[jira] [Commented] (HIVE-25576) Add config to parse date with older date format

["Stamatis Zampetakis (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HIVE-25576?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17752810#comment-17752810 ] 

Stamatis Zampetakis commented on HIVE-25576:
--------------------------------------------

[~ashish-kumar-sharma] I would like to take this ticket to completion. The current PR has been closed due to inactivity. I will open a new one along with some improvements that I think can be done in terms of code & tests. If you are still interested in this PR let me know and I can ping you to review it once I am done.

> Add config to parse date with older date format
> -----------------------------------------------
>
>                 Key: HIVE-25576
>                 URL: https://issues.apache.org/jira/browse/HIVE-25576
>             Project: Hive
>          Issue Type: Improvement
>    Affects Versions: 3.1.0, 3.0.0, 3.1.1, 3.1.2, 4.0.0
>            Reporter: Ashish Sharma
>            Assignee: Stamatis Zampetakis
>            Priority: Major
>              Labels: pull-request-available
>          Time Spent: 3h
>  Remaining Estimate: 0h
>
> *History*
> *Hive 1.2* - 
> VM time zone set to Asia/Bangkok
> *Query* - SELECT FROM_UNIXTIME(UNIX_TIMESTAMP('1800-01-01 00:00:00 UTC','yyyy-MM-dd HH:mm:ss z'));
> *Result* - 1800-01-01 07:00:00
> *Implementation details* - 
> SimpleDateFormat formatter = new SimpleDateFormat(pattern);
> Long unixtime = formatter.parse(textval).getTime() / 1000;
> Date date = new Date(unixtime * 1000L);
> https://docs.oracle.com/javase/8/docs/api/java/util/Date.html . In official documentation they have mention that "Unfortunately, the API for these functions was not amenable to internationalization and The corresponding methods in Date are deprecated" . Due to that this is producing wrong result
> *Master branch* - 
> set hive.local.time.zone=Asia/Bangkok;
> *Query* - SELECT FROM_UNIXTIME(UNIX_TIMESTAMP('1800-01-01 00:00:00 UTC','yyyy-MM-dd HH:mm:ss z'));
> *Result* - 1800-01-01 06:42:04
> *Implementation details* - 
> DateTimeFormatter dtformatter = new DateTimeFormatterBuilder()
>         .parseCaseInsensitive()
>         .appendPattern(pattern)
>         .toFormatter();
>     ZonedDateTime zonedDateTime = ZonedDateTime.parse(textval,dtformatter).withZoneSameInstant(ZoneId.of(timezone));
>     Long dttime = zonedDateTime.toInstant().getEpochSecond();
> *Problem*- 
> Now *SimpleDateFormat* has been replaced with *DateTimeFormatter* which is giving the correct result but it is not backword compatible. Which is causing issue at time for migration to new version. Because the older data written is using Hive 1.x or 2.x is not compatible with *DateTimeFormatter*.
> *Solution*
> Introduce an config "hive.legacy.timeParserPolicy" with following values -
> 1. *True*- use *SimpleDateFormat* 
> 2. *False*  - use *DateTimeFormatter*
> Note: apache spark also face the same issue https://issues.apache.org/jira/browse/SPARK-30668



--
This message was sent by Atlassian Jira
(v8.20.10#820010)