[
https://issues.apache.org/jira/browse/FLINK-4856?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15875844#comment-15875844
]
ASF GitHub Bot commented on FLINK-4856:
---------------------------------------
Github user StefanRRichter commented on a diff in the pull request:
https://github.com/apache/flink/pull/3336#discussion_r102188520
--- Diff:
flink-contrib/flink-statebackend-rocksdb/src/main/java/org/apache/flink/contrib/streaming/state/RocksDBMapState.java
---
@@ -0,0 +1,579 @@
+/*
+ * 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
+ * <p/>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p/>
+ * 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.contrib.streaming.state;
+
+import org.apache.flink.api.common.state.MapState;
+import org.apache.flink.api.common.state.MapStateDescriptor;
+import org.apache.flink.api.common.typeutils.TypeSerializer;
+import org.apache.flink.api.java.tuple.Tuple2;
+import org.apache.flink.api.java.tuple.Tuple3;
+import org.apache.flink.api.java.tuple.Tuple4;
+import org.apache.flink.core.memory.ByteArrayInputStreamWithPos;
+import org.apache.flink.core.memory.ByteArrayOutputStreamWithPos;
+import org.apache.flink.core.memory.DataInputViewStreamWrapper;
+import org.apache.flink.core.memory.DataOutputViewStreamWrapper;
+import
org.apache.flink.runtime.query.netty.message.KvStateRequestSerializer;
+import org.apache.flink.runtime.state.KeyGroupRangeAssignment;
+import org.apache.flink.runtime.state.internal.InternalMapState;
+import org.apache.flink.util.Preconditions;
+import org.rocksdb.ColumnFamilyHandle;
+import org.rocksdb.RocksDB;
+import org.rocksdb.RocksDBException;
+import org.rocksdb.RocksIterator;
+import org.rocksdb.WriteOptions;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.Map;
+
+/**
+ * {@link MapState} implementation that stores state in RocksDB.
+ * <p>
+ * <p>{@link RocksDBStateBackend} must ensure that we set the
+ * {@link org.rocksdb.StringAppendOperator} on the column family that we
use for our state since
+ * we use the {@code merge()} call.
+ *
+ * @param <K> The type of the key.
+ * @param <N> The type of the namespace.
+ * @param <UK> The type of the keys in the map state.
+ * @param <UV> The type of the values in the map state.
+ */
+public class RocksDBMapState<K, N, UK, UV>
+ extends AbstractRocksDBState<K, N, MapState<UK, UV>,
MapStateDescriptor<UK, UV>, Map<UK, UV>>
+ implements InternalMapState<N, UK, UV> {
+
+ /** Serializer for the keys and values */
+ private final TypeSerializer<UK> userKeySerializer;
+ private final TypeSerializer<UV> userValueSerializer;
+
+ /**
+ * We disable writes to the write-ahead-log here. We can't have these
in the base class
+ * because JNI segfaults for some reason if they are.
+ */
+ private final WriteOptions writeOptions;
--- End diff --
In any case, the problem still persists that the native resource
`WriteOptions` is never closed properly. It might be ok, because right now the
task will typically end when is should be released, but it is still not
completely clean and can produce leaks. I would be ok with merging this and
creating another JIRA for this. What do you think @aljoscha ?
> Add MapState for keyed streams
> ------------------------------
>
> Key: FLINK-4856
> URL: https://issues.apache.org/jira/browse/FLINK-4856
> Project: Flink
> Issue Type: New Feature
> Components: DataStream API, State Backends, Checkpointing
> Reporter: Xiaogang Shi
> Assignee: Xiaogang Shi
>
> Many states in keyed streams are organized as key-value pairs. Currently,
> these states are implemented by storing the entire map into a ValueState or a
> ListState. The implementation however is very costly because all entries have
> to be serialized/deserialized when updating a single entry. To improve the
> efficiency of these states, MapStates are urgently needed.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
