jberragan commented on code in PR #99: URL: https://github.com/apache/cassandra-analytics/pull/99#discussion_r2001356175
########## cassandra-analytics-cdc-sidecar/src/main/java/org/apache/cassandra/cdc/sidecar/SidecarStatePersister.java: ########## @@ -0,0 +1,434 @@ +/* + * 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.cassandra.cdc.sidecar; + +import java.nio.ByteBuffer; +import java.util.ArrayList; +import java.util.List; +import java.util.Objects; +import java.util.concurrent.ConcurrentHashMap; +import java.util.concurrent.ConcurrentLinkedQueue; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.Future; +import java.util.stream.Collectors; +import java.util.stream.Stream; + +import com.google.common.annotations.VisibleForTesting; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.datastax.driver.core.ResultSetFuture; +import com.datastax.driver.core.ThreadLocalMonotonicTimestampGenerator; +import org.apache.cassandra.bridge.CdcBridgeFactory; +import org.apache.cassandra.bridge.TokenRange; +import org.apache.cassandra.cdc.CdcKryoRegister; +import org.apache.cassandra.cdc.api.CdcOptions; +import org.apache.cassandra.cdc.api.StatePersister; +import org.apache.cassandra.cdc.state.CdcState; +import org.apache.cassandra.spark.utils.AsyncExecutor; +import org.apache.cassandra.spark.utils.ThrowableUtils; +import org.apache.cassandra.util.CompressionUtil; +import org.jetbrains.annotations.NotNull; +import org.jetbrains.annotations.Nullable; + +/** + * SidecarStatePersister buffers CDC state and flushes at regular time intervals, so we only write the latest CDC state and don't wastefully write expired data. + */ +public class SidecarStatePersister implements StatePersister +{ + private static final Logger LOGGER = LoggerFactory.getLogger(SidecarStatePersister.class); + + // group latest state by jobId/token range, so we persist independently + protected final ConcurrentHashMap<PersistWrapper.Key, PersistWrapper> latestState = new ConcurrentHashMap<>(); + protected final ConcurrentLinkedQueue<TimedFutureWrapper> activeFlush = new ConcurrentLinkedQueue<>(); + private final ThreadLocalMonotonicTimestampGenerator timestampGenerator = new ThreadLocalMonotonicTimestampGenerator(); + private final SidecarCdcOptions sidecarCdcOptions; + private final CdcOptions cdcOptions; + private final SidecarCdcCassandraClient cassandraClient; + private final SidecarCdcStats sidecarCdcStats; + private final AsyncExecutor asyncExecutor; + volatile long timerId = -1L; + + public SidecarStatePersister(SidecarCdcOptions sidecarCdcOptions, + CdcOptions cdcOptions, + SidecarCdcStats sidecarCdcStats, + SidecarCdcCassandraClient cassandraClient, + AsyncExecutor asyncExecutor) + { + this.sidecarCdcOptions = sidecarCdcOptions; + this.cdcOptions = cdcOptions; + this.sidecarCdcStats = sidecarCdcStats; + this.cassandraClient = cassandraClient; + this.asyncExecutor = asyncExecutor; + } + + // StatePersister implemented methods + + @Override + public void persist(String jobId, int partitionId, @Nullable TokenRange tokenRange, @NotNull ByteBuffer buf) + { + final PersistWrapper latest = new PersistWrapper(jobId, partitionId, tokenRange, buf, timestampGenerator.next()); + PersistWrapper.Key key = latest.key(); + if (!latest.equals(this.latestState.get(key))) + { + this.latestState.compute(key, (k, prev) -> !latest.equals(prev) ? latest : prev); + } + } + + @NotNull + @Override + public List<CdcState> loadState(String jobId, int partitionId, @Nullable TokenRange tokenRange) + { + CompressionUtil compressionUtil = CdcBridgeFactory.get(cdcOptions.version()).compressionUtil(); + List<Integer> sizes = new ArrayList<>(); + // deserialize and merge the CDC state objects into canonical view + List<CdcState> result = loadStateForRange(jobId, tokenRange) + .peek(bytes -> sizes.add(bytes.length)) + .map(bytes -> CdcState.deserialize(CdcKryoRegister.kryo(), compressionUtil, bytes)) Review Comment: I mean...how does that improve it? -- This is an automated message from the Apache Git Service. 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