[jira] [Commented] (YARN-4178) [storage implementation] app id as string can cause incorrect ordering

["Varun Saxena (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/YARN-4178?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14804414#comment-14804414 ] 

Varun Saxena commented on YARN-4178:
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ApplicationId is basically a combination of cluster timestamp and a monotonically increasing sequence number/id. 
We can hence store application id as a sequence of 2 longs or 2 ints in the row key to ensure order is maintained.

We can encode it on the way in and decode it as a string on the way out by using ApplicationId#toString.

We are however storing app attempts ids and container ids in the same way. They will go into the entity table.



> [storage implementation] app id as string can cause incorrect ordering
> ----------------------------------------------------------------------
>
>                 Key: YARN-4178
>                 URL: https://issues.apache.org/jira/browse/YARN-4178
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: timelineserver
>    Affects Versions: YARN-2928
>            Reporter: Sangjin Lee
>            Assignee: Varun Saxena
>
> Currently the app id is used in various places as part of row keys and in column names. However, they are treated as strings for the most part. This will cause a problem with ordering when the id portion of the app id rolls over to the next digit.
> For example, "app_1234567890_100" will be considered *earlier* than "app_1234567890_99". We should correct this.



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