> One coincidence is that we started seeing the first symptoms of this > around the same time as libicu was updated with a security patch. > However, postgres hasn’t been restarted and doesn’t reference the > new version in its process maps. Plus state groups are integers > anyway. We also use the C locale, not ICU. Sounds as if you are hit by locale changes: https://wiki.postgresql.org/wiki/Locale_data_changes I think you will need to upgrade to prevent future problems like that: Postgres 15 introduced some mechanisms to track and validate version discrepancies after an OS update. Postgres 17 added a "built-in" collation provider which is independent of glibc
