A trace file from a parallel query indicates a wait event on a write to file# 1509. But there is no datafile or tempfile with that number. What is this p1 and where is it coming from?

WAIT #1: nam='direct path write' ela= 107 p1=1509 p2=368263 p3=127

WAIT #1: nam='direct path write' ela= 109 p1=1509 p2=192517 p3=127

WAIT #1: nam='direct path write' ela= 135 p1=1509 p2=480649 p3=127

WAIT #1: nam='direct path write' ela= 110 p1=1509 p2=480776 p3=127

WAIT #1: nam='direct path write' ela= 116 p1=1509 p2=480903 p3=127

WAIT #1: nam='direct path write' ela= 123 p1=1509 p2=481030 p3=127