Data Mart with PostgreSQL (Please!)

> Hello,
>
> My objective is design and build a Data Mart what enable OLAP queries
> using Open Source tools.
>
> I will want know if the solution below is possible and correct or exist a
> better solution:
>
> 1 - The data will be generate to PostgreSQL from a commercial Database by
> a ETL process.
>
> 2 - The Mondrian will be used as the OLAP server.
>
> 3 - The JPivot will be used for OLAP navigations and queries.
>
> I need know opinions about this approach. I'm don't very experienced in
> this issue.
>
> I thank in advance any suggestions, criticisms and opinions.
>
> Regards,
>
> Renato Cramer.