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https://issues.apache.org/jira/browse/HBASE-18824?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Xiang Li updated HBASE-18824:
-----------------------------
    Attachment: HBASE-18824.master.002.patch

> Add meaningful comment to HConstants.LATEST_TIMESTAMP to explain why it is 
> MAX_VALUE
> ------------------------------------------------------------------------------------
>
>                 Key: HBASE-18824
>                 URL: https://issues.apache.org/jira/browse/HBASE-18824
>             Project: HBase
>          Issue Type: Improvement
>            Reporter: Xiang Li
>            Assignee: Xiang Li
>            Priority: Minor
>         Attachments: HBASE-18824.master.000.patch, 
> HBASE-18824.master.001.patch, HBASE-18824.master.002.patch
>
>
> Thanks to [Jerry and Chia-Ping Tsai's 
> comments|https://issues.apache.org/jira/browse/HBASE-18824?focusedCommentId=16167392&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-16167392]
>  to correct my wrong understanding. 
> The following documentation says that by default(when the timestamp is not 
> specified for Put or Delete), system uses the server's {{currentTimeMillis}}.
> 1. In chapter 27.2.4 Put 
> bq. Doing a put always creates a new version of a cell, at a certain 
> timestamp. {color:#205081}By default the system uses the server’s 
> currentTimeMillis{color}, ...
> 2. In chapter 27.2.5 Delete
> bq. Deletes work by creating tombstone markers. For example, let’s suppose we 
> want to delete a row. For this you can specify a version, or else 
> {color:#205081}by default the currentTimeMillis is used.{color}...
> It seems not consistent with the code. Because in the client side's code, 
> when timestamp is not specified, HConstants.LATEST_TIMESTAMP is used, which 
> is Long.MAX_VALUE, rather than {{System.currentTimeMillis()}}.
> However, the documentation is correct, because on the server side,  timestamp 
> of Put cell with HConstants.LATEST_TIMESTAMP will be replaced with server's 
> {{currentTimeMillis}}.
> So we decide to add more comments to HConstants.LATEST_TIMESTAMP to help the 
> new comers steer clear of the confusion.



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