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Posted to issues@drill.apache.org by "Kunal Khatua (JIRA)" <ji...@apache.org> on 2017/08/10 21:11:00 UTC
[jira] [Created] (DRILL-5715) Performance of refactored HashAgg
operator regressed
Kunal Khatua created DRILL-5715:
-----------------------------------
Summary: Performance of refactored HashAgg operator regressed
Key: DRILL-5715
URL: https://issues.apache.org/jira/browse/DRILL-5715
Project: Apache Drill
Issue Type: Bug
Components: Execution - Codegen
Affects Versions: 1.11.0
Environment: 10-node RHEL 6.4 (32 Core, 256GB RAM)
Reporter: Kunal Khatua
Assignee: Boaz Ben-Zvi
Fix For: 1.12.0
When running the following simple HashAgg-based query on a TPCH-table - Lineitem with 6Billion rows on a 10 node setup (with a single partition to disable any possible spilling to disk)
{code:sql}
select count(*)
from (
select l_quantity
, count(l_orderkey)
from lineitem
group by l_quantity
) {code}
the runtime increased from {{7.378 sec}} to {{11.323 sec}} [reported by the JDBC client].
To disable spill-to-disk in Drill-1.11.0, the {{drill-override.conf}} was modified to
{code}drill.exec.hashagg.num_partitions : 1{code}
Attached are two profiles
Drill 1.10.0 : 2675cc73-9481-16e0-7d21-5f1338611e5f.sys.drill
Drill 1.11.0 : 2675de42-3789-47b8-29e8-c5077af136db.sys.drill
A separate run was done for both scenarios with the {{planner.width.max_per_node=10}} and profiled with YourKit.
Image snippets are attached, indicating the hotspots in both builds:
Drill 1.10.0 :
Profile: 26736242-d084-6604-aac9-927e729da755.sys.drill
HotSpot: drill-1.10.0_hotspot.jpg
Drill 1.11.0 :
Profile: 26736615-9e86-dac9-ad77-b022fd791f67.sys.drill
HotSpot: drill-1.11.0_hotspot.jpg
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