sanpwc commented on code in PR #4137: URL: https://github.com/apache/ignite-3/pull/4137#discussion_r1713304262
########## modules/transactions/src/main/java/org/apache/ignite/internal/tx/ActiveTxMinimumBeginTimeProvider.java: ########## @@ -0,0 +1,30 @@ +/* + * 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.tx; + +import org.apache.ignite.internal.hlc.HybridTimestamp; +import org.jetbrains.annotations.Nullable; + +/** + * Provides the minimum begin time among all active RW transactions started locally. + */ +@SuppressWarnings("InterfaceMayBeAnnotatedFunctional") +public interface ActiveTxMinimumBeginTimeProvider { + /** Returns the minimum begin time among all active RW transactions started locally. */ + @Nullable HybridTimestamp minimumBeginTime(); Review Comment: > // it is safe to return the current time as minimum tx begin time. > HybridTimestamp beforeDetermineTxTime = clockService.now(); I'm not sure that it's safe. I mean that there should be some gap between starting the transaction (and thus assigning some timestamp as tx.startTime) and registering it in `org.apache.ignite.internal.tx.impl.TxManagerImpl#localRwTxCounter`. The atomicity is achieved by using `inUpdateRwTxCountLock` ``` return localRwTxCounter.inUpdateRwTxCountLock(() -> { HybridTimestamp beginTs = clockService.now(); localRwTxCounter.incrementRwTxCount(beginTs); return beginTs; }); ``` And because you don't use the lock in computeLocalMinTxBeginTime the race is possible. -- 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]
