Re: case insensitive collation of Greek's sigma

Jakub Jedelsky <jakub.jedelsky@gooddata.com> writes:
> during our tests of Postgres with ICU we found an issue with ILIKE of upper
> and lowercase sigma (Σ). The letter has two lowercase variants σ and ς (at
> the end of a word). I'm working with en_US and en-US-x-icu collations and
> results are a bit unexpected - they are inverted:

Not sure why you would expect en_US collation to give appropriate results
for Greek?  I think you'd need el_GR.

Be that as it may, Postgres doesn't define anything about this --- we
just rely on the collations supplied by the respective system libraries
(libc or ICU).  You'd need to file bugs against those libraries if you
think their behavior should change.

            regards, tom lane