Cissy Houston is not happy over the invite she received from longtime Whitney Houston mentor Clive Davis. The industry legend invited the Houston matriarch and her family to his annual pre-Grammy party ... which, one year ago, was when (but not where) Whitney perished.

Cissy spoke to Access Hollywood (via Us Weekly), and mama was not happy.

"I got an invitation to the party, which is the most obscene thing," she snapped. "I don't know why they would want me to come to the party in which she died, you know? Unheard of."

In fairness to Davis, it probably would have been equally effed up if he didn't acknowledge Cissy -- after all, her daughter made Davis a household name, and arguably vice versa. "I guess maybe he just sent me a copy [of the invite] for remembrance sake," she muttered. Maybe she can send him a copy of her book for the same purpose.

As for the rest of Houston's family, Whitney's daughter Bobbi Kristina wasn't mentioned. However, her brother Gary and her opportunist sister-in-law Pat (star of the reality show 'The Houstons: On Our Own') plan on attending.

"[Clive] was such an important part of Whitney's life. I mean, that was her industry father and he really, really was," Pat said. "My husband and I will definitely be there this weekend to support Clive. Absolutely."

And, you know, to promote your show. Because even though Whitney's dead, they need to keep the dream (and the meal ticket) alive.