Gbk encoding simple

[shlomi-noach]

Context: #532, see also #559

Some time after #533 was submitted by @ceshihao we found that gkb charset seems to work without specifying risky-charset argument. This PR is a stripped down version of #533 in an attempt to find the minimal set of changes where gbk is still supported.

[shlomi-noach]

Interestingly tests pass even though we use interpolateParams=true:

gh-ost/vendor/github.com/go-sql-driver/mysql/utils.go

Lines 149 to 151 in 12424e9

	if cfg.interpolateParams && unsafeCollations[cfg.collation] {
	return nil, errInvalidDSNUnsafeCollation
	}

Seems like as long as not specified via DSN, gbk is good to go.

[ceshihao]

@shlomi-noach

I think it is because gh-ost DSN only contains interpolateParams and charset, but NOT collation.

From the code you linked, the validation is on interpolateParams and collation.

[shlomi-noach]

@ceshihao makes sense. Can you possibly test this branch on your side and confirm it works as expected?

[ceshihao]

@shlomi-noach It works on my side.

BTW
I think this change is not needed either.

https://github.com/github/gh-ost/pull/560/files#diff-0ec6a3deacd5e2577724a82d8347226fR59

[shlomi-noach]

Great, thank you for testing! And thank you for your efforts.

BTW I think this change is not needed either.

Yep. I thought I might leave that as a strict reminder about interpolateParams.