Re: Changing collate & ctype for an existing database

On 07/12/2017 09:31 PM, Tom Lane wrote:
> rihad <rihad(at)mail(dot)ru> writes:
>> On 07/12/2017 01:54 PM, Albe Laurenz wrote:
>>> As you see, your index is still sorted according to the C collation
>>> and scanning it returns wrong results.
>> This ordering issue can certainly be classified as an inconsistency, but
>> nothing to lose sleep over. Is this all that is normally meant when
>> saying "index corruption"?
> Laurenz neglected to point out that if the index isn't sorted the way that
> the system assumes it is, then searches may fail to find values that are
> present (due to descending into the wrong subtree), and by the same token
> insertions may fail to enforce uniqueness. That's pretty corrupt in
> my book.
>
> regards, tom lane
>
What if only English letters are used in the textual indices (ascii
0-127), would they still be impacted after datctype&datcollate
"C"->"en_US.UTF-8" change? Encoding has always been UTF8, btw.

postgres=# \l
List of databases
Name | Owner | Encoding | Collate | Ctype | Access
privileges
-----------+----------+----------+-------------+-------------+-----------------------
mydb | myuser | UTF8 | C | C |