I was watching the John Pattitucci video yesterday (vol 2.. the improvising/soloing one). For those who have never seen the video, there is a section where he goes over different types of chords (major, minor, dominant, diminished) in C (for simplicity) and their common alterations/extensions. In the "dominant chord" section, he talks about the C7#9#5 chord. He mentions that the scale he chooses to play over this is the "melodic minor a half step up" (Db melodic minor in this case). What gets me is WHY?? Why did he do this (he fails to explain this in the video)?