Vivek Gadge <vvkgadge56(at)gmail(dot)com> writes:
> I am encountering an error after completion of PostgreSQL upgradation from
> version 13.8 to 15.6. Trying to describe a single table, I am receiving an
> error.
> psql: symbol lookup error: psql: undefined symbol: PQmblenBounded
This indicates that your psql executable is linking to an old version
of libpq.so. (Running "ldd" on the psql file should confirm that.)
You may have a problem with the library search path being used by the
dynamic loader.
regards, tom lane