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From "Enis Soztutar (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-9905) Enable using seqId as timestamp
Date Tue, 15 Apr 2014 02:07:18 GMT

    [ https://issues.apache.org/jira/browse/HBASE-9905?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13969140#comment-13969140
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Enis Soztutar commented on HBASE-9905:
--------------------------------------

Thanks Billie. This issue proposes a similar thing. Our seqId is a monotonically increasing
number, and all edits in WAL are ordered by this, so if a table is predeclared to use this,
the correctness in terms of ordering is guaranteed, plus a lot of optimizations are possible
on the read side (HBASE-10247) 

> Enable using seqId as timestamp 
> --------------------------------
>
>                 Key: HBASE-9905
>                 URL: https://issues.apache.org/jira/browse/HBASE-9905
>             Project: HBase
>          Issue Type: New Feature
>            Reporter: Enis Soztutar
>
> This has been discussed previously, and Lars H. was mentioning an idea from the client
to declare whether timestamps are used or not explicitly. 
> The problem is that, for data models not using timestamps, we are still relying on clocks
to order the updates. Clock skew, same milisecond puts after deletes, etc can cause unexpected
behavior and data not being visible.  
> We should have a table descriptor / family property, which would declare that the data
model does not use timestamps. Then we can populate this dimension with the seqId, so that
global ordering of edits are not effected by wall clock. 
> For example, META will use this. 
> Once we have something like this, we can think of making it default for new tables, so
that the unknowing user will not shoot herself in the foot. 



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