belliottsmith commented on code in PR #26: URL: https://github.com/apache/cassandra-accord/pull/26#discussion_r1093737046
########## accord-core/src/main/java/accord/coordinate/CoordinateSyncPoint.java: ########## @@ -0,0 +1,93 @@ +/* + * 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 accord.coordinate; + +import accord.local.Node; +import accord.messages.Apply; +import accord.messages.PreAccept.PreAcceptOk; +import accord.primitives.*; +import accord.primitives.Txn.Kind; +import org.apache.cassandra.utils.concurrent.Future; + +import java.util.List; + +import static accord.coordinate.Propose.Invalidate.proposeAndCommitInvalidate; +import static accord.primitives.Timestamp.mergeMax; +import static accord.primitives.Txn.Kind.ExclusiveSyncPoint; +import static accord.utils.Functions.foldl; + +/** + * Perform initial rounds of PreAccept and Accept until we have reached agreement about when we should execute. + * If we are preempted by a recovery coordinator, we abort and let them complete (and notify us about the execution result) + * + * TODO (desired, testing): dedicated burn test to validate outcomes + */ +public class CoordinateSyncPoint extends CoordinatePreAccept<SyncPoint> +{ + private CoordinateSyncPoint(Node node, TxnId txnId, Txn txn, FullRoute<?> route) + { + super(node, txnId, txn, route); + } + + public static Future<SyncPoint> exclusive(Node node, Seekables<?, ?> keysOrRanges) + { + return coordinate(ExclusiveSyncPoint, node, keysOrRanges); + } + + public static Future<SyncPoint> inclusive(Node node, Seekables<?, ?> keysOrRanges) + { + return coordinate(Kind.SyncPoint, node, keysOrRanges); + } + + private static Future<SyncPoint> coordinate(Kind kind, Node node, Seekables<?, ?> keysOrRanges) + { + TxnId txnId = node.nextTxnId(kind, keysOrRanges.domain()); + FullRoute<?> route = node.computeRoute(txnId, keysOrRanges); + CoordinateSyncPoint coordinate = new CoordinateSyncPoint(node, txnId, node.agent().emptyTxn(kind, keysOrRanges), route); + coordinate.start(); + return coordinate; + } + + void onPreAccepted(List<PreAcceptOk> successes) + { + Deps deps = Deps.merge(successes, ok -> ok.deps); + Timestamp executeAt = foldl(successes, (ok, prev) -> mergeMax(ok.witnessedAt, prev), Timestamp.NONE); + if (executeAt.isRejected()) + { + proposeAndCommitInvalidate(node, Ballot.ZERO, txnId, route.homeKey(), route, executeAt, this); + } + else + { + // SyncPoint transactions always propose their own txnId as their executeAt, as they are not really executed. + // They only create happens-after relationships wrt their dependencies, which represent all transactions + // that *may* execute before their txnId, so once these dependencies apply we can say that any action that + // awaits these dependencies applies after them. In the case of ExclusiveSyncPoint, we additionally guarantee + // that no lower TxnId can later apply. + new Propose<SyncPoint>(node, tracker.topologies(), Ballot.ZERO, txnId, txn, route, deps, txnId, this) Review Comment: Happy to introduce an inner class. I did previously have a static method I could pass a callback to that would create an anonymous class to wrap the callback but that felt wrong. -- 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]
