nizhikov commented on code in PR #11044: URL: https://github.com/apache/ignite/pull/11044#discussion_r1400051383
########## modules/core/src/main/java/org/apache/ignite/internal/cdc/CdcManager.java: ########## @@ -0,0 +1,73 @@ +/* + * 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.cdc; + +import java.nio.ByteBuffer; +import java.util.Iterator; +import org.apache.ignite.cdc.CdcConsumer; +import org.apache.ignite.internal.pagemem.wal.record.CdcManagerRecord; +import org.apache.ignite.internal.pagemem.wal.record.CdcManagerStopRecord; +import org.apache.ignite.internal.processors.cache.GridCacheSharedManager; +import org.apache.ignite.internal.processors.cache.persistence.wal.WALPointer; +import org.jetbrains.annotations.Nullable; + +/** + * CDC manager responsible for logic of capturing data within Ignite node. There is a contract between {@link CdcManager} + * and {@link CdcMain}. Communication between these components are built with over WAL records. {@link CdcManager} can + * write some records, while {@link CdcMain} must listen to them. + * <ul> + * <li> + * This manager can write {@link CdcManagerRecord} that contains info about consumer state. + * This record must be handled by {@link CdcMain} the same way it handles {@link CdcConsumer#onEvents(Iterator)} + * when it returns {@code true}. + * </li> + * <li> + * This manager writes {@link CdcManagerStopRecord} after it stopped handling records by any reason. + * {@link CdcMain} should start consume records instead since last consumed {@link CdcManagerRecord}. + * </li> + * <li> + * The current behavior of {@link CdcManager} is persisted within {@link CdcConsumerState#saveCdcMode(CdcMode)}. + * After the mode set to {@link CdcMode#CDC_UTILITY_ACTIVE} it will not reset. + * </li> + * </ul> + * + * @see CdcConsumer#onEvents(Iterator) + * @see CdcConsumerState#saveCdcMode(CdcMode) + */ +public interface CdcManager extends GridCacheSharedManager { + /** + * Collects byte buffer contains WAL records. + * + * @param dataBuf Buffer that contains data to collect. + * @param off Offset of the data within the buffer. + * @param limit Limit of the data within the buffer. + */ + public void collect(ByteBuffer dataBuf, int off, int limit); Review Comment: Please, describe what a contract to interact with the buffer. Can we change buffer content? Can we store buffer or its part itself? What are the expectation of `collect` method implementation? Should it works as fast as possible? Can it blocks or invoke some slow operations? Is it on the hot path of the node lifecycle? How frequently it will be invoked? -- 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]
