support parse time config

[siddontang]

@shlomi-noach

I support a ParseTime config to decode timestamp and datetime to a Time structure.

[shlomi-noach]

👍

[siddontang]

@shlomi-noach

I hope this can help you in your project, but we should notice that it is a customized Time which needs to output zero time correctly for MySQL.

[siddontang]

Another way is to return origin golang Time, but for zero time, we return string "0000-00-00 00:00:00" directly.

which way do you think better?

[shlomi-noach]

Another way is to return origin golang Time, but for zero time, we return string "0000-00-00 00:00:00" directly.

That is the approach I took in https://github.com/siddontang/go-mysql/pull/86/files#diff-d9f966f86227646d11c3024f8cb537a8R651

If the date is 0, return a string. If the date is valid, return a Time.

[siddontang]

There does not handle fraction correctly.
If sec is 0 but frac is not, we should return like "0000-00-00 00:00:00.123456", of course, this is not a big problem.

So your prefer return string for zero time? @shlomi-noach

[shlomi-noach]

If sec is 0 but frac is not, we should return like "0000-00-00 00:00:00.123456", of course, this is not a big problem.

You are right. Is it possible to return 0000-00-00 00:00:00.123456 as a Time value? If so, it should be a Time.

For complete zero, I prefer a string, because it isn't actually a real Time. At least this is true for TIMESTAMP values. As for DATETIME, let me think further.

[shlomi-noach]

Hold on. 0000-00-00 00:00:00 is an invalid value and can never be a real date. (zero month? zero day? Impossible)

Which is why 0000-00-00 00:00:00.123456 is invalid as well.

So yes, 0000-00-00 00:00:00 should be a returned as a string.

The zero-Time is a valid time: https://golang.org/pkg/time/#Time.IsZero, denoting "January 1, year 1, 00:00:00 UTC.". This does not equal 0000-00-00 00:00:00.

[siddontang]

@shlomi-noach

If you create a table with a field datetime(6), you can insert "0000-00-00 00:00:00.123456", and the select result is also "0000-00-00 00:00:00.123456", not "0000-00-00 00:00:00".

Go Time can't handle both "0000-00-00 00:00:00" and "0000-00-00 00:00:00.123456", so we should return string for it, and for other valid time, we can return Time directly.

[shlomi-noach]

Go Time can't handle both "0000-00-00 00:00:00" and "0000-00-00 00:00:00.123456", so we should return string for it, and for other valid time, we can return Time directly.

This is also what I was saying :)

[siddontang]

@shlomi-noach

I have changed the return type, for zero return string, the other return golang time.

[shlomi-noach]

@siddontang if you like to wait I will update my go-mysql dependency in gh-ost and confirm this works well. This would include a very short local-tests cycle but also a several-day production tests cycle.
I will anyhow report back my findings, even if you merge.

[siddontang]

Hi @shlomi-noach

I will wait your good news :-)

[siddontang]

Hi @shlomi-noach

Any update? Can it work well in your production?

[shlomi-noach]

@siddontang I haven't deployed it yet. And it will be at least a week in testing; what i'd suggest is you can merge and I'll open an issue if there's any problems.

[siddontang]

ok, I have merged and you can use the master now. @shlomi-noach