*: fix wrong timezone when env TZ is not set

[zier-one]

What problem does this PR solve?

If the environment TZ is not set , the value of time.Local.String() is Local,
when we try to connect to mysql using Local timezone, we will get an error: Error 1298: Unknown or incorrect time zone: 'Local'

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test

Release note

• Fix using incorrect timezone when env TZ is not set

[amyangfei]

I found in some environment without TZ env, using timezone="Local" can be success, sounds strange.

[2020/04/28 16:22:00.429 +08:00] [INFO] [mysql.go:341] ["Start mysql sink"] [dsn="root@tcp(127.0.0.1:3306)/?interpolateParams=true&loc=Local&multiStatements=true&time_zone=%22Local%22"]

[amyangfei]

BTW, is the loc variable needed in DSN, as we don't provide parseTime=true

[zier-one]

I found in some environment without TZ env, using timezone="Local" can be success, sounds strange.

[2020/04/28 16:22:00.429 +08:00] [INFO] [mysql.go:341] ["Start mysql sink"] [dsn="root@tcp(127.0.0.1:3306)/?interpolateParams=true&loc=Local&multiStatements=true&time_zone=%22Local%22"]

Is the downstream TiDB?

Error 1298: Unknown or incorrect time zone: 'Local' this error is reported by MySQL57

[amyangfei]

I found in some environment without TZ env, using timezone="Local" can be success, sounds strange.

[2020/04/28 16:22:00.429 +08:00] [INFO] [mysql.go:341] ["Start mysql sink"] [dsn="root@tcp(127.0.0.1:3306)/?interpolateParams=true&loc=Local&multiStatements=true&time_zone=%22Local%22"]

Is the downstream TiDB?

Error 1298: Unknown or incorrect time zone: 'Local' this error is reported by MySQL57

Yes, TiDB works well and MySQL raises the error.

[amyangfei]

LGTM

[amyangfei]

/run-all-tests