Oracle to PostgreSQL Migration - Need Information

Hello,

I have a customer that is about to undertake a migration of an Oracle 11g
database to PostgreSQL 9.x (exact version to be determined). I am talking
not only of the migration of schemas and data, but also of a substantial
codebase of Pl/SQL stored procedures, as well as many triggers.

I don't think they know yet what they are up against. Everything I have
read is that this is a very substantial effort. At this stage, they would
be particularly interested in realistic and practical information on how to
estimate the effort required as well as any best-practices or guidance on
transition strategies.

I have found official documentation on the PostgreSQL site for porting
Pl/SQL to PL/pgSQL. This is excellent technical documentation. However,
there success will require that they are well prepared realistically
understanding the scope of the effor they are asbout to undertake.

Thanks for any response!