Oracle Error Message
ORA-30009: Not enough memory for string operation
Reason for the Error
The memory size was not sufficient to process all the levels of the hierarchy specified by the query.
Solution
In WORKAREA_SIZE_POLICY=AUTO mode, set PGA_AGGREGATE_TARGET to a reasonably larger value. Or, in WORKAREA_SIZE_POLICY=MANUAL mode, set SORT_AREA_SIZE to a reasonably larger value.