[
https://issues.apache.org/jira/browse/TEZ-2217?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14381671#comment-14381671
]
Rajesh Balamohan commented on TEZ-2217:
---------------------------------------
Minor comments.
- YarnTaskSchedulerService line 648. log statement is repeated. May be it was
intented to be debug log.
- YarnTaskSchedulerService line 569. expireTime can be reused instead of
recomputing expireTimeMin.
- TestTaskScheduler Test doesn't cover the scenario when taskrequests are not
empty. It should be fine, as the patch mainly updates the expiry time for the
sessionMinHeldContainers so that they do not get released.
The issue was happening even with 20-40 second queries, but at a much lower
pace. Verified that the patch holds min containers.
> The min-held-containers constraint is not enforced during query runtime
> ------------------------------------------------------------------------
>
> Key: TEZ-2217
> URL: https://issues.apache.org/jira/browse/TEZ-2217
> Project: Apache Tez
> Issue Type: Bug
> Affects Versions: 0.6.0, 0.7.0
> Reporter: Gopal V
> Assignee: Bikas Saha
> Attachments: TEZ-2217-debug.txt.bz2, TEZ-2217.1.patch,
> TEZ-2217.2.patch, TEZ-2217.3.patch, TEZ-2217.txt.bz2
>
>
> The min-held containers constraint is respected during query idle times, but
> is not respected when a query is actually in motion.
> The AM releases unused containers during dag execution without checking for
> min-held containers.
> {code}
> 2015-03-20 15:41:53,475 INFO [DelayedContainerManager]
> rm.YarnTaskSchedulerService: Container's idle timeout expired. Releasing
> container, containerId=container_1424502260528_1348_01_000013,
> containerExpiryTime=1426891313264, idleTimeoutMin=5000
> 2015-03-20 15:41:53,475 INFO [DelayedContainerManager]
> rm.YarnTaskSchedulerService: Releasing unused container:
> container_1424502260528_1348_01_000013
> {code}
> This is actually useful only after the AM has received a soft pre-emption
> message, doing it on an idle cluster slows down one of the most common query
> patterns in BI systems.
> {code}
> create temporary table smalltable as ...;
> select ... bigtable JOIN smalltable ON ...;
> {code}
> The smaller query in the beginning throws away the pre-warmed capacity.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
