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evanelias | 15 days ago
There wasn't a clear winner in utf-8 at the time, especially given its 6-byte-max representation back then. Memory and storage were a lot more limited.
And yes while 6 bytes was the maximum, a bunch of critical paths (e.g. sorting logic) in old MySQL required allocating a worst-case buffer size, so this would have been prohibitively expensive.
booi|3 days ago
Even if there were no codepoints in the 4-byte range yet, they could and should have implemented it anyway. It literally does not take any more storage because it is a variable width encoding.
evanelias|2 days ago
No, it was 1 to 6 bytes until RFC 3629 (Nov 2003). AFAIK development of MySQL 4.1 began prior to that, despite the release not happening until afterwards.
Again, they absolutely should have addressed it sooner. But people make mistakes, especially as we're talking about a venture-funded startup in the years right after the dot-com crash.
> It literally does not take any more storage because it is a variable width encoding.
I already addressed that in my previous comment: in old versions of MySQL, a number of critical code paths required allocating worst-case buffer sizes, or accounting for worst-case value lengths in indexes, etc. So if a charset allows 6 bytes per character, that means multiplying max length by 6, in order to handle the pathological case.