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https://issues.apache.org/jira/browse/FLINK-6968?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16398019#comment-16398019
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ASF GitHub Bot commented on FLINK-6968:
---------------------------------------
Github user xccui commented on a diff in the pull request:
https://github.com/apache/flink/pull/5688#discussion_r174339296
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/sinks/QueryableTableSink.scala
---
@@ -0,0 +1,175 @@
+/*
+ * 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.ProcessFunction
+import org.apache.flink.table.api.StreamQueryConfig
+import
org.apache.flink.table.runtime.aggregate.ProcessFunctionWithCleanupState
+import org.apache.flink.types.Row
+import org.apache.flink.util.Collector
+import org.slf4j.LoggerFactory
+
+class QueryableTableSink(private val namePrefix: String,
+ private val queryConfig: StreamQueryConfig)
+ extends UpsertStreamTableSink[Row]
+ with TableSinkBase[JTuple2[JBool, Row]] {
+ private var keys: Array[String] = _
+
+ /**
+ * Configures the unique key fields of the [[Table]] to write.
+ * The method is called after [[TableSink.configure()]].
+ *
+ * The keys array might be empty, if the table consists of a single
(updated) record.
+ * If the table does not have a key and is append-only, the keys
attribute is null.
+ *
+ * @param keys the field names of the table's keys, an empty array if
the table has a single
+ * row, and null if the table is append-only and has no key.
+ */
+ override def setKeyFields(keys: Array[String]): Unit = {
+ if (keys == null) {
+ throw new IllegalArgumentException("keys can't be null!")
+ }
+ this.keys = keys
+ }
+
+ /**
+ * Specifies whether the [[Table]] to write is append-only or not.
+ *
+ * @param isAppendOnly true if the table is append-only, false
otherwise.
+ */
+ 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")
+ }
+ }
+
+ /** Returns the requested record type */
+ override def getRecordType: TypeInformation[Row] = new
RowTypeInfo(getFieldTypes, getFieldNames)
+
+ /** Emits the DataStream. */
+ 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)
+
+ dataStream.keyBy(new RowKeySelector(keyIndices, keySelectorType))
+ .process(processFunction)
+ }
+
+ /** Return a deep copy of the [[TableSink]]. */
+ override protected def copy: TableSinkBase[JTuple2[JBool, Row]] = {
--- End diff --
The docs for overridden methods could be omitted.
> 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.
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