hive-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Hive QA (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HIVE-18149) Stats: rownum estimation from datasize underestimates in most cases
Date Sat, 09 Dec 2017 16:53:02 GMT

    [ https://issues.apache.org/jira/browse/HIVE-18149?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16284829#comment-16284829
] 

Hive QA commented on HIVE-18149:
--------------------------------

| (/) *{color:green}+1 overall{color}* |
\\
\\
|| Vote || Subsystem || Runtime || Comment ||
|| || || || {color:brown} Prechecks {color} ||
| {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue}  0m  0s{color} | {color:blue}
Findbugs executables are not available. {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:brown} master Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m 56s{color} | {color:blue}
Maven dependency ordering for branch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green}  5m 26s{color}
| {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  1m 49s{color} |
{color:green} master passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  1m 11s{color}
| {color:green} master passed {color} |
| {color:green}+1{color} | {color:green} javadoc {color} | {color:green}  1m 29s{color} |
{color:green} master passed {color} |
|| || || || {color:brown} Patch Compile Tests {color} ||
| {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue}  0m 20s{color} | {color:blue}
Maven dependency ordering for patch {color} |
| {color:green}+1{color} | {color:green} mvninstall {color} | {color:green}  2m 14s{color}
| {color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} compile {color} | {color:green}  1m 52s{color} |
{color:green} the patch passed {color} |
| {color:green}+1{color} | {color:green} javac {color} | {color:green}  1m 52s{color} | {color:green}
the patch passed {color} |
| {color:green}+1{color} | {color:green} checkstyle {color} | {color:green}  1m 11s{color}
| {color:green} the patch passed {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} javadoc {color} | {color:green}  1m 32s{color} |
{color:green} the patch passed {color} |
|| || || || {color:brown} Other Tests {color} ||
| {color:green}+1{color} | {color:green} asflicense {color} | {color:green}  0m 12s{color}
| {color:green} The patch does not generate ASF License warnings. {color} |
| {color:black}{color} | {color:black} {color} | {color:black} 19m 55s{color} | {color:black}
{color} |
\\
\\
|| Subsystem || Report/Notes ||
| Optional Tests |  asflicense  javac  javadoc  findbugs  checkstyle  compile  |
| uname | Linux hiveptest-server-upstream 3.16.0-4-amd64 #1 SMP Debian 3.16.36-1+deb8u1 (2016-09-03)
x86_64 GNU/Linux |
| Build tool | maven |
| Personality | /data/hiveptest/working/yetus/dev-support/hive-personality.sh |
| git revision | master / 5bbd864 |
| Default Java | 1.8.0_111 |
| modules | C: common ql contrib itests/hive-blobstore U: . |
| Console output | http://104.198.109.242/logs//PreCommit-HIVE-Build-8164/yetus.txt |
| Powered by | Apache Yetus    http://yetus.apache.org |


This message was automatically generated.



> Stats: rownum estimation from datasize underestimates in most cases
> -------------------------------------------------------------------
>
>                 Key: HIVE-18149
>                 URL: https://issues.apache.org/jira/browse/HIVE-18149
>             Project: Hive
>          Issue Type: Sub-task
>          Components: Statistics
>            Reporter: Zoltan Haindrich
>            Assignee: Zoltan Haindrich
>         Attachments: HIVE-18149.01.patch, HIVE-18149.01wip01.patch, HIVE-18149.02.patch
>
>
> rownum estimation is based on the following fact as of now:
> * datasize being used from the following sources:
> ** basicstats aggregates the loaded "on-heap" row sizes ; other readers are able to give
"raw size" estimation - I've checked orc; but I'm sure others will do the same....api docs
are a bit vague about the methods purpose...
> ** if the basicstats level info is not available; the filesystem level "file-size-sums"
are used as the "raw data size" ; which is multiplied by the [deserialization ratio|https://github.com/apache/hive/blob/d9924ab3e285536f7e2cc15ecbea36a78c59c66d/ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUtils.java#L261]
; which is currently 1.
> the problem with all of this is that deser factor is 1; and that rowsize counts in the
online object headers..
> example; 20 rows are loaded into a partition [columnstats_partlvl_dp.q|https://github.com/apache/hive/blob/d9924ab3e285536f7e2cc15ecbea36a78c59c66d/ql/src/test/queries/clientpositive/columnstats_partlvl_dp.q#L7]
> after HIVE-18108 [this explain|https://github.com/apache/hive/blob/d9924ab3e285536f7e2cc15ecbea36a78c59c66d/ql/src/test/queries/clientpositive/columnstats_partlvl_dp.q#L25]
will estimate the rowsize of the table to be 404 bytes; however the 20 rows of text is only
169 bytes...so it ends up with 0 rows...



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)

Mime
View raw message