frankgh commented on code in PR #4708: URL: https://github.com/apache/cassandra/pull/4708#discussion_r3562236508
########## src/java/org/apache/cassandra/locator/WriteResponseTracker.java: ########## @@ -0,0 +1,237 @@ +/* + * 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.cassandra.locator; + +import java.util.function.Predicate; + +import org.apache.cassandra.exceptions.RequestFailureReason; + +/** + * Response tracker for writes with pending replicas using the double count model. + * <p> + * Two requirements must be satisfied for success: + * <ol> + * <li>Committed replicas must satisfy base CL: {@code committedSuccesses >= baseBlockFor}</li> + * <li>Total replicas (committed + pending) must satisfy: {@code totalSuccesses >= totalBlockFor}</li> + * </ol> + * <p> + * This ensures both consistency (committed replicas have the data) and bootstrap safety + * (pending replicas also receive the write). + * <p> + * Implemented by composing two {@link SimpleResponseTracker}s: + * <ul> + * <li>committedTracker: tracks responses from committed replicas only</li> + * <li>totalTracker: tracks responses from all replicas (committed + pending)</li> + * </ul> + * <p> + * Thread-safe through delegation to thread-safe SimpleResponseTrackers. + */ +public class WriteResponseTracker implements ResponseTracker +{ + private final SimpleResponseTracker natural; + private final SimpleResponseTracker total; + + /** + * Create a write response tracker with the double count model. + * + * @param baseBlockFor number of committed replica responses required for CL + * @param totalBlockFor total responses required (baseBlockFor + pending count) + * @param committedReplicas number of committed replicas available + * @param pendingReplicas number of pending replicas available + * @param isPending predicate to determine if an endpoint is pending + */ + public WriteResponseTracker(int baseBlockFor, + int totalBlockFor, + int committedReplicas, + int pendingReplicas, + Predicate<InetAddressAndPort> isPending) + { + this(baseBlockFor, totalBlockFor, committedReplicas, pendingReplicas, isPending, null); + } + + /** + * Create a write response tracker with the double count model and a filter. + * + * @param naturalBlockFor number of committed replica responses required for CL + * @param totalBlockFor total responses required (naturalBlockFor + pending count) + * @param naturalReplicas number of committed replicas available + * @param pendingReplicas number of pending replicas available + * @param isPending predicate to determine if an endpoint is pending + * @param filter predicate to filter which responses count (e.g., InOurDc for LOCAL_QUORUM) + */ + public WriteResponseTracker(int naturalBlockFor, + int totalBlockFor, + int naturalReplicas, + int pendingReplicas, + Predicate<InetAddressAndPort> isPending, + Predicate<InetAddressAndPort> filter) + { + if (naturalBlockFor < 0) + throw new IllegalArgumentException("naturalBlockFor must be non-negative: " + naturalBlockFor); + if (totalBlockFor < naturalBlockFor) + throw new IllegalArgumentException("totalBlockFor (" + totalBlockFor + ") must be >= naturalBlockFor (" + naturalBlockFor + ")"); + if (naturalReplicas < 0) + throw new IllegalArgumentException("naturalReplicas must be non-negative: " + naturalReplicas); + if (pendingReplicas < 0) + throw new IllegalArgumentException("pendingReplicas must be non-negative: " + pendingReplicas); + if (naturalBlockFor > naturalReplicas) + throw new IllegalArgumentException("naturalBlockFor (" + naturalBlockFor + ") cannot exceed naturalReplicas (" + naturalReplicas + ")"); + if (totalBlockFor > naturalReplicas + pendingReplicas) + throw new IllegalArgumentException("totalBlockFor (" + totalBlockFor + ") cannot exceed total replicas (" + (naturalReplicas + pendingReplicas) + ")"); + if (isPending == null) + throw new IllegalArgumentException("isPending predicate cannot be null"); + + Predicate<InetAddressAndPort> naturalFilter = isPending.negate(); + if (filter != null) + naturalFilter = naturalFilter.and(filter); + + this.natural = new SimpleResponseTracker(naturalBlockFor, naturalReplicas, naturalFilter); + this.total = new SimpleResponseTracker(totalBlockFor, naturalReplicas + pendingReplicas, filter); + } + + private WriteResponseTracker(SimpleResponseTracker natural, SimpleResponseTracker total) + { + this.natural = natural; + this.total = total; + } + + @Override + public void onResponse(InetAddressAndPort from) + { + natural.onResponse(from); + total.onResponse(from); + } + + @Override + public void onFailure(InetAddressAndPort from, RequestFailureReason reason) + { + natural.onFailure(from, reason); + total.onFailure(from, reason); + } + + @Override + public boolean isComplete() + { + // Early failure if either tracker fails + if (natural.isComplete() && !natural.isSuccessful()) + return true; + if (total.isComplete() && !total.isSuccessful()) + return true; + + // Success requires both to succeed + return natural.isSuccessful() && total.isSuccessful(); + } + + @Override + public boolean isSuccessful() + { + return natural.isSuccessful() && total.isSuccessful(); + } + + @Override + public int required() + { + // Return total requirement for error messages + return total.required(); + } + + @Override + public int received() + { + // Return total successes for error messages + return total.received(); + } + + @Override + public int failures() + { + // Return total failures for error messages + return total.failures(); + } + + @Override + public boolean countsTowardQuorum(InetAddressAndPort from) + { + return total.countsTowardQuorum(from); + } + + public int committedReceived() + { + return natural.received(); + } + + public int pendingReceived() Review Comment: ah yes! I see the comment there . -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
