[FLINK-21713] Correct function CURRENT_TIMESTAMP/CURRENT_TIME/CURRENT_DATE/NOW/LOCALTIME/LOCALTIMESTAMP

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

Environment

The value of time function CURRENT_TIMESTAMP and NOW() are corrected from UTC time with `TIMESTAMP` type to epoch time with `TIMESTAMP_LTZ` type. Time function LOCALTIME, LOCALTIMESTAMP, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP and NOW() are corrected from evaluates for per record in batch mode to evaluate once at query-start for batch job.

Release Note

The value of time function CURRENT_TIMESTAMP and NOW() are corrected from UTC time with `TIMESTAMP` type to epoch time with `TIMESTAMP_LTZ` type. Time function LOCALTIME, LOCALTIMESTAMP, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP and NOW() are corrected from evaluates for per record in batch mode to evaluate once at query-start for batch job.

• Assignee: Leonard Xu
• Reporter: Leonard Xu
• Created: 10/Mar/21 11:47
• Updated: 24/Aug/22 08:50
• Resolved: 26/Mar/21 13:02

Description

1. fix the return value type as well the return value for following time functions

 

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

 

2. The following functions' evaluation is depend on execution mode

• LOCALTIME
• LOCALTIMESTAMP
• CURRENT_DATE
• CURRENT_TIME
• CURRENT_TIMESTAMP
• NOW()

Flink evaluates above time function values according to execution mode, i.e. Flink evaluates time function value for row level in Streaming mode, evaluates the time function value at query start for batch mode.

Issue Links

• links to: GitHub Pull Request #15303