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Hudson commented on HBASE-24428: -------------------------------- Results for branch branch-2 [build #2683 on builds.a.o|https://builds.apache.org/job/HBase%20Nightly/job/branch-2/2683/]: (/) *{color:green}+1 overall{color}* ---- details (if available): (/) {color:green}+1 general checks{color} -- For more information [see general report|https://builds.apache.org/job/HBase%20Nightly/job/branch-2/2683/General_20Nightly_20Build_20Report/] (/) {color:green}+1 jdk8 hadoop2 checks{color} -- For more information [see jdk8 (hadoop2) report|https://builds.apache.org/job/HBase%20Nightly/job/branch-2/2683/JDK8_20Nightly_20Build_20Report_20_28Hadoop2_29/] (/) {color:green}+1 jdk8 hadoop3 checks{color} -- For more information [see jdk8 (hadoop3) report|https://builds.apache.org/job/HBase%20Nightly/job/branch-2/2683/JDK8_20Nightly_20Build_20Report_20_28Hadoop3_29/] (/) {color:green}+1 jdk11 hadoop3 checks{color} -- For more information [see jdk11 report|https://builds.apache.org/job/HBase%20Nightly/job/branch-2/2683/JDK11_20Nightly_20Build_20Report_20_28Hadoop3_29/] (/) {color:green}+1 source release artifact{color} -- See build output for details. (/) {color:green}+1 client integration test{color} > Priority compaction for recently split daughter regions > ------------------------------------------------------- > > Key: HBASE-24428 > URL: https://issues.apache.org/jira/browse/HBASE-24428 > Project: HBase > Issue Type: Improvement > Components: Compaction > Reporter: Andrew Kyle Purtell > Assignee: Viraj Jasani > Priority: Major > Fix For: 3.0.0-alpha-1, 2.3.0, 1.7.0, 2.2.5 > > > We observe that under hotspotting conditions that splitting will proceed very > slowly and the "_Cannot split region due to reference files being there_" log > line will be logged excessively. (branch-1 based production.) This is because > after a region is split it must be compacted before it can be split again. > Reference files must be replaced by real HFiles, normal housekeeping > performed during compaction. However if the regionserver is under excessive > load, its compaction queues may become deep. The daughters of a recently > split hotspotting region may themselves continue to hotspot and will rapidly > need to split again. If the scheduled compaction work to remove/replace > reference files is queued hundreds or thousands of compaction queue elements > behind current, the recently split daughter regions will not be able to split > again for a long time and may grow very large, producing additional > complications (very large regions, very deep replication queues). > To help avoid this condition we should prioritize the compaction of recently > split daughter regions. Compaction requests include a {{priority}} field and > CompactionRequest implements a comparator that sorts by this field. We > already detect when a compaction request involves a region that has reference > files, to ensure that it gets selected to be eligible for compaction, but we > do not seem to prioritize the requests for post-split housekeeping. Split > work should be placed at the top of the queue. Ensure that this is happening. -- This message was sent by Atlassian Jira (v8.3.4#803005)