Hi Andreas, > we have so far never added anything to check.c in pg_upgrade for a > case like this.
There is one. In 18, check_for_unicode_update() (b81ffa13e35) warns about indexes on lower(), upper(), regexp and normalize() in builtin databases when the Unicode version changes. It fires on 18 to 19 in my test. So pg_upgrade warns about a lower() index, and says nothing about a text search index in the same kind of database that misses rows for any accented word. My patch only adds more functions to that same idea. Jeff, since you wrote that check, what do you think? If the answer is release notes, I am fine with that, and I can draft the text, including the stemmer languages that changed. Thanks, Shihao
