We have just discovered a bug in our system which made a wrong calculation.
Fortunately for us, all documents contain enough data to reprocess the calculation.
How can I run an "update" so that it recomputes a field, based on the content of other fields ?
"total_price": 30.2 (wrong value, based on erroneous calculations)
I would like to replace the "total_price" by the result of "amount" * "unit_price" in all documents (~500000000)
Many thanks for your help