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From "Jerry He (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-15572) Adding optional timestamp semantics to HBase-Spark
Date Wed, 13 Apr 2016 16:51:25 GMT

    [ https://issues.apache.org/jira/browse/HBASE-15572?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15239584#comment-15239584
] 

Jerry He commented on HBASE-15572:
----------------------------------

bq. For example, (select col1 from hbaseTable where rowkey = 1 and TIMESTAMP > 123345)
bq. However, it may cause potential troubles. For example, if a virtual column is put into
the sql schema, users may have select timestamp from table. It is a valid query in sql, but
not valid in Hbase, since this timestamp is implicit in Hbase attached to a row, there is
really no such column in the Hbase row. We cannot construct a scan using this. Thus it is
an invalid query for HBase.

Selecting the timestamp from table (have it in projection) is tricky, but it could still be
valid for advanced use case.  Having it in predicates should anyway work.
This support is for SQL. Shouldn't we leverage more of the flexibility of SQL?
But it is probably for another discussion.

The patch looks good.


> Adding optional timestamp semantics to HBase-Spark
> --------------------------------------------------
>
>                 Key: HBASE-15572
>                 URL: https://issues.apache.org/jira/browse/HBASE-15572
>             Project: HBase
>          Issue Type: New Feature
>          Components: spark
>            Reporter: Weiqing Yang
>            Assignee: Weiqing Yang
>             Fix For: 2.0.0
>
>         Attachments: HBASE-15572-1.patch, HBASE-15572-10.patch, HBASE-15572-2.patch,
HBASE-15572-3.patch, HBASE-15572-4.patch, HBASE-15572-5.patch, HBASE-15572-6.patch, HBASE-15572-7.patch,
HBASE-15572-8.patch, HBASE-15572-9.patch
>
>
> Right now the timestamp is always latest. With this patch, users can select timestamps
they want.
> In this patch, 4 parameters, "timestamp", "minTimestamp", "maxiTimestamp" and "maxVersions"
are added to HBaseSparkConf. Users can select a timestamp, they can also select a time range
with minimum timestamp and maximum timestamp. A new test for selecting records with different
timestamps is added.



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