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Posted to issues@kylin.apache.org by "RenZhiMin (JIRA)" <ji...@apache.org> on 2018/04/19 10:12:00 UTC

[jira] [Comment Edited] (KYLIN-3341) SQL queries take up too much memory

    [ https://issues.apache.org/jira/browse/KYLIN-3341?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16443819#comment-16443819 ] 

RenZhiMin edited comment on KYLIN-3341 at 4/19/18 10:11 AM:
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The query has 12 segments. When 14:34:27 SQL execution, and initialize the first segment, in 14:34:28, 686 when initializing the second segment, in 14:34:30, 104 when initializing the third segment, in 14:34:31, 434 when initializing the fourth segment, and then in 14:35:03 began to have a large number of request data back hbase, when 14:36:01 out of memory


was (Author: renzm):
The query has 12 segments. When 14:34:27 SQL execution, and initialize the first segment, in 14:34:28, 686 when initializing the second segment, in 14:34:30, 104 when initializing the third segment, in 14:34:31, 434 when initializing the fourth segment, and then in 14:35:03 began to have a large number of hbase request of return data, alarm when 14:36:01 memory

> SQL queries take up too much memory
> -----------------------------------
>
>                 Key: KYLIN-3341
>                 URL: https://issues.apache.org/jira/browse/KYLIN-3341
>             Project: Kylin
>          Issue Type: Improvement
>          Components: Storage - HBase
>    Affects Versions: v2.0.0
>            Reporter: RenZhiMin
>            Priority: Major
>         Attachments: log.txt
>
>
> Some SQL will take up too much memory in the application, the service is not stable, after analysis because the SQL query need to scan the relevant segemnt corresponding hbase table, is through the thread asynchronous request related to SQL cuboid corresponding region. After each segment makes a request, wait for the data to process the hbase callbacks.
> But sometimes SQL involves more segments, and before all the segments make requests, there is a large amount of data returned, leading to memory alarm and service instability.



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