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ASF GitHub Bot commented on FLINK-9487: --------------------------------------- Github user sihuazhou commented on a diff in the pull request: https://github.com/apache/flink/pull/6159#discussion_r195299958 --- Diff: flink-runtime/src/main/java/org/apache/flink/runtime/state/AbstractKeyGroupPartitioner.java --- @@ -0,0 +1,227 @@ +/* + * 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; + +import org.apache.flink.util.Preconditions; + +import javax.annotation.Nonnegative; +import javax.annotation.Nonnull; + +/** + * Abstract class that contains the base algorithm for partitioning data into key-groups. This algorithm currently works + * with two array (input, output) for optimal algorithmic complexity. Notice that this could also be implemented over a + * single array, using some cuckoo-hashing-style element replacement. This would have worse algorithmic complexity but + * better space efficiency. We currently prefer the trade-off in favor of better algorithmic complexity. + */ --- End diff -- Maybe we could add a param annotation for `T`. > Prepare InternalTimerHeap for asynchronous snapshots > ---------------------------------------------------- > > Key: FLINK-9487 > URL: https://issues.apache.org/jira/browse/FLINK-9487 > Project: Flink > Issue Type: Sub-task > Components: State Backends, Checkpointing, Streaming > Reporter: Stefan Richter > Assignee: Stefan Richter > Priority: Major > Fix For: 1.6.0 > > > When we want to snapshot timers with the keyed backend state, this must > happen as part of an asynchronous snapshot. > The data structure {{InternalTimerHeap}} needs to offer support for this > through a lightweight copy mechanism (e.g. arraycopy of the timer queue, > because timers are immutable w.r.t. serialization). > We can also stop keeping the dedup maps in {{InternalTimerHeap}} separated by > key-group, all timers can go into one map. > Instead, we can implement online-partitioning as part of the asynchronous > operation, similar to what we do in {{CopyOnWriteStateTable}} snapshots. > Notice that in this intermediate state, the code will still run in the > synchronous part until we are integrated with the backends for async > snapshotting (next subtask of this jira). -- This message was sent by Atlassian JIRA (v7.6.3#76005)