Khurram Faraaz created DRILL-3648:
-------------------------------------
Summary: NTILE function returns incorrect results
Key: DRILL-3648
URL: https://issues.apache.org/jira/browse/DRILL-3648
Project: Apache Drill
Issue Type: Bug
Components: Execution - Flow
Affects Versions: 1.2.0
Environment: private-branch
https://github.com/adeneche/incubator-drill/tree/new-window-funcs
Reporter: Khurram Faraaz
Assignee: Chris Westin
NTILE function returns incorrect results for larger dataset. I am working on
reproducing the problem with a smaller dataset.
The inner query that uses NTILE should have divided the rows into two sets
(tiles) where each tile consists of (937088 + 1 ) rows , 937088 rows
{code}
0: jdbc:drill:schema=dfs.tmp> select ntile_key2, count(ntile_key2) from (select
ntile(2) over(partition by key2 order by key1) ntile_key2 from `twoKeyJsn.json`
where key2 = 'm') group by ntile_key2;
+-------------+----------+
| ntile_key2 | EXPR$1 |
+-------------+----------+
| 1 | 1 |
| 2 | 1874176 |
+-------------+----------+
2 rows selected (49.406 seconds)
{code}
Explain plan for inner query that returns wrong results.
{code}
0: jdbc:drill:schema=dfs.tmp> explain plan for select ntile(2) over(partition
by key2 order by key1) from `twoKeyJsn.json` where key2 = 'm';
+------+------+
| text | json |
+------+------+
| 00-00 Screen
00-01 UnionExchange
01-01 Project(EXPR$0=[$0])
01-02 Project($0=[$2])
01-03 Window(window#0=[window(partition {0} order by [1] range
between UNBOUNDED PRECEDING and CURRENT ROW aggs [NTILE($2)])])
01-04 SelectionVectorRemover
01-05 Sort(sort0=[$0], sort1=[$1], dir0=[ASC], dir1=[ASC])
01-06 Project(key2=[$0], key1=[$1])
01-07 HashToRandomExchange(dist0=[[$0]])
02-01 UnorderedMuxExchange
03-01 Project(key2=[$0], key1=[$1],
E_X_P_R_H_A_S_H_F_I_E_L_D=[castInt(hash64AsDouble($0))])
03-02 SelectionVectorRemover
03-03 Filter(condition=[=($0, 'm')])
03-04 Scan(groupscan=[EasyGroupScan
[selectionRoot=maprfs:/tmp/twoKeyJsn.json, numFiles=1, columns=[`key2`,
`key1`], files=[maprfs:///tmp/twoKeyJsn.json]]])
{code}
Total number of rows in partition that has key2 = 'm'
{code}
0: jdbc:drill:schema=dfs.tmp> select count(key1) from `twoKeyJsn.json` where
key2 = 'm';
+----------+
| EXPR$0 |
+----------+
| 1874177 |
+----------+
1 row selected (37.581 seconds)
{code}
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
