Hi Uwe,

    1. Is there any equivalent to org-update-all-dblocks for the source blocks?

I think you want org-babel-execute-buffer:

Documentation
Call org-babel-execute-src-block on every source block in
the current buffer.

     2. I want to export the org file to latex, in the current setting
       the source blocks are also exported. I tried
       #+begin_src matlab  :results output raw   :eval never-export
       but it did not help.

Normally, =:results output= should be enough, but there might be some peculiarities with matlab blocks that change this behavior.
 
--Diego