hqx created CALCITE-4522:
----------------------------
Summary: optimize sort cost formula
Key: CALCITE-4522
URL: https://issues.apache.org/jira/browse/CALCITE-4522
Project: Calcite
Issue Type: Improvement
Components: core
Reporter: hqx
The old method to compute the cost of sort has some problem.
# when there is no need to sort, it still to compute the cpu cost of sort.
# use n * log(n) rowBytes to estimate the cpu cost may be inaccurate, where n
means the output row count of the sort operator, and rowBytes means the average
bytes of one row .
Instead, I give follow suggestion.
# the cpu cost is zero if there is no need to sort.
# use m * log(n) rowBytes to compute the cpu cost, where m is the sum of
offset + limit and n means input row count.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
