feat!: parsing local timestamp

[v0y4g3r]

I hereby agree to the terms of the GreptimeDB CLA

What's changed and what's your intention?

This PR changes the behavior of parsing timestamp/datetime literals without explict time zone info, according to system time zone (inherently from TZ env variable when GreptimeDB instance runs).

For example:

• 1970-01-01 00:00:00+0000 will be parsed to 0 in unix timestamp, since it has explicit time offset 0
• 1970-01-01 08:00:00+0800 will be parsed to 0 in unix timestamp, since it has explicit time offset +0800
• 1970-01-01 08:00:00 will be parsed to 0 if GreptimeDB instance is running in CST time zone (UTC+8) and 14400 if running in Asia/Dubai time zone (UTC+4)

This PR also adds time zone identifier to DateTime formatted string.

mysql> CREATE table demo (ts TIMESTAMP(6) TIME INDEX, cnt INT);
Query OK, 0 rows affected (0.05 sec)

# Insert timestamp without time zone info, it will be convert to local timestamp.
mysql> insert into demo(ts,cnt) values ('2023-04-04 08:00:00.52', 1);
Query OK, 1 row affected (0.00 sec)

# queries also format time into local time zone.
mysql> select * from demo;
+------------------------------+------+
| ts                           | cnt  |
+------------------------------+------+
| 2023-04-04 08:00:00.520+0800 |    1 |
+------------------------------+------+

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.

Refer to a related PR or issue link (optional)

#1319

[codecov]

Codecov Report

Merging #1352 (93eea3f) into develop (29c6155) will decrease coverage by 0.41%.
The diff coverage is 98.75%.

@@             Coverage Diff             @@
##           develop    #1352      +/-   ##
===========================================
- Coverage    85.48%   85.08%   -0.41%     
===========================================
  Files          514      514              
  Lines        77414    77523     +109     
===========================================
- Hits         66181    65964     -217     
- Misses       11233    11559     +326     

[waynexia]

Looking good 👍

[sunng87]

For existing users this can be a breaking change: the default time zoned just changed from UTC to local. We need to address this behaviour in changelog and guide them to set TZ if needed.

[evenyag]

👍 Nice job, my timestamp master @v0y4g3r