[GitHub] [flink] GJL commented on a change in pull request #10999: [FLINK-15143] Docs for FLIP-49 TM memory model and configuration guide

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GJL commented on a change in pull request #10999: [FLINK-15143] Docs for FLIP-49 TM memory model and configuration guide
URL: https://github.com/apache/flink/pull/10999#discussion_r375974361
 
 

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 File path: docs/ops/memory/mem_tuning.md
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+---
+title: "Memory tuning guide"
+nav-parent_id: ops_mem
+nav-pos: 3
+---
+<!--
+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.
+-->
+
+In addition to the [main memory setup guide](mem_setup.html), this section explains how to setup memory of task executors
+depending on the use case and which options are important in which case.
+
+* toc
+{:toc}
+
+## Configure memory for standalone deployment
+
+It is recommended to configure [total Flink memory](mem_setup.html#configure-total-memory)
+([`taskmanager.memory.flink.size`](../config.html#taskmanager-memory-flink-size)) or its [components](mem_setup.html#detailed-memory-model)
+for [standalone deployment](../deployment/cluster_setup.html) where you want to declare how much memory is given to Flink itself.
+Additionally, you can adjust *JVM metaspace* if it causes [problems](mem_trouble.html#outofmemoryerror-metaspace).
+
+The *total Process memory* is not relevant because *JVM overhead* is not controlled by Flink or deployment environment,
+only physical resources of the executing machine matter in this case.
+
+## Configure memory for containers
+
+It is recommended to configure [total process memory](mem_setup.html#configure-total-memory)
+([`taskmanager.memory.process.size`](../config.html#taskmanager-memory-process-size)) for the containerized deployments
+([Kubernetes](../deployment/kubernetes.html), [Yarn](../deployment/yarn_setup.html) or [Mesos](../deployment/mesos.html)).
+It declares how much memory in total should be assigned to the Flink *JVM process* and corresponds to the size of the requested container.
+
+<span class="label label-info">Note</span> If you configure the *total Flink memory* Flink will implicitly add JVM memory components
+to derive the *total process memory* and request a container with the memory of that derived size,
+see also [detailed Memory Model](mem_setup.html#detailed-memory-model).
+
+<div class="alert alert-warning">
+  <strong>Warning:</strong> If Flink or user code allocates unmanaged off-heap (native) memory beyond the container size
+  the job can fail because the deployment environment can kill the offending containers.
+</div>
+See also description of [container memory exceeded](mem_trouble.html#container-memory-exceeded) failure.
+
+## Configure memory for state backends
+
+When deploying a Flink streaming application, the type of [state backend](../state/state_backends.html) used
+will dictate the optimal memory configurations of your cluster.
+
+### Heap state backend
+
+When running a stateless job or using a heap state backend ([MemoryStateBackend](../state/state_backends.html#the-memorystatebackend)
+or [FsStateBackend](../state/state_backends.html#the-fsstatebackend), set [managed memory](mem_setup.html#managed-memory) to zero.
+This will ensure that the maximum amount of memory is allocated for user code on the JVM.
+
+### RocksDB state backend
+
+The [RocksDBStateBackend](../state/state_backends.html#the-rocksdbstatebackend) uses native memory. By default,
+RocksDB is setup to limit native memory allocation to the size of the [managed memory](mem_setup.html#managed-memory).
+Therefore, it is important to reserve enough *managed memory* for your state use case. If you disable the default RocksDB memory control,
+task executors can be killed in containerized deployments if RocksDB allocates memory above the limit of the requested container size
+(the [total process memory](mem_setup.html#configure-total-memory)).
+See also [state.backend.rocksdb.memory.managed](../config.html#state-backend-rocksdb-memory-managed).
+
+## Configure memory for batch jobs
+
+Flink's batch operators leverage [managed memory](../memory/mem_setup.html#managed-memory) to run more efficiently.
+In doing so, some operations can be performed directly on raw data without having to be deserialized into Java objects.
+This means that [managed memory](../memory/mem_setup.html#managed-memory) configurations have practical effects
+on the performance of your applications. Flink will attempt to allocate and use as much [managed memory](../memory/mem_setup.html#managed-memory)
+as configured for batch jobs but not go beyond its limits. This prevents `OutOfMemoryError`'s because Flink knows precisely
 
 Review comment:
   Plural is without `'` just `s`

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