sort_area_size and hash_area_size

Hi All,
  I did some testing on this quite some time ago and was hoping to have a refresher.... I have an application with a particularly nasty view... given that I can not go in and fix the view without breaching protocol, I was going to increase the sort area size and hash area size at the session level.... Now that I'm revisiting this I remember there were some considerations for negatively impacting performance. After failing to find any information on this negative impact... does anyone know of some considerations I should make before going forward?

Thank you,

     Oliver

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