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https://issues.apache.org/jira/browse/TAJO-1397?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14628130#comment-14628130
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ASF GitHub Bot commented on TAJO-1397:
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Github user jihoonson commented on the pull request:
https://github.com/apache/tajo/pull/608#issuecomment-121633024
@jinossy, really nice work!
I'm still reviewing and not finished yet. Here, I left some comments first,
and will finish soon.
* StringUtils.java
* The comment of isPureAscii() is incomplete.
* QueryCoordinatorProtocol.proto
* As you know, @hyunsik is working on refactoring our error propagation
system. According to the guide at
https://cwiki.apache.org/confluence/display/TAJO/RPC+Protocol+Design+Guide,
please separate QueryCoordinatorProtocolService from this file.
* Also, please add some comments for the methods of
QueryCoordinatorProtocolService.
* QueryInProgress.java
* Please change the comments of allocateToQueryMaster() into the formal
java doc format.
* Please add some comments for submitToQueryMaster().
* QueryManager.java
* The name of startQueryJob() looks not intuitive. How about
isQueryExecutable()?
* TajoResourceManager.java
* Please remove the unused parameter, ```systemConf```, from the
constructor.
* QuerySchedulingInfo.java
* Please add some comments for the class and its variables.
* SimpleScheduler.java
* Please add some comments for the class.
* Would you please explain what PARALLEL_QUERY_LIMIT means?
> Resource allocation should be fine grained.
> -------------------------------------------
>
> Key: TAJO-1397
> URL: https://issues.apache.org/jira/browse/TAJO-1397
> Project: Tajo
> Issue Type: Improvement
> Components: QueryMaster, resource manager, Worker
> Reporter: Hyunsik Choi
> Assignee: Jinho Kim
> Fix For: 0.11.0
>
> Attachments: ResoruceSequence.jpg, TAJO-1397.patch,
> old_resource_circuit.png, resource_circuit.png
>
>
> See the comment:
> https://issues.apache.org/jira/browse/TAJO-540?focusedCommentId=14359478&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14359478
> From the discussion in TAJO-540
> {quote}
> In general, query (or job) scheduler aims at the maximum resource
> utilization. For multi-tenancy, we also need to consider the fairness for
> multiple users (or queries). BTW, the maximum resource utilization and
> fairness are usually conflict to each other in many cases. To mitigate this
> problem, many scheduler seems to use preemption approach.
> In this point, our resource and scheduler system has the following problems:
> * A query exclusively uses allocated resources at the first time until the
> query is completed or failed.
> * There is no mechanism to deallocate resources during query processing.
> * Preempt is also not allowed.
> To achieve the multi tenancy, we should change our resource circulation.
> Especially, resource allocation must be fine grained instead of per query.
> So, I'll create a jira issue to change the resource circulation. We have to
> do this issue firstly in my opinion. If we achieve this, implementing
> multi-tenant scheduler would be much easier than now. It would be a good
> starting point of this issue.
> {quote}
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