Introduce use_legacy_datetime_code option for MySQL.

[hiroyuki-sato]

Fix #103

Summaries

This is a PR for embulk-input-mysql plugin.

What is the problem to solve.

This change returns correctly time(server side time) even if client and server timezone is different.

How the existing implementation works.

Return incorrectly time if client and server timezone is different.
A user need to set option { useLegacyDatetimeCode: false } explicitly.

Proposed change

• Introduce new option use_legacy_datetime_code: (default: false)
• This change does not change current behavior if server and client use same timezone.

Reproduce procedure

If timezone parameter is a difference between server and client,
latest version(0.8.18) return wrong value.

Proposed change return it properly.

Prepare test.

mysql> show variables like '%time_zone%';
+------------------+--------+
| Variable_name    | Value  |
+------------------+--------+
| system_time_zone | UTC    |
| time_zone        | SYSTEM |
+------------------+--------+
2 rows in set (0.00 sec)

mysql> select * from time_test;
+----+---------------------+---------------------+
| id | date_time           | time_stamp          |
+----+---------------------+---------------------+
|  1 | 2017-04-24 09:58:19 | 2017-04-24 09:58:19 |
+----+---------------------+---------------------+
1 row in set (0.01 sec)

create table time_test (id int not null, date_time datetime not null, time_stamp timestamp not null);
insert into time_test values(1,now(),now());

mysql> show fields from time_test;
+------------+-----------+------+-----+-------------------+-----------------------------+
| Field      | Type      | Null | Key | Default           | Extra                       |
+------------+-----------+------+-----+-------------------+-----------------------------+
| id         | int(11)   | NO   |     | NULL              |                             |
| date_time  | datetime  | NO   |     | NULL              |                             |
| time_stamp | timestamp | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
+------------+-----------+------+-----+-------------------+-----------------------------+
3 rows in set (0.00 sec)

Client timezone is JST (+09:00)

Latest version(0.8.18) behavior

without option

in:
  type: mysql
  table: time_test
  host: localhost
#  options: { useLegacyDatetimeCode: false }
  user: xxxx
  password: xxxx
  database: embulk_test

return wrong time.

+---------+-------------------------+-------------------------+
| id:long |     date_time:timestamp |    time_stamp:timestamp |
+---------+-------------------------+-------------------------+
|       1 | 2017-04-24 00:58:19 UTC | 2017-04-24 00:58:19 UTC |
+---------+-------------------------+-------------------------+

with options

in:
  type: mysql
  table: time_test
  host: localhost
  options: { useLegacyDatetimeCode: false }
  user: xxxx
  password: xxxx
  database: embulk_test

+---------+-------------------------+-------------------------+
| id:long |     date_time:timestamp |    time_stamp:timestamp |
+---------+-------------------------+-------------------------+
|       1 | 2017-04-24 09:58:19 UTC | 2017-04-24 09:58:19 UTC |
+---------+-------------------------+-------------------------+

Proposed change

The useLegacyDatetimeCode option set to false by default.

in:
  type: mysql
  table: time_test
  host: localhost
  user: xxxx
  password: xxxx
  database: embulk_test

+---------+-------------------------+-------------------------+
| id:long |     date_time:timestamp |    time_stamp:timestamp |
+---------+-------------------------+-------------------------+
|       1 | 2017-04-24 09:58:19 UTC | 2017-04-24 09:58:19 UTC |
+---------+-------------------------+-------------------------+

Compatibility option.

in:
  type: mysql
  table: time_test
  host: localhost
  user: xxxx
  password: xxxx
  database: embulk_test
  use_legacy_datetime_code: true

+---------+-------------------------+-------------------------+
| id:long |     date_time:timestamp |    time_stamp:timestamp |
+---------+-------------------------+-------------------------+
|       1 | 2017-04-24 00:58:19 UTC | 2017-04-24 00:58:19 UTC |
+---------+-------------------------+-------------------------+

[hito4t]

It’s about time to merge this PR.

[hito4t]

@hiroyuki-sato
I've merged the PR.
Please check.

[hiroyuki-sato]

Thanks! LGTM! 👍

[hito4t]

But embulk-input-mysql still can't fetch correct date values (#132).