,230 @@ +/* + * 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 + +import org.apache.spark.sql.Encoder +import org.apache.spark.sql.catalyst.encoders.ExpressionEncoder +import org.apache.spark.sql.execution.streaming.TransformWithStateKeyValueRowSchema.{KEY_ROW_SCHEMA, VALUE_ROW_SCHEMA_WITH_TTL} +import org.apache.spark.sql.execution.streaming.state.{NoPrefixKeyStateEncoderSpec, StateStore} +import org.apache.spark.sql.streaming.{ListState, TTLConfig} +import org.apache.spark.util.NextIterator + +/** + * Provides concrete implementation for list of values associated with a state variable + * used in the streaming transformWithState operator. + * + * @param store - reference to the StateStore instance to be used for storing state + * @param stateName - name of logical state partition + * @param keyEnc - Spark SQL encoder for key + * @param valEncoder - Spark SQL encoder for value + * @tparam S - data type of object that will be stored in the list + */ +class ListStateImplWithTTL[S]( + store: StateStore, + stateName: String, + keyExprEnc: ExpressionEncoder[Any], + valEncoder: Encoder[S], + ttlConfig: TTLConfig, + batchTimestampMs: Long) + extends SingleKeyTTLStateImpl(stateName, store, batchTimestampMs) with ListState[S] { + + private val keySerializer = keyExprEnc.createSerializer() + + private val stateTypesEncoder = StateTypesEncoder( + keySerializer, valEncoder, stateName, hasTtl = true) + + private val ttlExpirationMs = + StateTTL.calculateExpirationTimeForDuration(ttlConfig.ttlDuration, batchTimestampMs) + + private val listStatePutImpl = new ListStateModifyImpl[S]( + store, stateName, keyExprEnc, valEncoder, stateTypesEncoder.encodeValue(_, ttlExpirationMs)) + + initialize() + + private def initialize(): Unit = { + store.createColFamilyIfAbsent(stateName, KEY_ROW_SCHEMA, VALUE_ROW_SCHEMA_WITH_TTL, + NoPrefixKeyStateEncoderSpec(KEY_ROW_SCHEMA), useMultipleValuesPerKey = true) + } + /** Whether state exists or not. */ + override def exists(): Boolean = { + val encodedGroupingKey = stateTypesEncoder.encodeGroupingKey() + val stateValue = store.get(encodedGroupingKey, stateName) + stateValue != null + } + + /** + * Get the state value if it exists. If the state does not exist in state store, an + * empty iterator is returned. + */ + override def get(): Iterator[S] = { + val encodedKey = stateTypesEncoder.encodeGroupingKey() + val unsafeRowValuesIterator = store.valuesIterator(encodedKey, stateName) + + new NextIterator[S] { + + override protected def getNext(): S = { + unsafeRowValuesIterator.dropWhile { row => + stateTypesEncoder.isExpired(row, batchTimestampMs) + } + + if (unsafeRowValuesIterator.hasNext) { + val currentRow = unsafeRowValuesIterator.next() + if (!stateTypesEncoder.isExpired(currentRow, batchTimestampMs)) { + stateTypesEncoder.decodeValue(currentRow) + } else { + finished = true + null.asInstanceOf[S] + } + } else { + finished = true + null.asInstanceOf[S] + } + } + + override protected def close(): Unit = {} + } + } + + /** Update the value of the list. */ + override def put(newState: Array[S]): Unit = { + listStatePutImpl.put(newState) + upsertTTLForStateKey() + } + + /** Append an entry to the list. */ + override def appendValue(newState: S): Unit = { + listStatePutImpl.appendValue(newState) + upsertTTLForStateKey() + } + + /** Append an entire list to the existing value. */ + override def appendList(newState: Array[S]): Unit = { + listStatePutImpl.appendList(newState) + upsertTTLForStateKey() + } + + /** Remove this state. */ + override def clear(): Unit = { + listStatePutImpl.clear() + } + + /** + * + * Loops through all the values associated with the grouping key, and removes + * the expired elements from the list. + * @param groupingKey grouping key for which cleanup should be performed. + */ + override def clearIfExpired(groupingKey: Array[Byte]): Unit = { + val encodedGroupingKey = stateTypesEncoder.encodeSerializedGroupingKey(groupingKey) + val unsafeRowValuesIterator = store.valuesIterator(encodedGroupingKey, stateName) + // We clear the list, and use the iterator to put back all of the non-expired values + store.remove(encodedGroupingKey, stateName) + var isFirst = true + unsafeRowValuesIterator.foreach { encodedValue => + if (!stateTypesEncoder.isExpired(encodedValue, batchTimestampMs)) { + if (isFirst) { + store.put(encodedGroupingKey, encodedValue, stateName) + isFirst = false + } else { + store.merge(encodedGroupingKey, encodedValue, stateName) + } + } + } + } + + private def upsertTTLForStateKey(): Unit = { + val serializedGroupingKey = stateTypesEncoder.serializeGroupingKey() + upsertTTLForStateKey(ttlExpirationMs, serializedGroupingKey) + } + + /* + * Internal methods to probe state for testing. The below methods exist for unit tests + * to read the state ttl values, and ensure that values are persisted correctly in + * the underlying state store. + */ + + /** + * Retrieves the value from State even if its expired. This method is used + * in tests to read the state store value, and ensure if its cleaned up at the + * end of the micro-batch. + */ + private[sql] def getWithoutEnforcingTTL(): Iterator[S] = { + val encodedGroupingKey = stateTypesEncoder.encodeGroupingKey() + val unsafeRowValuesIterator = store.valuesIterator(encodedGroupingKey, stateName) + new Iterator[S] { + override def hasNext: Boolean = { Review Comment: Could we skip this ? -- 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. 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