/* * 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. */ /** * Hints subsystem consists of several components. * * {@link org.apache.cassandra.hints.Hint} encodes all the required metadata and the mutation being hinted. * * {@link org.apache.cassandra.hints.HintsBuffer} provides a temporary buffer for writing the hints to in a concurrent manner, * before we flush them to disk. * * {@link org.apache.cassandra.hints.HintsBufferPool} is responsible for submitting {@link org.apache.cassandra.hints.HintsBuffer} * instances for flushing when they exceed their capacity, and for maitaining a reserve {@link org.apache.cassandra.hints.HintsBuffer} * instance, and creating extra ones if flushing cannot keep up with arrival rate. * * {@link org.apache.cassandra.hints.HintsWriteExecutor} is a single-threaded executor that performs all the writing to disk. * * {@link org.apache.cassandra.hints.HintsDispatchExecutor} is a multi-threaded executor responsible for dispatch of * the hints to their destinations. * * {@link org.apache.cassandra.hints.HintsStore} tracks the state of all hints files (written and being written to) * for a given host id destination. * * {@link org.apache.cassandra.hints.HintsCatalog} maintains the mapping of host ids to {@link org.apache.cassandra.hints.HintsStore} * instances, and provides some aggregate APIs. * * {@link org.apache.cassandra.hints.HintsService} wraps the catalog, the pool, and the two executors, acting as a front-end * for hints. */ package org.apache.cassandra.hints;