Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Petr Jelinek wrote:
>>> I'm not sure how well it will work to replace all the bits of LIKE and
>>> regular expressions with ICU API calls. One problem is that ICU likes
>>> to do case folding as a whole string, not by character. I need to do
>>> more research about that.
>> Can't we use the regular expression api provided by ICU, or is that too
>> incompatible?
> That probably won't fly very well -- it would be rather absurd to have
> different regex behavior when ICU is compiled compared to when it's
> not. Perhaps down the road we could have an extension that provides
> ICU-based regex operators, but most likely not in core.
The regex stuff does not handle case-insensitivity by case-folding the
data string, anyway. Rather, it does that by converting 'a' or 'A'
in the pattern to the equivalent of '[aA]'. So performance for that
step is not terribly critical.
regards, tom lane