[ https://issues.apache.org/jira/browse/HIVE-21291?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16814005#comment-16814005 ]
Hive QA commented on HIVE-21291: -------------------------------- | (/) *{color:green}+1 overall{color}* | \\ \\ || Vote || Subsystem || Runtime || Comment || || || || || {color:brown} Prechecks {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 51s{color} | {color:blue} Maven dependency ordering for branch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 7m 10s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 7m 50s{color} | {color:green} master passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 3m 0s{color} | {color:green} master passed {color} | | {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 0m 41s{color} | {color:blue} serde in master has 197 extant Findbugs warnings. {color} | | {color:blue}0{color} | {color:blue} findbugs {color} | {color:blue} 4m 9s{color} | {color:blue} ql in master has 2258 extant Findbugs warnings. {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 8m 2s{color} | {color:green} master passed {color} | || || || || {color:brown} Patch Compile Tests {color} || | {color:blue}0{color} | {color:blue} mvndep {color} | {color:blue} 0m 23s{color} | {color:blue} Maven dependency ordering for patch {color} | | {color:green}+1{color} | {color:green} mvninstall {color} | {color:green} 8m 38s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} compile {color} | {color:green} 7m 53s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javac {color} | {color:green} 7m 53s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} checkstyle {color} | {color:green} 2m 59s{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} findbugs {color} | {color:green} 5m 5s{color} | {color:green} the patch passed {color} | | {color:green}+1{color} | {color:green} javadoc {color} | {color:green} 7m 55s{color} | {color:green} the patch passed {color} | || || || || {color:brown} Other Tests {color} || | {color:green}+1{color} | {color:green} asflicense {color} | {color:green} 0m 17s{color} | {color:green} The patch does not generate ASF License warnings. {color} | | {color:black}{color} | {color:black} {color} | {color:black} 66m 43s{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 3.16.43-2+deb8u5 (2017-09-19) x86_64 GNU/Linux | | Build tool | maven | | Personality | /data/hiveptest/working/yetus_PreCommit-HIVE-Build-16903/dev-support/hive-personality.sh | | git revision | master / 928f3d6 | | Default Java | 1.8.0_111 | | findbugs | v3.0.0 | | modules | C: serde ql . U: . | | Console output | http://104.198.109.242/logs//PreCommit-HIVE-Build-16903/yetus.txt | | Powered by | Apache Yetus http://yetus.apache.org | This message was automatically generated. > Restore historical way of handling timestamps in Avro while keeping the new > semantics at the same time > ------------------------------------------------------------------------------------------------------ > > Key: HIVE-21291 > URL: https://issues.apache.org/jira/browse/HIVE-21291 > Project: Hive > Issue Type: Sub-task > Reporter: Zoltan Ivanfi > Assignee: Karen Coppage > Priority: Major > Attachments: HIVE-21291.1.patch, HIVE-21291.2.patch, > HIVE-21291.3.patch, HIVE-21291.4.patch, HIVE-21291.4.patch > > > This sub-task is for implementing the Avro-specific parts of the following > plan: > h1. Problem > Historically, the semantics of the TIMESTAMP type in Hive depended on the > file format. Timestamps in Avro, Parquet and RCFiles with a binary SerDe had > _Instant_ semantics, while timestamps in ORC, textfiles and RCFiles with a > text SerDe had _LocalDateTime_ semantics. > The Hive community wanted to get rid of this inconsistency and have > _LocalDateTime_ semantics in Avro, Parquet and RCFiles with a binary SerDe as > well. *Hive 3.1 turned off normalization to UTC* to achieve this. While this > leads to the desired new semantics, it also leads to incorrect results when > new Hive versions read timestamps written by old Hive versions or when old > Hive versions or any other component not aware of this change (including > legacy Impala and Spark versions) read timestamps written by new Hive > versions. > h1. Solution > To work around this issue, Hive *should restore the practice of normalizing > to UTC* when writing timestamps to Avro, Parquet and RCFiles with a binary > SerDe. In itself, this would restore the historical _Instant_ semantics, > which is undesirable. In order to achieve the desired _LocalDateTime_ > semantics in spite of normalizing to UTC, newer Hive versions should record > the session-local local time zone in the file metadata fields serving > arbitrary key-value storage purposes. > When reading back files with this time zone metadata, newer Hive versions (or > any other new component aware of this extra metadata) can achieve > _LocalDateTime_ semantics by *converting from UTC to the saved time zone > (instead of to the local time zone)*. Legacy components that are unaware of > the new metadata can read the files without any problem and the timestamps > will show the historical Instant behaviour to them. -- This message was sent by Atlassian JIRA (v7.6.3#76005)