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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} 1m 14s{color} | {color:blue} Maven dependency ordering for branch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 5m 35s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 2m 1s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m 15s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 1m 33s{color} | {color:green} master passed {color} | || || || || {color:brown} Patch Compile Tests {color} || | {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m 21s{color} | {color:blue} Maven dependency ordering for patch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 2m 18s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 1m 54s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 1m 54s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 1m 13s{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} 21m 2s{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 / e120bd8 | | 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-8250/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, HIVE-18149.03wip01.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)