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Hadoop QA commented on HBASE-21418: ----------------------------------- | (x) *{color:red}-1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || | {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 0m 36s{color} | {color:blue} Docker mode activated. {color} | || || || || {color:brown} Prechecks {color} || | {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m 5s{color} | {color:blue} Findbugs executables are not available. {color} | | {color:green}+1{color} | {color:green} hbaseanti {color} | {color:green} 0m 0s{color} | {color:green} Patch does not have any anti-patterns. {color} | | {color:green}+1{color} | {color:green} @author {color} | {color:green} 0m 0s{color} | {color:green} The patch does not contain any @author tags. {color} | | {color:green}+1{color} | {color:green} test4tests {color} | {color:green} 0m 0s{color} | {color:green} The patch appears to include 2 new or modified test files. {color} | || || || || {color:brown} branch-1.2 Compile Tests {color} || | {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 2m 38s{color} | {color:blue} Maven dependency ordering for branch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 8m 28s{color} | {color:green} branch-1.2 passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m 16s{color} | {color:green} branch-1.2 passed with JDK v1.8.0_181 {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 52s{color} | {color:green} branch-1.2 passed with JDK v1.7.0_191 {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m 44s{color} | {color:green} branch-1.2 passed {color} | | {color:green}+1{color} | {color:green} shadedjars {color} | {color:green} 2m 31s{color} | {color:green} branch has no errors when building our shaded downstream artifacts. {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 50s{color} | {color:green} branch-1.2 passed with JDK v1.8.0_181 {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 56s{color} | {color:green} branch-1.2 passed with JDK v1.7.0_191 {color} | || || || || {color:brown} Patch Compile Tests {color} || | {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m 11s{color} | {color:blue} Maven dependency ordering for patch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m 30s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 45s{color} | {color:green} the patch passed with JDK v1.8.0_181 {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m 45s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m 51s{color} | {color:green} the patch passed with JDK v1.7.0_191 {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m 51s{color} | {color:green} the patch passed {color} | | {color:red}-1{color} | {color:red} checkstyle {color} | {color:red} 1m 16s{color} | {color:red} hbase-server: The patch generated 13 new + 164 unchanged - 1 fixed = 177 total (was 165) {color} | | {color:green}+1{color} | {color:green} whitespace {color} | {color:green} 0m 0s{color} | {color:green} The patch has no whitespace issues. {color} | | {color:green}+1{color} | {color:green} shadedjars {color} | {color:green} 2m 21s{color} | {color:green} patch has no errors when building our shaded downstream artifacts. {color} | | {color:green}+1{color} | {color:green} hadoopcheck {color} | {color:green} 8m 29s{color} | {color:green} Patch does not cause any errors with Hadoop 2.4.1 2.5.2 2.6.5 2.7.4. {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 39s{color} | {color:green} the patch passed with JDK v1.8.0_181 {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m 53s{color} | {color:green} the patch passed with JDK v1.7.0_191 {color} | || || || || {color:brown} Other Tests {color} || | {color:green}+1{color} | {color:green} unit {color} | {color:green} 2m 2s{color} | {color:green} hbase-client in the patch passed. {color} | | {color:red}-1{color} | {color:red} unit {color} | {color:red}140m 51s{color} | {color:red} hbase-server in the patch failed. {color} | | {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m 41s{color} | {color:green} The patch does not generate ASF License warnings. {color} | | {color:black}{color} | {color:black} {color} | {color:black}181m 41s{color} | {color:black} {color} | \\ \\ || Reason || Tests || | Failed junit tests | hadoop.hbase.replication.regionserver.TestRegionReplicaReplicationEndpoint | | | hadoop.hbase.mapreduce.TestLoadIncrementalHFilesUseSecurityEndPoint | | | hadoop.hbase.master.TestAssignmentManagerOnCluster | \\ \\ || Subsystem || Report/Notes || | Docker | Client=17.05.0-ce Server=17.05.0-ce Image:yetus/hbase:34a9b27 | | JIRA Issue | HBASE-21418 | | JIRA Patch URL | https://issues.apache.org/jira/secure/attachment/12946565/HBASE-21418.branch-1.2.001.patch | | Optional Tests | dupname asflicense javac javadoc unit findbugs shadedjars hadoopcheck hbaseanti checkstyle compile | | uname | Linux caf953f2bef6 4.4.0-138-generic #164-Ubuntu SMP Tue Oct 2 17:16:02 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux | | Build tool | maven | | Personality | /home/jenkins/jenkins-slave/workspace/PreCommit-HBASE-Build@2/component/dev-support/hbase-personality.sh | | git revision | branch-1.2 / 1add8f1 | | maven | version: Apache Maven 3.0.5 | | Default Java | 1.7.0_191 | | Multi-JDK versions | /usr/lib/jvm/java-8-openjdk-amd64:1.8.0_181 /usr/lib/jvm/java-7-openjdk-amd64:1.7.0_191 | | checkstyle | https://builds.apache.org/job/PreCommit-HBASE-Build/14928/artifact/patchprocess/diff-checkstyle-hbase-server.txt | | unit | https://builds.apache.org/job/PreCommit-HBASE-Build/14928/artifact/patchprocess/patch-unit-hbase-server.txt | | Test Results | https://builds.apache.org/job/PreCommit-HBASE-Build/14928/testReport/ | | Max. process+thread count | 4413 (vs. ulimit of 10000) | | modules | C: hbase-client hbase-server U: . | | Console output | https://builds.apache.org/job/PreCommit-HBASE-Build/14928/console | | Powered by | Apache Yetus 0.8.0 http://yetus.apache.org | This message was automatically generated. > Reduce a number of reseek operations in MemstoreScanner when seek point is > close to the current row. > ---------------------------------------------------------------------------------------------------- > > Key: HBASE-21418 > URL: https://issues.apache.org/jira/browse/HBASE-21418 > Project: HBase > Issue Type: Improvement > Components: scan, Scanners > Affects Versions: 1.2.5 > Reporter: Jeongdae Kim > Assignee: Jeongdae Kim > Priority: Minor > Labels: performance > Attachments: HBASE-21418.branch-1.2.001.patch, > HBASE-21418.branch-1.2.001.patch > > > We observed “responseTooSlow” logs for Get requests in our production > clusters. even some get requests were responded after 10 seconds. > Affected get requests were done with the timerange, and target rows have many > columns that have some versions. > We reproduced this issue, and found this behavior happens only when scanning > in the memstore. after flushing the HStore, this slow response issue for Get > disappeared and all same get requests are responded very quickly. > > We investigated this case, and found this performance difference between > memstore scanner and hfile scanner is caused by the number of reseek > operations executed while scanning. When a store scanner needs to reseek the > next column, Hfile scanner wisely decide whether it have to reseek or not by > checking the seek point is in current block, whereas memstore scanner just do > reseek without decision unlike Hfile scanner. In our case, almost all columns > in the memstore have older timestamp than scan(get)’s timerange, and so many > reseek operations occur as much as about the number of columns. This results > in increasing the response time of Get requests sporadically. > > To improve the reseek operation of the memstore scanner, i think it’s better > skipping than seeking when reseek requested, if seek point is quite close to > current cell that the scanner is pointing now.(Actually, i changed > MatchCode.SEEK_NEXT_COL to MatchCode.Skip in our case, and the response time > of Get was 6x faster than before) But we can’t decide whether seek point is > close to the current cell or not, because memstore scannner has no > information such as next block index. > Before HBASE-13109, Scan.HINT_LOOKAHEAD was introduced to handle like this > case, and it may be deprecated someday. But, i think that hint is still be > useful for the memstore scanner to try to skip first, before reseeking, and > with this option we can make reseek operations of memstore scanner smarter. > > I tested this patch in our case, and got the same result as i changed > matchcode (mentioned above). -- This message was sent by Atlassian JIRA (v7.6.3#76005)