pvary commented on code in PR #10308: URL: https://github.com/apache/iceberg/pull/10308#discussion_r1608717408
########## flink/v1.19/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/MonitorSource.java: ########## @@ -0,0 +1,200 @@ +/* + * 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.iceberg.flink.maintenance.operator; + +import java.io.IOException; +import java.util.Iterator; +import org.apache.flink.api.common.typeinfo.TypeInformation; +import org.apache.flink.api.connector.source.Boundedness; +import org.apache.flink.api.connector.source.SourceReader; +import org.apache.flink.api.connector.source.SourceReaderContext; +import org.apache.flink.api.connector.source.util.ratelimit.RateLimitedSourceReader; +import org.apache.flink.api.connector.source.util.ratelimit.RateLimiter; +import org.apache.flink.api.connector.source.util.ratelimit.RateLimiterStrategy; +import org.apache.flink.core.io.SimpleVersionedSerializer; +import org.apache.flink.core.memory.DataInputDeserializer; +import org.apache.flink.core.memory.DataOutputSerializer; +import org.apache.iceberg.Snapshot; +import org.apache.iceberg.Table; +import org.apache.iceberg.flink.TableLoader; +import org.apache.iceberg.relocated.com.google.common.annotations.VisibleForTesting; +import org.apache.iceberg.relocated.com.google.common.base.MoreObjects; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** Monitors an Iceberg table for changes */ +public class MonitorSource extends SingleThreadedIteratorSource<TableChange> { + private static final Logger LOG = LoggerFactory.getLogger(MonitorSource.class); + + private final TableLoader tableLoader; + private final RateLimiterStrategy rateLimiterStrategy; + private final long maxReadBack; + + /** + * Creates a {@link org.apache.flink.api.connector.source.Source} which monitors an Iceberg table + * for changes. + * + * @param tableLoader used for accessing the table + * @param rateLimiterStrategy limits the frequency the table is checked + * @param maxReadBack sets the number of snapshots read before stopping change collection + */ + public MonitorSource( + TableLoader tableLoader, RateLimiterStrategy rateLimiterStrategy, long maxReadBack) { + Preconditions.checkNotNull(tableLoader, "Table loader should no be null"); + Preconditions.checkNotNull(rateLimiterStrategy, "Rate limiter strategy should no be null"); + Preconditions.checkArgument(maxReadBack > 0, "Need to read at least 1 snapshot to work"); + + this.tableLoader = tableLoader; + this.rateLimiterStrategy = rateLimiterStrategy; + this.maxReadBack = maxReadBack; + } + + @Override + public Boundedness getBoundedness() { + return Boundedness.CONTINUOUS_UNBOUNDED; + } + + @Override + public TypeInformation<TableChange> getProducedType() { + return TypeInformation.of(TableChange.class); + } + + @Override + Iterator<TableChange> createIterator() { + return new SchedulerEventIterator(tableLoader, null, maxReadBack); + } + + @Override + SimpleVersionedSerializer<Iterator<TableChange>> getIteratorSerializer() { + return new SchedulerEventIteratorSerializer(tableLoader, maxReadBack); + } + + @Override + public SourceReader<TableChange, GlobalSplit<TableChange>> createReader( + SourceReaderContext readerContext) throws Exception { + RateLimiter rateLimiter = rateLimiterStrategy.createRateLimiter(1); + return new RateLimitedSourceReader<>(super.createReader(readerContext), rateLimiter); + } + + /** The Iterator which returns the latest changes on an Iceberg table. */ + @VisibleForTesting + static class SchedulerEventIterator implements Iterator<TableChange> { + private Long lastSnapshotId; + private final long maxReadBack; + private final Table table; + + SchedulerEventIterator(TableLoader tableLoader, Long lastSnapshotId, long maxReadBack) { + this.lastSnapshotId = lastSnapshotId; + this.maxReadBack = maxReadBack; + tableLoader.open(); + this.table = tableLoader.loadTable(); + } + + @Override + public boolean hasNext() { + return true; + } + + @Override + public TableChange next() { + try { + table.refresh(); + Snapshot currentSnapshot = table.currentSnapshot(); + Long current = currentSnapshot != null ? currentSnapshot.snapshotId() : null; + Long checking = current; + TableChange event = new TableChange(0, 0, 0L, 0L, 0); + long readBack = 0; + while (checking != null && !checking.equals(lastSnapshotId) && ++readBack <= maxReadBack) { Review Comment: The Monitor/TriggerManager is the same for all of the Maintenance Task, they should be kept generic. The compaction jobs itself could store the state of the previous runs if we decide it is worth the complexity (list of the candidate, but not yet compacted files, snapshots which are scanned / snapshots which are not yet scanned) The savings could be significant, if this is an - Append only table - Only a few partitions are written It is not optional, if any of the following is true: - The goal is delete file removal - any V2 table - The distribution of the partitions are even Do you think that we can continue this discussion independently of the MonitorSource? -- 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. 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