[DRILL-5453] Managed External Sort : Sorting on a lot of columns is taking unreasonably long time

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 1.10.0
• Component/s: Execution - Relational Operators
• Assignee: Paul Rogers
• Reporter: Rahul Kumar Challapalli
• Created: 28/Apr/17 21:10
• Updated: 29/Jun/17 06:15

Description

The below query ran for ~16hrs before I cancelled it.

ALTER SESSION SET `exec.sort.disable_managed` = false;
alter session set `planner.memory.max_query_memory_per_node` = 482344960;
alter session set `planner.width.max_per_node` = 1;
alter session set `planner.width.max_per_query` = 1;
select count(*) from (select * from dfs.`/drill/testdata/resource-manager/3500cols.tbl` order by columns[450],columns[330],columns[230],columns[220],columns[110],columns[90],columns[80],columns[70],columns[40],columns[10],columns[20],columns[30],columns[40],columns[50], columns[454],columns[413],columns[940],columns[834],columns[73],columns[140],columns[104],columns[2222],columns[30],columns[2420],columns[1520], columns[1410], columns[1110],columns[1290],columns[2380],columns[705],columns[45],columns[1054],columns[2430],columns[420],columns[404],columns[3350], columns[3333],columns[153],columns[356],columns[84],columns[745],columns[1450],columns[103],columns[2065],columns[343],columns[3420],columns[530], columns[3210] ) d where d.col433 = 'sjka skjf';
alter session set `planner.memory.max_query_memory_per_node` = 2147483648;

The data set and the logs are too large to attach to a jira. But below is a description of the data

No of records : 1,000,000
No of columns : 3500
Length of each column : < 50

The profile is attached and I will give my analysis on why I think its an un-reasonable amount of time soon.

Issue Links

• Is contained by: DRILL-5211 Queries fail due to direct memory fragmentation