virajjasani commented on a change in pull request #978: HBASE-22285 A normalizer which merges small size regions with adjacen… URL: https://github.com/apache/hbase/pull/978#discussion_r362161876
########## File path: hbase-server/src/main/java/org/apache/hadoop/hbase/master/normalizer/MergeNormalizer.java ########## @@ -0,0 +1,131 @@ +/** + * + * 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.hadoop.hbase.master.normalizer; + +import java.sql.Timestamp; +import java.util.ArrayList; +import java.util.List; +import java.util.concurrent.TimeUnit; +import org.apache.hadoop.hbase.HBaseConfiguration; +import org.apache.hadoop.hbase.HBaseIOException; +import org.apache.hadoop.hbase.HConstants; +import org.apache.hadoop.hbase.TableName; +import org.apache.hadoop.hbase.client.RegionInfo; +import org.apache.yetus.audience.InterfaceAudience; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Implementation of MergeNormalizer Logic in use: + * <ol> + * <li>get all regions of a given table + * <li>get avg size S of each region (by total size of store files reported in RegionLoad) + * <li>two regions R1 and its neighbour R2 are merged, if R1 + R2 < S, and all such regions are + * returned to be merged + * <li>Otherwise, no action is performed + * </ol> + * <p> + * Region sizes are coarse and approximate on the order of megabytes. Also, empty regions (less than + * 1MB) are also merged if the age of region is > MIN_DURATION_FOR_MERGE (default 2) + * </p> + */ + [email protected] +public class MergeNormalizer extends BaseNormalizer { + private static final Logger LOG = LoggerFactory.getLogger(MergeNormalizer.class); + private static final int MIN_REGION_COUNT = 3; + + private int minRegionCount; + private static long[] skippedCount = new long[NormalizationPlan.PlanType.values().length]; + + public MergeNormalizer() { + minRegionCount = HBaseConfiguration.create().getInt("hbase.normalizer.min.region.count", 3); + } + + @Override + public void planSkipped(RegionInfo hri, NormalizationPlan.PlanType type) { + skippedCount[type.ordinal()]++; + } + + @Override + public long getSkippedCount(NormalizationPlan.PlanType type) { + return skippedCount[type.ordinal()]; + } + + @Override + public List<NormalizationPlan> computePlanForTable(TableName table) throws HBaseIOException { + List<NormalizationPlan> plans = new ArrayList<>(); + if (!shouldNormalize(table)) { + return null; + } + // atleast one of the two regions should be older than MIN_REGION_DURATION days + List<NormalizationPlan> normalizationPlans = getMergeNormalizationPlan(table); + for (NormalizationPlan plan : normalizationPlans) { + if (plan instanceof MergeNormalizationPlan) { + RegionInfo hri = ((MergeNormalizationPlan) plan).getFirstRegion(); + RegionInfo hri2 = ((MergeNormalizationPlan) plan).getSecondRegion(); + if (isOldEnoughToMerge(hri) || isOldEnoughToMerge(hri2)) { + plans.add(plan); + } + } + } + if (plans.isEmpty()) { + LOG.debug("No normalization needed, regions look good for table: {}", table); + return null; + } + return plans; + } + + private boolean isOldEnoughToMerge(RegionInfo hri) { + Timestamp currentTime = new Timestamp(System.currentTimeMillis()); + Timestamp hriTime = new Timestamp(hri.getRegionId()); + boolean isOld = + new Timestamp(hriTime.getTime() + TimeUnit.DAYS.toMillis(getMinimumDurationBeforeMerge())) + .before(currentTime); + return isOld; + } + + private boolean shouldNormalize(TableName table) { + boolean normalize = false; + if (table == null || table.isSystemTable()) { + LOG.debug("Normalization of system table {} isn't allowed", table); Review comment: table here would not be null(HMaster always calls it with non-null value), and we can remove null check from this if condition. Even if null was possible, log message would not be appropriate: `Normalization of system table null isn't allowed` `table == null` can be removed ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
