-
Notifications
You must be signed in to change notification settings - Fork 25k
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Introducing a translog deletion policy (#24950)
Currently, the decisions regarding which translog generation files to delete are hard coded in the interaction between the `InternalEngine` and the `Translog` classes. This PR extracts it to a dedicated class called `TranslogDeletionPolicy`, for two main reasons: 1) Simplicity - the code is easier to read and understand (no more two phase commit on the translog, the Engine can just commit and the translog will respond) 2) Preparing for future plans to extend the logic we need - i.e., retain multiple lucene commit and also introduce a size based retention logic, allowing people to always keep a certain amount of translog files around. The latter is useful to increase the chance of an ops based recovery.
- Loading branch information
Showing
9 changed files
with
519 additions
and
297 deletions.
There are no files selected for viewing
86 changes: 86 additions & 0 deletions
86
core/src/main/java/org/elasticsearch/index/engine/CombinedDeletionPolicy.java
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,86 @@ | ||
| /* | ||
| * Licensed to Elasticsearch under one or more contributor | ||
| * license agreements. See the NOTICE file distributed with | ||
| * this work for additional information regarding copyright | ||
| * ownership. Elasticsearch 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.elasticsearch.index.engine; | ||
|
|
||
| import org.apache.lucene.index.IndexCommit; | ||
| import org.apache.lucene.index.IndexDeletionPolicy; | ||
| import org.apache.lucene.index.SnapshotDeletionPolicy; | ||
| import org.elasticsearch.index.translog.Translog; | ||
| import org.elasticsearch.index.translog.TranslogDeletionPolicy; | ||
|
|
||
| import java.io.IOException; | ||
| import java.util.List; | ||
|
|
||
| /** | ||
| * An {@link IndexDeletionPolicy} that coordinates between Lucene's commits and the retention of translog generation files, | ||
| * making sure that all translog files that are needed to recover from the Lucene commit are not deleted. | ||
| */ | ||
| class CombinedDeletionPolicy extends IndexDeletionPolicy { | ||
|
|
||
| private final TranslogDeletionPolicy translogDeletionPolicy; | ||
| private final EngineConfig.OpenMode openMode; | ||
|
|
||
| private final SnapshotDeletionPolicy indexDeletionPolicy; | ||
|
|
||
| CombinedDeletionPolicy(SnapshotDeletionPolicy indexDeletionPolicy, TranslogDeletionPolicy translogDeletionPolicy, | ||
| EngineConfig.OpenMode openMode) { | ||
| this.indexDeletionPolicy = indexDeletionPolicy; | ||
| this.translogDeletionPolicy = translogDeletionPolicy; | ||
| this.openMode = openMode; | ||
| } | ||
|
|
||
| @Override | ||
| public void onInit(List<? extends IndexCommit> commits) throws IOException { | ||
| indexDeletionPolicy.onInit(commits); | ||
| switch (openMode) { | ||
| case CREATE_INDEX_AND_TRANSLOG: | ||
| assert commits.isEmpty() : "index is being created but we already have commits"; | ||
| break; | ||
| case OPEN_INDEX_CREATE_TRANSLOG: | ||
| assert commits.isEmpty() == false : "index is opened, but we have no commits"; | ||
| break; | ||
| case OPEN_INDEX_AND_TRANSLOG: | ||
| assert commits.isEmpty() == false : "index is opened, but we have no commits"; | ||
| setLastCommittedTranslogGeneration(commits); | ||
| break; | ||
| default: | ||
| throw new IllegalArgumentException("unknown openMode [" + openMode + "]"); | ||
| } | ||
| } | ||
|
|
||
| @Override | ||
| public void onCommit(List<? extends IndexCommit> commits) throws IOException { | ||
| indexDeletionPolicy.onCommit(commits); | ||
| setLastCommittedTranslogGeneration(commits); | ||
| } | ||
|
|
||
| private void setLastCommittedTranslogGeneration(List<? extends IndexCommit> commits) throws IOException { | ||
| // when opening an existing lucene index, we currently always open the last commit. | ||
| // we therefore use the translog gen as the one that will be required for recovery | ||
| final IndexCommit indexCommit = commits.get(commits.size() - 1); | ||
| assert indexCommit.isDeleted() == false : "last commit is deleted"; | ||
| long minGen = Long.parseLong(indexCommit.getUserData().get(Translog.TRANSLOG_GENERATION_KEY)); | ||
| translogDeletionPolicy.setMinTranslogGenerationForRecovery(minGen); | ||
| } | ||
|
|
||
| public SnapshotDeletionPolicy getIndexDeletionPolicy() { | ||
| return indexDeletionPolicy; | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.