Thread: BUG #17315: Postgresql needs reinstall after restore

The following bug has been logged on the website:

Bug reference:      17315
Logged by:          Markus Weyermann
Email address:      markus.weyermann@gmx.net
PostgreSQL version: 14.1
Operating system:   Linux 5.10.63-v8+ aarch64 (Bullseye)
Description:

For recovery purposes i do backup the system at filesystem level. I'm
using
a script that starts rsync to save the default Raspberry Pi OS Partitions
"/" (vfat) and "/boot" (ext4) to nfs target on a nas. Before starting the
script postgresql is shut  down by "systemctl stop postgres".
After restore, when trying to start postgres by "systemctl start postgres"
errors are logged:

"
2021-11-21 11:15:11.838 CET [842] LOG:  received fast shutdown request
2021-11-21 11:15:11.842 CET [842] LOG:  aborting any active transactions
2021-11-21 11:15:11.843 CET [2735] <user>@<server> FATAL:  terminating
connection due to administrator command
2021-11-21 11:15:11.849 CET [842] LOG:  background worker "logical
replication launcher" (PID 884) exited with exit code 1
2021-11-21 11:15:11.866 CET [879] LOG:  shutting down
2021-11-21 11:15:11.970 CET [842] LOG:  database system is shut down
/usr/lib/postgresql/14/bin/postgres: error while loading shared libraries:
libicui18n.so.63: cannot open shared object file: No such file or
directory
no data was returned by command ""/usr/lib/postgresql/14/bin/postgres" -V"
The program "postgres" is needed by pg_ctl but was not found in the
same directory as "/usr/lib/postgresql/14/bin/pg_ctl".
Check your installation.
"

When doing "apt --reinstall install postgresql-14" everything is working
again as expected.

This has been working before when running on Buster without the need of
reinstalling postgresql.

PG Bug reporting form <noreply@postgresql.org> writes:
> After restore, when trying to start postgres by "systemctl start postgres"
> errors are logged:

> /usr/lib/postgresql/14/bin/postgres: error while loading shared libraries:
> libicui18n.so.63: cannot open shared object file: No such file or
> directory

I don't see any reason to call that a Postgres bug.  Postgres certainly
did not remove that library --- even if it tried, it wouldn't have the
privileges to do so.  My guess is that you (or some administrative
process) incorrectly uninstalled that version of libicui18n some time ago,
but the existing PG server kept running because it had an open handle to
the shared library file.  After process shutdown, the kernel finished
removing the now-unreferenced library file, and then of course starting
PG up again would fail.

            regards, tom lane