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Hudson commented on HBASE-20914: -------------------------------- Results for branch master [build #403 on builds.a.o|https://builds.apache.org/job/HBase%20Nightly/job/master/403/]: (x) *{color:red}-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/master/403//General_Nightly_Build_Report/] (x) {color:red}-1 jdk8 hadoop2 checks{color} -- For more information [see jdk8 (hadoop2) report|https://builds.apache.org/job/HBase%20Nightly/job/master/403//JDK8_Nightly_Build_Report_(Hadoop2)/] (x) {color:red}-1 jdk8 hadoop3 checks{color} -- For more information [see jdk8 (hadoop3) report|https://builds.apache.org/job/HBase%20Nightly/job/master/403//JDK8_Nightly_Build_Report_(Hadoop3)/] (/) {color:green}+1 source release artifact{color} -- See build output for details. (/) {color:green}+1 client integration test{color} > Trim Master memory usage > ------------------------ > > Key: HBASE-20914 > URL: https://issues.apache.org/jira/browse/HBASE-20914 > Project: HBase > Issue Type: Sub-task > Components: master > Reporter: stack > Assignee: stack > Priority: Major > Fix For: 3.0.0, 2.0.2, 2.2.0, 2.1.1 > > Attachments: HBASE-20914.branch-2.0.001.patch, Screen Shot 2018-07-19 > at 1.20.23 PM.png, Screen Shot 2018-07-19 at 1.20.23 PM.png, Screen Shot > 2018-07-19 at 1.38.56 PM.png, Screen Shot 2018-07-19 at 1.38.56 PM.png, > Screen Shot 2018-07-19 at 2.22.42 PM.png, Screen Shot 2018-07-19 at 2.22.42 > PM.png, Screen Shot 2018-07-19 at 2.43.42 PM.png, Screen Shot 2018-07-19 at > 2.43.42 PM.png > > > While working on the parent issue, looking at a heap from a Master tha was > running ~650 servers and > 300k regions, I tripped over some silly items in > the heap: > 1. Balancer has a regions x server matrix which takes up 18% of the Master > heap according to jxray and 40% according to eclipse. Looks like the matrix > should be regions x racks which would be much smaller (Issue came in with > HBASE-18164 Fast locality computation in balancer -Added new > LocalityCostFunction and LocalityCandidateGenerator ..). See !Screen Shot > 2018-07-19 at 1.20.23 PM.png! !Screen Shot 2018-07-19 at 1.38.56 PM.png! > 2. Duplicate Strings make up ~5% of the Master heap. Of these, ServerName > seems to be the font. Interesting is report that there 54k instances of > ServerName in this heap though there are only 650 Servers. See !Screen Shot > 2018-07-19 at 2.22.42 PM.png! > 3. ArrayDequeue initializes its internal elements array with 16 elements. We > use this in a few places. In Procedures, of which there are many in this > heap, we near never make use of this array. See !Screen Shot 2018-07-19 at > 2.43.42 PM.png! -- This message was sent by Atlassian JIRA (v7.6.3#76005)