Well the blog I know you love details and this may sound somewhat vague, I'm just at a loss as to what details to provide because I'm not sure where to go with this. Or does that suspicious cardinality 1 participate in Oracle decision to re-optimize a cursor monitored with cardinality feedback? This is logical, more recent children have the highest probability to have been optimised with the most current state of the data. Funny story tho — the table is usually empty but during the hot period, session could wait on that small delete even a few seconds.
nest...