You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@flink.apache.org by "ASF GitHub Bot (JIRA)" <ji...@apache.org> on 2018/05/23 07:13:01 UTC
[jira] [Commented] (FLINK-6968) Store streaming, updating tables
with unique key in queryable state
[ https://issues.apache.org/jira/browse/FLINK-6968?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16486826#comment-16486826 ]
ASF GitHub Bot commented on FLINK-6968:
---------------------------------------
Github user twalthr commented on a diff in the pull request:
https://github.com/apache/flink/pull/5688#discussion_r190140171
--- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/sinks/QueryableTableSink.scala ---
@@ -0,0 +1,223 @@
+/*
+ * 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.flink.table.sinks
+
+import java.lang.{Boolean => JBool}
+
+import org.apache.flink.api.common.state.{ValueState, ValueStateDescriptor}
+import org.apache.flink.api.common.typeinfo.TypeInformation
+import org.apache.flink.api.java.functions.KeySelector
+import org.apache.flink.api.java.tuple.{Tuple2 => JTuple2}
+import org.apache.flink.api.java.typeutils.{ResultTypeQueryable, RowTypeInfo}
+import org.apache.flink.configuration.Configuration
+import org.apache.flink.streaming.api.datastream.DataStream
+import org.apache.flink.streaming.api.functions.KeyedProcessFunction
+import org.apache.flink.streaming.api.{TimeCharacteristic, TimeDomain}
+import org.apache.flink.table.api.StreamQueryConfig
+import org.apache.flink.table.runtime.aggregate.KeyedProcessFunctionWithCleanupState
+import org.apache.flink.types.Row
+import org.apache.flink.util.Collector
+
+/**
+ * A QueryableTableSink stores table in queryable state.
+ *
+ * This class stores table in queryable state so that users can access table data without
+ * dependency on external storage.
+ *
+ * Since this is only a kv storage, currently user can only do point query against it.
+ *
+ * Example:
+ * {{{
+ * val env = ExecutionEnvironment.getExecutionEnvironment
+ * val tEnv = TableEnvironment.getTableEnvironment(env)
+ *
+ * val table: Table = ...
+ *
+ * val queryableTableSink: QueryableTableSink = new QueryableTableSink(
+ * "prefix",
+ * queryConfig,
+ * None)
+ *
+ * tEnv.writeToSink(table, queryableTableSink, config)
+ * }}}
+ *
+ * When program starts to run, user can access state with QueryableStateClient.
+ * {{{
+ * val client = new QueryableStateClient(tmHostname, proxyPort)
+ * val data = client.getKvState(
+ * jobId,
+ * "prefix-column1",
+ * Row.of(1),
+ * new RowTypeInfo(Array(TypeInfoformation.of(classOf[Int]), Array("id"))
+ * stateDescriptor)
+ * .get();
+ *
+ * }}}
+ *
+ *
+ * @param namePrefix
+ * @param queryConfig
+ * @param cleanupTimeDomain
+ */
+class QueryableTableSink(
+ private val namePrefix: String,
+ private val queryConfig: StreamQueryConfig,
+ private val cleanupTimeDomain: Option[TimeDomain])
+ extends UpsertStreamTableSink[Row]
+ with TableSinkBase[JTuple2[JBool, Row]] {
+ private var keys: Array[String] = _
+
+ override def setKeyFields(keys: Array[String]): Unit = {
+ if (keys == null) {
+ throw new IllegalArgumentException("keys can't be null!")
+ }
+ this.keys = keys
+ }
+
+ override def setIsAppendOnly(isAppendOnly: JBool): Unit = {
+ if (isAppendOnly) {
+ throw new IllegalArgumentException("A QueryableTableSink can not be used with append-only " +
+ "tables as the table would grow infinitely")
+ }
+ }
+
+ override def getRecordType: TypeInformation[Row] = new RowTypeInfo(getFieldTypes, getFieldNames)
+
+ override def emitDataStream(dataStream: DataStream[JTuple2[JBool, Row]]): Unit = {
+ val keyIndices = keys.map(getFieldNames.indexOf(_))
+ val keyTypes = keyIndices.map(getFieldTypes(_))
+
+ val keySelectorType = new RowTypeInfo(keyTypes, keys)
+
+ val processFunction = new QueryableStateProcessFunction(
+ namePrefix,
+ queryConfig,
+ keys,
+ getFieldNames,
+ getFieldTypes,
+ calculateCleanupTimeDomain(dataStream.getExecutionEnvironment.getStreamTimeCharacteristic))
+
+ dataStream.keyBy(new RowKeySelector(keyIndices, keySelectorType))
+ .process(processFunction)
+ }
+
+ private def calculateCleanupTimeDomain(timeCharacteristic: TimeCharacteristic): TimeDomain = {
+ val timeDomainFromTimeCharacteristic = {
+ timeCharacteristic match {
+ case TimeCharacteristic.IngestionTime | TimeCharacteristic.ProcessingTime =>
+ TimeDomain.PROCESSING_TIME
+ case TimeCharacteristic.EventTime =>
+ TimeDomain.EVENT_TIME
+ }
+ }
+
+ cleanupTimeDomain.getOrElse(timeDomainFromTimeCharacteristic)
+ }
+
+ override protected def copy: TableSinkBase[JTuple2[JBool, Row]] = {
+ new QueryableTableSink(this.namePrefix, this.queryConfig, this.cleanupTimeDomain)
+ }
+}
+
+class RowKeySelector(
+ private val keyIndices: Array[Int],
+ @transient private val returnType: TypeInformation[Row])
+ extends KeySelector[JTuple2[JBool, Row], Row]
+ with ResultTypeQueryable[Row] {
+
+ override def getKey(value: JTuple2[JBool, Row]): Row = {
+ val keys = keyIndices
+
+ val srcRow = value.f1
+
+ val destRow = new Row(keys.length)
+ var i = 0
+ while (i < keys.length) {
+ destRow.setField(i, srcRow.getField(keys(i)))
+ i += 1
+ }
+
+ destRow
+ }
+
+ override def getProducedType: TypeInformation[Row] = returnType
+}
+
+class QueryableStateProcessFunction(
+ private val namePrefix: String,
+ private val queryConfig: StreamQueryConfig,
+ private val keyNames: Array[String],
+ private val fieldNames: Array[String],
+ private val fieldTypes: Array[TypeInformation[_]],
+ private val cleanupTimeDomain: TimeDomain)
+ extends KeyedProcessFunctionWithCleanupState[Row, JTuple2[JBool, Row], Void](queryConfig) {
+
+ @transient private var states = Array[ValueState[AnyRef]]()
--- End diff --
Use default initializer `_`.
> Store streaming, updating tables with unique key in queryable state
> -------------------------------------------------------------------
>
> Key: FLINK-6968
> URL: https://issues.apache.org/jira/browse/FLINK-6968
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: Renjie Liu
> Priority: Major
>
> Streaming tables with unique key are continuously updated. For example queries with a non-windowed aggregation generate such tables. Commonly, such updating tables are emitted via an upsert table sink to an external datastore (k-v store, database) to make it accessible to applications.
> This issue is about adding a feature to store and maintain such a table as queryable state in Flink. By storing the table in Flnk's queryable state, we do not need an external data store to access the results of the query but can query the results directly from Flink.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)