This is just a short note that Oracle has added several nice details to 184.108.40.206 and 220.127.116.11 respectively that can be helpful for troubleshooting.
ASH, PGA Memory And TEMP Consumption
Since 18.104.22.168 the V$ACTIVE_SESSION_HISTORY view (that requires Enterprise Edition plus Diagnostic License) contains the PGA_ALLOCATED and TEMP_SPACE_ALLOCATED columns.
In particular the latter closes an instrumentation gap that always bothered me in the past: So far it wasn't easy to answer the question which session used to allocate TEMP space in the past. Of course it is easy to answer while the TEMP allocation was still held by a session by looking at the corresponding V$ views like V$SORT_USAGE, but once the allocation was released answering questions like why was my TEMP space exhausted three hours ago was something that couldn't be told by looking at the information provided by Oracle.