amaliujia commented on a change in pull request #1725: URL: https://github.com/apache/ozone/pull/1725#discussion_r557147075
########## File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/ha/SCMDBTransactionBuffer.java ########## @@ -0,0 +1,101 @@ +/* + * 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 + * <p/> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p/> + * 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.hadoop.hdds.scm.ha; + +import org.apache.hadoop.hdds.scm.metadata.SCMMetadataStore; +import org.apache.hadoop.hdds.utils.db.BatchOperation; +import org.apache.hadoop.hdds.utils.db.Table; +import org.apache.ratis.statemachine.SnapshotInfo; + +import java.io.IOException; + +import static org.apache.hadoop.ozone.OzoneConsts.TRANSACTION_INFO_KEY; + +/** + * This is a transaction buffer that buffers SCM DB operations for Pipeline and + * Container. When flush this buffer to DB, a transaction info will also be + * written into DB to indicate the term and transaction index for the latest + * operation in DB. + */ +public class SCMDBTransactionBuffer { + private final SCMMetadataStore metadataStore; + private BatchOperation currentBatchOperation; + private SCMTransactionInfo latestTrxInfo; + private SnapshotInfo latestSnapshot; + + public SCMDBTransactionBuffer(SCMMetadataStore store) throws IOException { + this.metadataStore = store; + + // initialize a batch operation during construction time + currentBatchOperation = this.metadataStore.getStore().initBatchOperation(); + latestTrxInfo = store.getTransactionInfoTable().get(TRANSACTION_INFO_KEY); + if (latestTrxInfo == null) { + // transaction table is empty + latestTrxInfo = + SCMTransactionInfo + .builder() + .setTransactionIndex(-1) + .setCurrentTerm(0) + .build(); + } + latestSnapshot = latestTrxInfo.toSnapshotInfo(); + } + + public BatchOperation getCurrentBatchOperation() { + return currentBatchOperation; + } + + public void updateLatestTrxInfo(SCMTransactionInfo info) { + if (info.compareTo(this.latestTrxInfo) <= 0) { + throw new IllegalArgumentException( + "Updating DB buffer transaction info by an older transaction info, " + + "current: " + this.latestTrxInfo + ", updating to: " + info); + } + this.latestTrxInfo = info; + } + + public SCMTransactionInfo getLatestTrxInfo() { + return this.latestTrxInfo; + } + + public SnapshotInfo getLatestSnapshot() { + return latestSnapshot; + } + + public void setLatestSnapshot(SnapshotInfo latestSnapshot) { + this.latestSnapshot = latestSnapshot; + } + + public void flush() throws IOException { + // write latest trx info into trx table in the same batch + Table<String, SCMTransactionInfo> transactionInfoTable + = metadataStore.getTransactionInfoTable(); + transactionInfoTable.putWithBatch(currentBatchOperation, + TRANSACTION_INFO_KEY, latestTrxInfo); + + metadataStore.getStore().commitBatchOperation(currentBatchOperation); + currentBatchOperation.close(); + Review comment: The snapshot info is set also during the initialization. So not only `flush()` will need to update that information. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
