os upgrade 18 to 20

gistfile1.txt

https://jumpcloud.com/blog/how-to-upgrade-ubuntu-20-04-to-ubuntu-22-04
https://askubuntu.com/questions/1098480/attempting-to-upgrade-from-ubuntu-server-16-04-to-18
https://gitlab.com/gitlab-com/gl-infra/production-engineering/-/issues/13273
https://aws.amazon.com/blogs/database/manage-collation-changes-in-postgresql-on-amazon-aurora-and-amazon-rds/

https://www.youtube.com/watch?v=0E6O-V8Jato
Sorting Out glibc Collation Challenges: Joe Conway - PGCon 2023


glibc upgrades from 2.27 to 2.31, which changes the ordering

glibc
2.27 > 2.31 
index corruption

postgres=# SELECT pg_encoding_to_char(encoding),*
FROM pg_database WHERE datname = current_database();
-[ RECORD 1 ]-------+------------
pg_encoding_to_char | UTF8
datname             | postgres
datdba              | 10
encoding            | 6
datcollate          | en_US.UTF-8
datctype            | en_US.UTF-8
datistemplate       | f
datallowconn        | t
datconnlimit        | -1
datlastsysoid       | 13017
datfrozenxid        | 548
datminmxid          | 1
dattablespace       | 1663
datacl              |

postgres=# \q
postgres@ubuntu:~$ psql
psql (12.22 (Ubuntu 12.22-0ubuntu0.20.04.1), server 10.23 (Ubuntu 10.23-0ubuntu0.18.04.2))
Type "help" for help.

postgres=# select bt_index_check('testcoll_pkey'::regclass);
ERROR:  item order invariant violated for index "testcoll_pkey"
DETAIL:  Lower index tid=(1,1) (points to heap tid=(0,2)) higher index tid=(1,2) (points to heap tid=(0,1)) page lsn=0/16588A0.
postgres=#