okumin opened a new pull request #1744: URL: https://github.com/apache/hive/pull/1744
### What changes were proposed in this pull request? Make it possible to apply `tez.shuffle-vertex-manager.min-src-fraction` and `tez.shuffle-vertex-manager.max-src-fraction` even if auto reducer parallelism is enabled. https://issues.apache.org/jira/browse/HIVE-24485 ### Why are the changes needed? With this PR, we can tweak the trade-off between timing to start and accuracy of estimation. Tez can gather more samples with higher fractions while it delays the start of the next vertex. ### Does this PR introduce _any_ user-facing change? Users who are configuring `tez.shuffle-vertex-manager.{min,max}-src-fraction` or `mapreduce.job.reduce.slowstart.completedmaps`, the alternative of `tez.shuffle-vertex-manager.min-src-fraction`, can face the change of behavior when they enable auto reducer parallelism. https://github.com/apache/tez/blob/dadc09f5a44c1cb61af00efecb3d27b92c92aa8f/tez-mapreduce/src/main/java/org/apache/tez/mapreduce/hadoop/DeprecatedKeys.java#L123 ### How was this patch tested? No test cases will be added because `Vertex#VertexManagerPluginDescriptor` is invisible from the outside of a Tez package. We can check the change by running a job and then checking the Tez log. ``` beeline -e ' SET hive.tez.auto.reducer.parallelism=true; SET hive.tez.min.partition.factor=1.0; -- enforce auto-parallelism SET tez.shuffle-vertex-manager.min-src-fraction=0.55; SET tez.shuffle-vertex-manager.max-src-fraction=0.95; CREATE TABLE mofu (name string); INSERT INTO mofu (name) VALUES ('12345'); SELECT name, count(*) FROM mofu GROUP BY name; ' ``` ``` 2020-12-04 16:10:47,170 [INFO] [Dispatcher thread {Central}] |vertexmanager.ShuffleVertexManagerBase|: Settings minFrac: 0.55 maxFrac: 0.95 auto: true desiredTaskIput: 256000000 ``` ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
