eldenmoon commented on code in PR #27764: URL: https://github.com/apache/doris/pull/27764#discussion_r1414931441
########## fe/fe-core/src/main/java/org/apache/doris/common/util/FetchRemoteTabletSchemaUtil.java: ########## @@ -0,0 +1,334 @@ +// 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.doris.common.util; + +import org.apache.doris.catalog.AggregateType; +import org.apache.doris.catalog.ArrayType; +import org.apache.doris.catalog.Column; +import org.apache.doris.catalog.Env; +import org.apache.doris.catalog.MapType; +import org.apache.doris.catalog.Replica; +import org.apache.doris.catalog.StructType; +import org.apache.doris.catalog.Tablet; +import org.apache.doris.catalog.Type; +import org.apache.doris.common.AnalysisException; +import org.apache.doris.proto.InternalService.PFetchRemoteSchemaRequest; +import org.apache.doris.proto.InternalService.PFetchRemoteSchemaResponse; +import org.apache.doris.proto.InternalService.PTabletsLocation; +import org.apache.doris.proto.OlapFile.ColumnPB; +import org.apache.doris.proto.OlapFile.TabletSchemaPB; +import org.apache.doris.rpc.BackendServiceProxy; +import org.apache.doris.rpc.RpcException; +import org.apache.doris.system.Backend; +import org.apache.doris.thrift.TStatusCode; + +import com.google.common.base.Preconditions; +import com.google.common.collect.Lists; +import com.google.common.collect.Maps; +import com.google.common.collect.Sets; +import org.apache.logging.log4j.LogManager; +import org.apache.logging.log4j.Logger; + +import java.util.Collections; +import java.util.Comparator; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.ExecutionException; +import java.util.concurrent.Future; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.TimeoutException; + +// This class is used to pull the specified tablets' columns existing on the Backend (BE) +// including regular columns and columns decomposed by variants +public class FetchRemoteTabletSchemaUtil { + private static final Logger LOG = LogManager.getLogger(FetchRemoteTabletSchemaUtil.class); + + private List<Tablet> remoteTablets; + private List<Column> tableColumns; + + public FetchRemoteTabletSchemaUtil(List<Tablet> tablets) { + this.remoteTablets = tablets; + this.tableColumns = Lists.newArrayList(); + } + + public List<Column> fetch() { + // 1. Find which Backend (BE) servers the tablets are on + Preconditions.checkNotNull(remoteTablets); + Map<Long, Set<Long>> beIdToTabletId = Maps.newHashMap(); + for (Tablet tablet : remoteTablets) { + for (Replica replica : tablet.getReplicas()) { + // only need alive replica + if (replica.isAlive()) { + Set<Long> tabletIds = beIdToTabletId.computeIfAbsent( + replica.getBackendId(), k -> Sets.newHashSet()); + tabletIds.add(tablet.getId()); + } + } + } + + // 2. Randomly select 2 Backend (BE) servers to act as coordinators. Review Comment: The logic for schema merge is implemented in the BE (Backend), where different BEs need to merge to obtain a final schema. Implementing this logic in the FE (Frontend) would be somewhat redundant. Using a Coordinator approach is simpler and more direct, and the extra RPC (Remote Procedure Call) doesn't add significant overhead -- 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: commits-unsubscr...@doris.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@doris.apache.org For additional commands, e-mail: commits-h...@doris.apache.org
