pgsql-bugs@postgresql.org writes:
> I send a query with bad function.
> The server answer me an error with text : ERROR: Function 'octet_length(unknown)' does not exist
> Unable to identify a function that satisfies the given argument types
> You may need to add explicit typecasts.
> Then, i call PQclear to free result context, the core is dump with memory fault.
Are you sure this isn't your own bug --- like calling PQclear twice on
the same PGresult in your error-recovery code path?
regards, tom lane