Oracle SQL Plan operation STATISTICS COLLECTOR

The STATISTICS COLLECTOR plan operation is used in conjunction with adaptive query optimization when the optimizer creates an adaptive plan.

This row source collects run-time statistics such as cardinality and data distribution (histograms).

I've encountered STATISTICS COLLECTOR as first row source of the following parent operations:

• NESTED LOOPS (ANTI, OUTER, SEMI and ordinary).
• PX SEND (HYBRID HASH)