[
https://issues.apache.org/jira/browse/DRILL-2936?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14533036#comment-14533036
]
Steven Phillips commented on DRILL-2936:
----------------------------------------
I agree. I am working on it right now. My thought right now is to use when
there is a HashToMerge exchange.
Are there any other situation where we would want to use it? My other thought
was that it might be useful in the case of a sort, where there is a
HashToRandom exchange before the sort, and the ExternalSort starts spilling to
disk, this can result in very poor performance because all of the senders get
blocked as soon as any one sort fragment starts spilling. Using the spooling
buffer would prevent this from happening.
> TPCH 4 and 18 SF100 hangs when hash agg is turned off
> -----------------------------------------------------
>
> Key: DRILL-2936
> URL: https://issues.apache.org/jira/browse/DRILL-2936
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Flow
> Reporter: Ramana Inukonda Nagaraj
> Assignee: Steven Phillips
> Priority: Critical
> Fix For: 1.0.0
>
> Attachments: Screen Shot 2015-05-01 at 2.40.36 PM.png
>
>
> sys options:
> {code}
> 0: jdbc:drill:schema=dfs.drillTestDirTpch100P> alter system set
> `planner.memory.max_query_memory_per_node` = 29205777612;
> 0: jdbc:drill:schema=dfs.drillTestDirTpch100P> alter system set
> `planner.enable_hashjoin`=false;
> 0: jdbc:drill:schema=dfs.drillTestDirTpch100P> alter system set
> `planner.enable_hashagg`=false;
> {code}
> On executing TPCH 04 query hangs. From the profiles page does not look like
> any fragments are making progress, the last progress time stamps were
> sometime back.
> Attached is the logical plan.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
