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https://issues.apache.org/jira/browse/HBASE-21418?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16835033#comment-16835033
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HBase QA commented on HBASE-21418:
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| (x) *{color:red}-1 overall{color}* |
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|| Vote || Subsystem || Runtime || Comment ||
| {color:blue}0{color} | {color:blue} reexec {color} | {color:blue} 1m
7s{color} | {color:blue} Docker mode activated. {color} |
|| || || || {color:brown} Prechecks {color} ||
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m
1s{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 1 new or modified test
files. {color} |
|| || || || {color:brown} branch-1.2 Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 1m
39s{color} | {color:blue} Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 7m
24s{color} | {color:green} branch-1.2 passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m
10s{color} | {color:green} branch-1.2 passed with JDK v1.8.0_212 {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
55s{color} | {color:green} branch-1.2 passed with JDK v1.7.0_222 {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m
51s{color} | {color:green} branch-1.2 passed {color} |
| {color:green}+1{color} | {color:green} shadedjars {color} | {color:green} 2m
40s{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
53s{color} | {color:green} branch-1.2 passed with JDK v1.8.0_212 {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
53s{color} | {color:green} branch-1.2 passed with JDK v1.7.0_222 {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m
10s{color} | {color:blue} Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 1m
26s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
44s{color} | {color:green} the patch passed with JDK v1.8.0_212 {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m
44s{color} | {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green} 0m
50s{color} | {color:green} the patch passed with JDK v1.7.0_222 {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green} 0m
50s{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 16 new + 377
unchanged - 4 fixed = 393 total (was 381) {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
23s{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 30s{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_212 {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 0m
57s{color} | {color:green} the patch passed with JDK v1.7.0_222 {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:green}+1{color} | {color:green} unit {color} | {color:green}120m
8s{color} | {color:green} hbase-server in the patch passed. {color} |
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m
40s{color} | {color:green} The patch does not generate ASF License warnings.
{color} |
| {color:black}{color} | {color:black} {color} | {color:black}159m 32s{color} |
{color:black} {color} |
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|| Subsystem || Report/Notes ||
| Docker | Client=17.05.0-ce Server=17.05.0-ce base:
https://builds.apache.org/job/PreCommit-HBASE-Build/263/artifact/patchprocess/Dockerfile
|
| JIRA Issue | HBASE-21418 |
| JIRA Patch URL |
https://issues.apache.org/jira/secure/attachment/12947549/HBASE-21418.branch-1.2.002.patch
|
| Optional Tests | dupname asflicense javac javadoc unit findbugs
shadedjars hadoopcheck hbaseanti checkstyle compile |
| uname | Linux e3e4d35fc810 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 | dev-support/hbase-personality.sh |
| git revision | branch-1.2 / af250d2 |
| maven | version: Apache Maven 3.0.5 |
| Default Java | 1.7.0_222 |
| Multi-JDK versions | /usr/lib/jvm/java-8-openjdk-amd64:1.8.0_212
/usr/lib/jvm/java-7-openjdk-amd64:1.7.0_222 |
| checkstyle |
https://builds.apache.org/job/PreCommit-HBASE-Build/263/artifact/patchprocess/diff-checkstyle-hbase-server.txt
|
| Test Results |
https://builds.apache.org/job/PreCommit-HBASE-Build/263/testReport/ |
| Max. process+thread count | 4372 (vs. ulimit of 10000) |
| modules | C: hbase-client hbase-server U: . |
| Console output |
https://builds.apache.org/job/PreCommit-HBASE-Build/263/console |
| Powered by | Apache Yetus 0.9.0 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: 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, HBASE-21418.branch-1.2.002.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).
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