smjn commented on code in PR #22601: URL: https://github.com/apache/kafka/pull/22601#discussion_r3451097140
########## server/src/main/java/org/apache/kafka/server/share/dlq/ShareGroupDLQRecordFetcher.java: ########## @@ -0,0 +1,281 @@ +/* + * 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.kafka.server.share.dlq; + +import org.apache.kafka.common.TopicIdPartition; +import org.apache.kafka.common.protocol.Errors; +import org.apache.kafka.common.record.internal.MemoryRecords; +import org.apache.kafka.common.record.internal.Record; +import org.apache.kafka.common.record.internal.RecordBatch; +import org.apache.kafka.common.record.internal.Records; +import org.apache.kafka.common.requests.FetchRequest; +import org.apache.kafka.common.utils.Time; +import org.apache.kafka.server.share.LogReader; +import org.apache.kafka.server.storage.log.FetchIsolation; +import org.apache.kafka.server.storage.log.FetchParams; +import org.apache.kafka.storage.internals.log.FetchDataInfo; +import org.apache.kafka.storage.internals.log.LogReadResult; +import org.apache.kafka.storage.internals.log.RemoteStorageFetchInfo; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.HashMap; +import java.util.LinkedHashMap; +import java.util.Map; +import java.util.Optional; +import java.util.OptionalLong; +import java.util.Set; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.CompletionException; + +/** + * Reads the original source records for the offset range described by a {@link ShareGroupDLQRecordParameter} + * so they can be copied into a DLQ record. Local reads are performed inline in a loop; when an offset has + * been tiered off the local log the records are fetched asynchronously from the remote tier and the loop + * resumes once the read completes (so the caller's thread is never blocked on remote storage IO). + * + * <p>Best-effort: the returned future always completes normally with whatever records could be read. + * Offsets that cannot be read - locally or remotely - are simply absent from the map, leaving the caller + * to produce a DLQ record with headers only for them. + * + * <p>Instances are single-use: create one fetcher per {@link #fetch()} call. + */ +public class ShareGroupDLQRecordFetcher { Review Comment: @apoorvmittal10 That would widen the scope quite a bit, unless we want the to make changes to `DelayedShareFetch` as it is on the hot path for `read`. The code is sync in that class which will need to be converted to `async`. It is not a question of: > if should go for local or remote fetch - Remote read, by design requires the local fetch to complete so local AND remote precludes the possibility of the caller only fetching remote data and not local. Hence, this will be a wider refactor and IMO not in scope for current PR. -- 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]
