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https://issues.apache.org/jira/browse/FLINK-9513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16520552#comment-16520552
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ASF GitHub Bot commented on FLINK-9513:
---------------------------------------
Github user azagrebin commented on a diff in the pull request:
https://github.com/apache/flink/pull/6196#discussion_r197498439
--- Diff:
flink-runtime/src/main/java/org/apache/flink/runtime/state/ttl/TtlStateFactory.java
---
@@ -0,0 +1,207 @@
+/*
+ * 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.runtime.state.ttl;
+
+import org.apache.flink.api.common.state.AggregatingStateDescriptor;
+import org.apache.flink.api.common.state.FoldingStateDescriptor;
+import org.apache.flink.api.common.state.ListStateDescriptor;
+import org.apache.flink.api.common.state.MapStateDescriptor;
+import org.apache.flink.api.common.state.ReducingStateDescriptor;
+import org.apache.flink.api.common.state.State;
+import org.apache.flink.api.common.state.StateDescriptor;
+import org.apache.flink.api.common.state.ValueStateDescriptor;
+import org.apache.flink.api.common.typeutils.CompositeSerializer;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.common.typeutils.base.LongSerializer;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.runtime.state.KeyedStateFactory;
+import org.apache.flink.util.FlinkRuntimeException;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+/**
+ * This state factory wraps state objects, produced by backends, with TTL
logic.
+ */
+public class TtlStateFactory {
+ public static <N, SV, S extends State, IS extends S> IS
createStateAndWrapWithTtlIfEnabled(
+ TypeSerializer<N> namespaceSerializer,
+ StateDescriptor<S, SV> stateDesc,
+ KeyedStateFactory originalStateFactory,
+ TtlConfig ttlConfig,
+ TtlTimeProvider timeProvider) throws Exception {
+ return ttlConfig.getTtlUpdateType() == TtlUpdateType.Disabled ?
+ originalStateFactory.createState(namespaceSerializer,
stateDesc) :
+ new TtlStateFactory(originalStateFactory, ttlConfig,
timeProvider)
+ .createState(namespaceSerializer, stateDesc);
+ }
+
+ private final Map<Class<? extends StateDescriptor>, StateFactory>
stateFactories;
--- End diff --
It could be static. The idea was to create `TtlStateFactory` object for
each call of `createStateAndWrapWithTtlIfEnabled`. I think creating of state
object will not happen often, only at init. The object contains non static
references to originalStateFactory, ttlConfig, timeProvider to make
`createXxxState` methods less verbose. `stateFactories` contains reference to
this object in `createStateFactories`, so it cannot be static unless everything
is static and `createXxxState` are more verbose and accept additional
parameters: originalStateFactory, ttlConfig, timeProvider.
> Wrap state binder with TTL logic
> --------------------------------
>
> Key: FLINK-9513
> URL: https://issues.apache.org/jira/browse/FLINK-9513
> Project: Flink
> Issue Type: Sub-task
> Components: State Backends, Checkpointing
> Affects Versions: 1.6.0
> Reporter: Andrey Zagrebin
> Assignee: Andrey Zagrebin
> Priority: Major
> Labels: pull-request-available
> Fix For: 1.6.0
>
>
> The main idea is to wrap user state value with a class holding the value and
> the expiration timestamp (maybe meta data in future) and use the new object
> as a value in the existing implementations:
> {code:java}
> class TtlValue<V> {
> V value;
> long expirationTimestamp;
> }
> {code}
> The original state binder factory is wrapped with TtlStateBinder if TTL is
> enabled:
> {code:java}
> state = ttlConfig.updateType == DISABLED ?
> bind(binder) : bind(new TtlStateBinder(binder, timerService));
> {code}
> TtlStateBinder decorates the states produced by the original binder with TTL
> logic wrappers and adds TtlValue serialisation logic:
> {code:java}
> TtlStateBinder {
> StateBinder binder;
> ProcessingTimeProvier timeProvider; // System.currentTimeMillis()
> <V> TtlValueState<V> createValueState(valueDesc) {
> serializer = new TtlValueSerializer(valueDesc.getSerializer);
> ttlValueDesc = new ValueDesc(serializer, ...);
> // or implement custom TypeInfo
> originalStateWithTtl = binder.createValueState(valueDesc);
> return new TtlValueState(originalStateWithTtl, timeProvider);
> }
> // List, Map, ...
> }
> {code}
> TTL serializer should add expiration timestamp
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