[jira] [Commented] (HBASE-15324) Jitter may cause desiredMaxFileSize overflow in ConstantSizeRegionSplitPolicy and trigger unexpected split

["Esteban Gutierrez (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-15324?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15649100#comment-15649100 ] 

Esteban Gutierrez commented on HBASE-15324:
-------------------------------------------

We ran into this in 1.2 with a customer and that caused 10s of thousands of new regions to be created in matter of hours. I'm going to push it from 0.98 to 1.2

> Jitter may cause desiredMaxFileSize overflow in ConstantSizeRegionSplitPolicy and trigger unexpected split
> ----------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-15324
>                 URL: https://issues.apache.org/jira/browse/HBASE-15324
>             Project: HBase
>          Issue Type: Bug
>    Affects Versions: 2.0.0, 1.1.3
>            Reporter: Yu Li
>            Assignee: Yu Li
>             Fix For: 2.0.0, 1.3.0, 1.4.0
>
>         Attachments: HBASE-15324.patch, HBASE-15324_v2.patch, HBASE-15324_v3.patch, HBASE-15324_v3.patch
>
>
> We introduce jitter for region split decision in HBASE-13412, but the following line in {{ConstantSizeRegionSplitPolicy}} may cause long value overflow if MAX_FILESIZE is specified to Long.MAX_VALUE:
> {code}
> this.desiredMaxFileSize += (long)(desiredMaxFileSize * (RANDOM.nextFloat() - 0.5D) * jitter);
> {code}
> In our case we specify MAX_FILESIZE to Long.MAX_VALUE to prevent target region to split.



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