[ https://issues.apache.org/jira/browse/PIG-4148?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Daniel Dai updated PIG-4148: ---------------------------- Issue Type: Bug (was: Sub-task) Parent: (was: PIG-3446) > Tez order-by is often skewed because FindQuantiles UDF is called with small > number > ---------------------------------------------------------------------------------- > > Key: PIG-4148 > URL: https://issues.apache.org/jira/browse/PIG-4148 > Project: Pig > Issue Type: Bug > Components: tez > Reporter: Cheolsoo Park > Fix For: 0.14.1 > > Attachments: generate_sample.py, metric_retention.explain, > popackage.log, samples_logs.tar.gz > > > In Tez, FindQuantiles UDF is called with a smaller number of samples than MR > resulting in skew in range partitions. > For example, I have a job that runs sampling with a parallelism of 300. Since > each task samples 100 records, the total sample should be 30K. But > FindQuantiles UDF is called with only 300 samples. -- This message was sent by Atlassian JIRA (v6.3.4#6332)