[jira] [Created] (DRILL-3482) LIMIT not terminating early enough when concurrent queries are running

["Aman Sinha (JIRA)" <ji...@apache.org>]

Aman Sinha created DRILL-3482:
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             Summary: LIMIT not terminating early enough when concurrent queries are running
                 Key: DRILL-3482
                 URL: https://issues.apache.org/jira/browse/DRILL-3482
             Project: Apache Drill
          Issue Type: Bug
          Components: Execution - Flow
    Affects Versions: 1.1.0
            Reporter: Aman Sinha
            Assignee: Chris Westin


This behavior was observed on a 30 node cluster, width.max_per_node = 23.  Run a long-running CTAS query that does joins, aggregations and takes about 5 minutes.  While this query is running, submit the following type of query: 
{code}
SELECT * FROM table LIMIT 10;
{code}
The table consists of parquet files and the size of this table is of the order of few hundred GB.

The elapsed time of this query was seen to be more than 2 minutes.   There were 690 minor fragments doing the Scan and the majority of them finished in a few seconds while a small number took 2 mins.   

When the same query was run on an idle system, the query took about 6 seconds to complete.  It appears that when concurrent queries are running, the early termination for Limit is not getting processed fast enough on all the minor fragments. 



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