libc to libicu via pg_dump/pg_restore?

Hi,

I have a problem which I don't understand. I have and do:

instance a, libc based, PostgreSQL 15.10:

mydb=# \l mydb
List of databases
Name | Owner | Encoding | Collate | Ctype | ICU Locale | Locale Provider | Access privileges
------+---------+----------+-------------+-------------+------------+-----------------+-------------------
mydb | my_user | UTF8 | en_US.UTF-8 | en_US.UTF-8 | | libc |

$ pg_dump -Fc -Z1 -b mydb -f mydb.dump.gz
$ ls -l mydb.dump.gz
-rw------- 1 postgres postgres 14660308577 Feb 6 08:45 mydb.dump.gz

instance b, libicu based, PostgreSQL 17.2:
$ psql postgres

# create database mydb;
# \l mydb
List of databases
Name | Owner | Encoding | Locale Provider | Collate | Ctype | Locale | ICU Rules | Access privileges
------+----------+----------+-----------------+-------------+-------------+--------+-----------+-------------------
mydb | postgres | UTF8 | icu | en_US.UTF-8 | en_US.UTF-8 | en-US | |

$ pg_restore -cC --if-exists --disable-triggers -d mydb mydb.dump.gz
pg_restore: error: could not execute query: ERROR: cannot drop the currently open database
Command was: DROP DATABASE IF EXISTS mydb;
pg_restore: error: could not execute query: ERROR: database "mydb" already exists
Command was: CREATE DATABASE mydb WITH TEMPLATE = template0 ENCODING = 'UTF8' LOCALE_PROVIDER = libc LOCALE = 'en_US.UTF-8';

pg_restore: error: could not execute query: ERROR: insert or update on table "table_1" violates foreign key constraint "..._fk"
DETAIL: Key (dokument_id)=(1000033680) is not present in table "...".
Command was: ALTER TABLE ONLY myschema.table
ADD CONSTRAINT table_fk FOREIGN KEY (dokument_id) REFERENCES myschema.dokument(id);

pg_restore: error: could not execute query: ERROR: insert or update on table "table_2" violates foreign key constraint "..._fk"
DETAIL: Key (dokument_id)=(1000033740) is not present in table "dokument".
Command was: ALTER TABLE ONLY vostra2_str.nen_dokument
ADD CONSTRAINT table_fk FOREIGN KEY (dokument_id) REFERENCES myschema.dokument(id);

I'm sorry, I sort of had to anonymize object names. But you should be able to get the gist of it. It's a dreaded message when importing. My goal is to export libc PostgreSQL 15 databases and import them into PostgreSQL 17 as libicu based databases to get away from glibc based sorting. I searched the net to find the "--disable-triggers" disable triggers when running pg_restore but the errors still occur.

What am I doing wrong or how can I better achieve that? Any help would be appreciated.

Thanks in advance.

Paul