richardstartin commented on a change in pull request #7956: URL: https://github.com/apache/pinot/pull/7956#discussion_r774501653
########## File path: pinot-controller/src/main/java/org/apache/pinot/controller/helix/core/realtime/segment/SegmentFlushThresholdComputer.java ########## @@ -0,0 +1,184 @@ +/** + * 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.pinot.controller.helix.core.realtime.segment; + +import java.util.List; +import javax.annotation.Nullable; +import org.apache.pinot.common.metadata.segment.SegmentZKMetadata; +import org.apache.pinot.common.utils.LLCSegmentName; +import org.apache.pinot.spi.stream.PartitionGroupMetadata; +import org.apache.pinot.spi.stream.PartitionLevelStreamConfig; +import org.apache.pinot.spi.utils.TimeUtils; + +import static org.apache.pinot.controller.helix.core.realtime.segment.SegmentSizeBasedFlushThresholdUpdater.LOGGER; + + +public class SegmentFlushThresholdComputer { + public static final int MINIMUM_NUM_ROWS_THRESHOLD = 10_000; + static final double CURRENT_SEGMENT_RATIO_WEIGHT = 0.1; + static final double PREVIOUS_SEGMENT_RATIO_WEIGHT = 0.9; + static final double ROWS_MULTIPLIER_WHEN_TIME_THRESHOLD_HIT = 1.1; + + // num rows to segment size ratio of last committed segment for this table + private double _latestSegmentRowsToSizeRatio; + private final Clock _clock; + + public SegmentFlushThresholdComputer() { + this(new SystemClock(), 0); + } + + public SegmentFlushThresholdComputer(Clock clock, double latestSegmentRowsToSizeRatio) { + this._clock = clock; + this._latestSegmentRowsToSizeRatio = latestSegmentRowsToSizeRatio; + } + + public SegmentFlushThresholdComputer(Clock clock) { + this(clock, 0); + } + + double getLatestSegmentRowsToSizeRatio() { + return _latestSegmentRowsToSizeRatio; + } + + public int computeThreshold(PartitionLevelStreamConfig streamConfig, + CommittingSegmentDescriptor committingSegmentDescriptor, + @Nullable SegmentZKMetadata committingSegmentZKMetadata, + List<PartitionGroupMetadata> partitionGroupMetadataList, String newSegmentName) { + final long desiredSegmentSizeBytes = streamConfig.getFlushThresholdSegmentSizeBytes(); + final long optimalSegmentSizeBytesMin = desiredSegmentSizeBytes / 2; + final double optimalSegmentSizeBytesMax = desiredSegmentSizeBytes * 1.5; + + if (committingSegmentZKMetadata == null) { // first segment of the partition, hence committing segment is null + if (_latestSegmentRowsToSizeRatio > 0) { // new partition group added case + long targetSegmentNumRows = (long) (desiredSegmentSizeBytes * _latestSegmentRowsToSizeRatio); + targetSegmentNumRows = capNumRowsIfOverflow(targetSegmentNumRows); + LOGGER.info( + "Committing segment zk metadata is not available, using prev ratio {}, setting rows threshold for {} as {}", + _latestSegmentRowsToSizeRatio, newSegmentName, targetSegmentNumRows); + return (int) targetSegmentNumRows; + } else { + final int autotuneInitialRows = streamConfig.getFlushAutotuneInitialRows(); + LOGGER.info( + "Committing segment zk metadata is not available, setting threshold for {} as {}", newSegmentName, + autotuneInitialRows); + return autotuneInitialRows; + } + } + + final long committingSegmentSizeBytes = committingSegmentDescriptor.getSegmentSizeBytes(); + if (committingSegmentSizeBytes <= 0) { // repair segment case + final int targetNumRows = committingSegmentZKMetadata.getSizeThresholdToFlushSegment(); + LOGGER.info( + "Committing segment size is not available, setting thresholds from previous segment for {} as {}", + newSegmentName, targetNumRows); + return targetNumRows; + } + + final long timeConsumed = _clock.currentTimeMillis() - committingSegmentZKMetadata.getCreationTime(); + final long numRowsConsumed = committingSegmentZKMetadata.getTotalDocs(); + final int numRowsThreshold = committingSegmentZKMetadata.getSizeThresholdToFlushSegment(); + LOGGER.info( + "{}: Data from committing segment: Time {} numRows {} threshold {} segmentSize(bytes) {}", + newSegmentName, TimeUtils.convertMillisToPeriod(timeConsumed), numRowsConsumed, numRowsThreshold, + committingSegmentSizeBytes); + + double currentRatio = (double) numRowsConsumed / committingSegmentSizeBytes; + // Compute segment size to rows ratio only from the lowest available partition id. + // If we consider all partitions then it is likely that we will assign a much higher weight to the most + // recent trend in the table (since it is usually true that all partitions of the same table follow more or + // less same characteristics at any one point in time). + // However, when we start a new table or change controller mastership, we can have any partition completing first. + // It is best to learn the ratio as quickly as we can, so we allow any partition to supply the value. + int smallestAvailablePartitionGroupId = + partitionGroupMetadataList.stream().mapToInt(PartitionGroupMetadata::getPartitionGroupId).min() + .orElseGet(() -> 0); Review comment: I know this is just code moved from one place to another but `.orElse(0)` would be better -- This is an automated message from the Apache Git Service. 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