Re: undefined symbol: PQcancelStart

On 20 Jun 2025, at 14:00, Laurenz Albe <laurenz.albe@cybertec.at> wrote:

On Fri, 2025-06-20 at 13:49 +0200, Peter Röthlisberger wrote:

Hello all,

Platform: Rocky Linux release 9.4 (Blue Onyx)

I try to migrate from version 16.7 to 17.5. When executing pg_upgrade —check I get the following:


could not load library "$libdir/dblink": ERROR:  could not load library "/opt/postgresql-17.5/lib/dblink.so": /opt/postgresql-17.5/lib/dblink.so: undefined symbol: PQcancelStart
In database: zen_dev1
In database: zen_prod2
could not load library "$libdir/postgres_fdw": ERROR:  could not load library "/opt/postgresql-17.5/lib/postgres_fdw.so": /opt/postgresql-17.5/lib/postgres_fdw.so: undefined symbol: PQcancelStart
In database: zen_dev1

I  tried hard to find a hint on the net. No success hence my first post here. I was able to execute the update on another server having the same OS.

How did you install "dblink.so" and "postgres_fdw.so"?
It looks like you copied them from the old installation.  That won't work.

Yours,
Laurenz Albe