nizhikov commented on code in PR #10314: URL: https://github.com/apache/ignite/pull/10314#discussion_r1030212268
########## modules/core/src/main/java/org/apache/ignite/internal/processors/cache/consistentcut/ConsistentCutManager.java: ########## @@ -0,0 +1,224 @@ +/* + * 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.ignite.internal.processors.cache.consistentcut; + +import java.util.Objects; +import java.util.UUID; +import java.util.concurrent.atomic.AtomicReference; +import org.apache.ignite.IgniteCheckedException; +import org.apache.ignite.internal.pagemem.wal.record.ConsistentCutFinishRecord; +import org.apache.ignite.internal.pagemem.wal.record.ConsistentCutStartRecord; +import org.apache.ignite.internal.processors.cache.GridCacheMessage; +import org.apache.ignite.internal.processors.cache.GridCacheSharedContext; +import org.apache.ignite.internal.processors.cache.GridCacheSharedManagerAdapter; +import org.apache.ignite.internal.processors.cache.distributed.dht.preloader.GridDhtPartitionsExchangeFuture; +import org.apache.ignite.internal.processors.cache.distributed.dht.preloader.PartitionsExchangeAware; +import org.apache.ignite.internal.processors.cache.transactions.IgniteInternalTx; +import org.apache.ignite.internal.processors.cache.transactions.IgniteTxAdapter; +import org.apache.ignite.internal.processors.cache.transactions.IgniteTxManager; +import org.apache.ignite.internal.util.typedef.internal.U; +import org.jetbrains.annotations.Nullable; + +import static org.apache.ignite.internal.processors.cache.GridCacheUtils.baselineNode; + +/** + * Processes all stuff related to Consistent Cut. + * <p> + * Consistent Cut is a distributed algorithm that defines two set of transactions - BEFORE and AFTER cut. It guarantees that every + * transaction committed BEFORE also will be committed BEFORE on every other node participated in the transaction. + * It means that an Ignite nodes can safely recover themselves to the consistent BEFORE state without any coordination with each other. + * <p> + * The algorithm starts on Ignite node by snapshot creation command. Other nodes are notified with discovery message of snapshot + * distributed process or by transaction messages {@link ConsistentCutAwareMessage}. + * <p> + * The algorithm consist of steps: + * 1. On receiving new Consistent Cut ID it immediately creates new {@link ConsistentCutFuture} before processing the message. + * 2. It starts wrapping all transaction messages to {@link ConsistentCutAwareMessage}. + * 3. Every transaction holds {@link IgniteTxAdapter#cutId()} AFTER which it committed. Value of this field is defined + * at node that commits first in distributed transaction. + * 4. On baseline nodes in {@link BaselineConsistentCutFuture}: + * - it writes {@link ConsistentCutStartRecord} to limit amount of transactions on the AFTER side of Consistent Cut. + * After writing this record it's safe to miss transactions on the AFTER side. + * - it collects active transactions to check which side of Consistent Cut they belong to. This collection contains all + * not-committed yet transactions that are on the BEFORE side. + * - it awaits every transaction in this collection to be committed to decide which side of Consistent Cut they belong to. + * - after the all active transactions finished it finishes Consistent Cut with writing {@link ConsistentCutFinishRecord} that contains + * collection of transactions on the BEFORE and AFTER sides. + * 5. After Consistent Cut finished globally, it clears {@link ConsistentCutFuture} variable and stops wrapping messages. + */ +public class ConsistentCutManager extends GridCacheSharedManagerAdapter implements PartitionsExchangeAware { + /** Current Consistent Cut, {@code null} if not running. */ + private final AtomicReference<ConsistentCutFuture> cutFutRef = new AtomicReference<>(); + + /** ID of the last finished {@link ConsistentCutFuture}. Required to avoid re-run {@link ConsistentCutFuture} with the same id. */ + protected volatile UUID lastFinishedCutId; + + /** {@inheritDoc} */ + @Override public void start0() throws IgniteCheckedException { + super.start0(); + + cctx.exchange().registerExchangeAwareComponent(this); + } + + /** {@inheritDoc} */ + @Override public void stop0(boolean cancel) { + cancelCut(new IgniteCheckedException("Ignite node is stopping.")); + } + + /** + * Stops Consistent Cut in case of baseline topology changed. + */ + @Override public void onInitBeforeTopologyLock(GridDhtPartitionsExchangeFuture fut) { + if (fut.changedBaseline() || fut.isBaselineNodeFailed()) + cancelCut(new IgniteCheckedException("Ignite topology changed, can't finish Consistent Cut.")); + } + + /** + * Registers transaction before it is removed from {@link IgniteTxManager#activeTransactions()}. + * + * @param tx Transaction. + */ + public void onRemoveActiveTransaction(IgniteInternalTx tx) { + if (clientNode()) + return; + + ConsistentCutFuture cut = cutFutRef.get(); + + if (cut != null) + ((BaselineConsistentCutFuture)cut).onRemoveActiveTransaction(tx.finishFuture()); + } + + /** + * Set transaction Consistent Cut ID. + * + * @param tx Transaction. + */ + public void setTransactionCutId(IgniteInternalTx tx) { + ConsistentCutFuture cut = cutFutRef.get(); + + if (cut != null) + tx.cutId(cut.id()); + } + + /** + * Wraps a transaction message if Consistent Cut is running. + * + * @param txMsg Transaction message to wrap. + * @param txCutId Consistent Cut ID after which transaction committed, if specified. + */ + public static GridCacheMessage wrapMessage( + GridCacheSharedContext<?, ?> cctx, + GridCacheMessage txMsg, + @Nullable UUID txCutId + ) { + if (cctx.consistentCutMgr() == null) + return txMsg; + + ConsistentCutFuture cut = cctx.consistentCutMgr().cutFuture(); + + if (cut != null) + return new ConsistentCutAwareMessage(txMsg, cut.id(), txCutId); + + return txMsg; + } + + /** + * Handles received Consistent Cut ID from remote node. It compares it with the latest ID that local node is aware of. + * Init local Consistent Cut procedure if received ID is a new one. + * + * @param id ID of {@link ConsistentCutFuture}. + */ + public void handleConsistentCutId(UUID id) { + ConsistentCutFuture cutFut = cutFutRef.get(); + + if (cutFut != null || Objects.equals(id, lastFinishedCutId)) + return; + + ConsistentCutFuture newCutFut = clientNode() ? new ClientConsistentCutFuture(id) : newBaselineConsistentCut(id); + + if (!cutFutRef.compareAndSet(cutFut, newCutFut)) + return; + + if (newCutFut.isDone()) + return; + + cctx.kernalContext().pools().getSnapshotExecutorService().submit(() -> { + BaselineConsistentCutFuture cut = (BaselineConsistentCutFuture)newCutFut; + + try { + cut.init(); + + if (log.isDebugEnabled()) + log.debug("Prepared Consistent Cut: " + id); + } + catch (IgniteCheckedException e) { + U.error(log, "Failed to handle Consistent Cut: " + id, e); + + cut.onDone(e); + } + }); + } + + /** Creates new Consistent Cut future for baseline nodes. */ + protected BaselineConsistentCutFuture newBaselineConsistentCut(UUID id) { + return new BaselineConsistentCutFuture(cctx, id); + } + + /** + * Cancels local Consistent Cut with error. + * + * @param err Error. + */ + public void cancelCut(Throwable err) { + ConsistentCutFuture cut = cutFutRef.get(); + + if (cut != null && !cut.isDone()) + ((BaselineConsistentCutFuture)cut).onDone(err); + + cleanLocalCut(); + } + + /** + * @return Current running Consistent Cut future, if cut isn't running then {@code null}. + */ + public @Nullable ConsistentCutFuture cutFuture() { + return cutFutRef.get(); + } + + /** + * Cleans local Consistent Cut, stop signing outgoing messages. + */ + public void cleanLocalCut() { + ConsistentCutFuture cut = cutFutRef.get(); + + if (log.isDebugEnabled()) + log.debug("Clean local cut: " + cut); + + if (cut == null) + return; + + lastFinishedCutId = cut.id(); + + cutFutRef.set(null); + } + + /** */ + private boolean clientNode() { Review Comment: can we revert the logic and name method `cutAwareNode` like: ``` public void onRemoveActiveTransaction(IgniteInternalTx tx) { if (!cutAwareNode()) return; ``` -- This is an automated message from the Apache Git Service. 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