Re: undefined symbol: PQcancelStart

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
anotherserver 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