[FLINK-21714] Use TIMESTAMP_LTZ as return type for function PROCTIME()

• Type: Sub-task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.13.0
• Component/s: Table SQL / API
• Labels: pull-request-available

Release Note

Before Flink 1.13, the function return type of `PROCTIME()` is `TIMESTAMP`, and the return value is the `TIMESTAMP` in UTC time zone,
e.g. the wall-clock shows `2021-03-01 12:00:00` at Shanghai, however the `PROCTIME()` displays `2021-03-01 04:00:00` which is wrong.
Flink 1.13 fixes this issue and uses `TIMESTAMP_LTZ` type as return type of `PROCTIME()`, users don't need to deal time zone problems anymore.

• Assignee: Leonard Xu
• Reporter: Leonard Xu
• Created: 10/Mar/21 11:52
• Updated: 24/Apr/23 03:03
• Resolved: 23/Apr/21 13:00

Description

When users use a PROCTIME() in SQL, the return value of PROCTIME() has a timezone offset with the wall-clock time in users' local time zone, users need to add their local time zone offset manually to get expected local timestamp(e.g: Users in Germany need to +1h to get expected local timestamp). 

This issue to correct PROCTIME()  function

function	existed problem	current behavior	proposed changes
PROCTIME()	returns UTC timestamp, but user expects current timestamp in session time zone	return type: TIMESTAMP  PROCTIME #session timezone: UTC 2020-12-28 23:52:52 #session timezone: UTC+8 2020-12-28 23:52:52	return current timestamp in session time zone for PROCTIME(), the return type should be TIMESTAMP  WITH LOCAL TIME ZONE *PROCTIME* #session timezone: UTC 2020-12-28 23:52:52 #session timezone: UTC+8 2020-12-29 07:52:52

Issue Links

• links to: GitHub Pull Request #15280