Shubham Chaurasia created HIVE-25159:
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Summary: Remove support for ordered results in llap external
client library
Key: HIVE-25159
URL: https://issues.apache.org/jira/browse/HIVE-25159
Project: Hive
Issue Type: Bug
Components: Clients, Hive
Reporter: Shubham Chaurasia
Assignee: Shubham Chaurasia
Currently when querying via llap external client framework, in case of order by
queries -
1. Due to the fact that spark-llap used to wrap actual query in a subquery as
mentioned in [HIVE-19794|https://issues.apache.org/jira/browse/HIVE-19794]
a) We had to detect order by like -
{code}
orderByQuery = plan.getQueryProperties().hasOrderBy() ||
plan.getQueryProperties().hasOuterOrderBy();
{code}
Due to this we recently saw an exception like below for one of the queries that
did not have an outer order by (It was having an order by in a subquery)
{code}
org.apache.hive.service.cli.HiveSQLException: java.io.IOException:
org.apache.hadoop.hive.ql.metadata.HiveException: java.io.IOException:
java.lang.IllegalStateException: Requested to generate single split. Paths and
fileStatuses are expected to be 1. Got paths: 1 fileStatuses: 7
{code}
b) Also we had to disable following optimization -
{code}
HiveConf.setBoolVar(conf, ConfVars.HIVE_REMOVE_ORDERBY_IN_SUBQUERY, false);
{code}
2. By default we have
{{hive.llap.external.splits.order.by.force.single.split=true}} which forces us
to generate single split leading to performance bottleneck.
We should remove ordering support altogether from llap external client repo and
let clients handle it at their end.
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