pg_upgrade Error- Kindly help - Mailing list pgsql-novice

Hello,

  I am trying to do a pg_upgrade from V16 to V18.

We are running RHEL 9.8.

All our postgresql binary files are in /bin directory. There is no separate /bin/postgre/v16/bin directory.

Our Sysadmin did his magic and now we have the new bin files in the same /bin directory.  ( In effect we do not have a old-binary and new-binary directory ).

To make a long story short,

1.I created a new local directory called /binary_files/V16 and copied the bin files from a non upgraded server to this server, just to have a copy of the old binaries.

2.  Moved my instance data directory from data to data_old

3. Did an initdb with the new V18 pg_ctl to create a new empty Instance.

When I do a dry run of pg_upgrade I get the below error .

1. What should I do to overcome this error?
2. Why is it looking for port number 50432 ? We never used this port before.

Regards

Ram

-----------------------------------------------------------------

  pg_upgrade run on Tue Jul 21 10:41:10 2026

-----------------------------------------------------------------

command: "/var/lib/pgsql/binary_files/V16/pg_ctl" -w -l "/var/lib/pgsql/AUFGABEN-VERWAL/data/pg_upgrade_output.d/20260721T104110.789/log/pg_upgrade_server.log" -D "/var/lib/pgsql/AUFGABEN-VERWAL/data_old" -o "-p 50432 -b  -c listen_addresses='' -c unix_socket_permissions=0700 -c unix_socket_directories='/var/lib/pgsql/work/scripts'" start >> "/var/lib/pgsql/AUFGABEN-VERWAL/data/pg_upgrade_output.d/20260721T104110.789/log/pg_upgrade_server.log" 2>&1

waiting for server to start....2026-07-21 10:41:10.902 CEST [44817] FATAL:  incompatible library "/usr/lib64/pgsql/pg_stat_statements.so": version mismatch

2026-07-21 10:41:10.902 CEST [44817] DETAIL:  Server is version 16, library is version 18.

2026-07-21 10:41:10.902 CEST [44817] LOG:  database system is shut down

stopped waiting

pg_ctl: could not start server

Examine the log output.