[IMPALA-4546] Incorporate Russian/Moscow timezone changes in to the tz db

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 2.8.0
• Fix Version/s: Impala 2.9.0
• Component/s: Backend
• Labels: correctness
• Epic Link: Timestamp Compatibility
• Target Version: Impala 2.9.0
• Assignee: Taras Bobrovytsky
• Reporter: Bharath Vissapragada
• Created: 28/Nov/16 18:54
• Updated: 22/Mar/18 23:06
• Resolved: 03/Mar/17 02:22

Description

The issue in short

select to_utc_timestamp('2016-10-14 00:00:00', 'Europe/Moscow')

Expected result:
2016-10-13 21:00:00

Actual result:
2016-10-13 20:00:00

The issue here is [1]

Most Russians will move to permanent Standard Time, or “winter time”, by setting their clocks 1 hour back on October 26, 2014. This is the same date most Europeans end Daylight Saving Time (DST).
Current local time in Russia
But the Russians will only join in the setting back of the clocks this year. From then on they will remain on Standard Time (winter time) and will not be setting their clocks forward again 1 hour along with the rest of Europe in March 2015.

For longterm, we should rely on a standard tz DB rather than letting Impala handle timezone exceptions manually in the code.

Workaround: Use a custom Java UDF that runs on JDK 8u31 or greater (which has this timezone change embedded.)

[1] https://www.timeanddate.com/news/time/russia-abandons-permanent-summer-time.html