Padma Penumarthy created DRILL-6071:
---------------------------------------
Summary: Limit batch size for flatten operator
Key: DRILL-6071
URL: https://issues.apache.org/jira/browse/DRILL-6071
Project: Apache Drill
Issue Type: Bug
Components: Execution - Flow
Affects Versions: 1.12.0
Reporter: Padma Penumarthy
Assignee: Padma Penumarthy
Fix For: 1.13.0
flatten currently uses an adaptive algorithm to control the outgoing batch
size.
While processing the input batch, it adjusts the number of records in outgoing
batch based on memory usage so far. Once memory usage exceeds the configured
limit, the algorithm becomes more proactive and adjusts the limit half way
through and end of every batch. All this periodic checking of memory usage is
unnecessary overhead and impacts performance. Also, we will know only after the
fact.
Instead, figure out how many rows should be there in the outgoing batch from
incoming batch.
The way to do that would be to figure out average row size of the outgoing
batch and based on that figure out how many rows can be there for a given
amount of memory. value vectors provide us the necessary information to be able
to figure this out.
--
This message was sent by Atlassian JIRA
(v6.4.14#64029)
