pg_upgrade complains about not being able to find $libdir/plpython3 when upgrading a 9.4 cluster that has both python2 and python3 used. Both the 9.4 and 9.5 PGs have been built from source with python2/3 in the recommended way and the plpython3.so is present in /usr/local/pgsql/lib. I dropped the python2 database but still got the problem. The session: ------------ postgres@mayon:~$ pg_upgrade -b /usr/local/pgsql9.4/bin -B /usr/local/pgsql/bin -d /mnt/pgdata9.4 -D /mnt/pgdata Performing Consistency Checks ----------------------------- Checking cluster versions ok Checking database user is the install user ok Checking database connection settings ok Checking for prepared transactions ok Checking for reg* system OID user data types ok Checking for contrib/isn with bigint-passing mismatch ok Creating dump of global objects ok Creating dump of database schemas ok Checking for presence of required libraries fatal Your installation references loadable libraries that are missing from the new installation. You can add these libraries to the new installation, or remove the functions using them from the old installation. A list of problem libraries is in the file: loadable_libraries.txt Failure, exiting postgres@mayon:~$ cat *.txt Could not load library "$libdir/plpython3" FATAL: Python major version mismatch in session DETAIL: This session has previously used Python major version 2, and it is now attempting to use Python major version 3. HINT: Start a new session to use a different Python major version. server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general