Re: pg_upgrading to 10.1 corrupts (varchar,varchar) UNIQUE indices

On 12/22/2017 05:09 PM, Laurenz Albe wrote:
> rihad wrote:
>> Hi there, this is a reproducible error. We recently pg_upgraded our
>> production database to 10.1 from 9.6.6. The upgrade runs fine with the
>> suggestion to analyze all data.
> [...]
>
>> Trying to find data using the specified indices fails to find matching rows:
> [...]
>
>> reindexing the table fixes the issue:
> Did you also upgrade the operating system or at least libc?
It looks like it.

$ ll /lib/libc.so.7
-r--r--r--  1 root  wheel  1647104 Jun 19  2017 /lib/libc.so.7

this never was a major/minor OS upgrade, just whatever FreeBSD patch 
releases included.

>
> Then the problem could come from a modified collation.
> Compare https://www.postgresql.org/message-id/CB4D1C6BAA80CF146CB0D4F2%40eje.credativ.lan

de (German) was just an example, the inability to find matching rows 
affected other languages like fr or even en, too.
It does look like a collation issue, though.