io.atomix.copycat.server.storage.compaction.package-info Maven / Gradle / Ivy
/*
* Copyright 2015 the original author or authors.
*
* Licensed 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
*/
/**
* Classes and interfaces that support efficient Raft {@link io.atomix.copycat.server.storage.Log log} compaction.
*
* The log compaction package implements compaction for Copycat {@link io.atomix.copycat.server.storage.Log logs} using
* a custom log cleaning algorithm. As entries are written to the log and applied to the server's state machine, the
* state machine can arbitrarily mark entries for removal from the log. Periodically, a set of log compaction threads
* will compact {@link io.atomix.copycat.server.storage.Segment segment}s of the log in the background. Log compaction
* is performed in two phases: {@link io.atomix.copycat.server.storage.compaction.MinorCompactionTask minor} and
* {@link io.atomix.copycat.server.storage.compaction.MajorCompactionTask major}. The minor compaction process efficiently
* rewrites individual segments to remove standard entries that have been marked for cleaning. The major compaction process
* periodically rewrites the entire log to combine segments that have previously been compacted.
*
* @author Jordan Halterman
*/
package io.atomix.copycat.server.storage.compaction;