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From "Dave Latham (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-14355) Scan different TimeRange for each column family
Date Thu, 22 Oct 2015 18:37:27 GMT

    [ https://issues.apache.org/jira/browse/HBASE-14355?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14969611#comment-14969611
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Dave Latham commented on HBASE-14355:
-------------------------------------

Regarding the API, it is adding non-abstract methods.  For 2.0 it would certainly be acceptable.

For a minor version update like 1.3 I'm not certain exactly how "Server-Side Limited API compatibility"
applies to adding a non-abstract method.  Technically if a plugin/coprocessor has subclassed
Scan with the same method and then some client expects the implementation in this patch and
ends up using that plugin/coprocessor it could have unexpected behavior.  That seems farfetched.
 However do we try to maintain exact stability across minor versions for entirely other implementations
of the HBase API (does google or MapR do that)?

However, let's get it done in master first and not let concerns about backports slow that
down.  Anyone have a chance to review or any concerns about the patch or willing to commit?

> Scan different TimeRange for each column family
> -----------------------------------------------
>
>                 Key: HBASE-14355
>                 URL: https://issues.apache.org/jira/browse/HBASE-14355
>             Project: HBase
>          Issue Type: New Feature
>          Components: Client, regionserver, Scanners
>            Reporter: Dave Latham
>            Assignee: churro morales
>             Fix For: 2.0.0, 1.3.0, 0.98.16
>
>         Attachments: HBASE-14355-v1.patch, HBASE-14355-v2.patch, HBASE-14355.patch
>
>
> At present the Scan API supports only table level time range. We have specific use cases
that will benefit from per column family time range. (See background discussion at https://mail-archives.apache.org/mod_mbox/hbase-user/201508.mbox/%3CCAA4mzom00ef5eoXStK0HEtxebY8mQSs61GBVGttgpASpmhQHaw@mail.gmail.com%3E)
> There are a couple of choices that would be good to validate.  First - how to update
the Scan API to support family and table level updates.  One proposal would be to add Scan.setTimeRange(byte
family, long minTime, long maxTime), then store it in a Map<byte[], TimeRange>.  When
executing the scan, if a family has a specified TimeRange, then use it, otherwise fall back
to using the table level TimeRange.  Clients using the new API against old region servers
would not get the families correctly filterd.  Old clients sending scans to new region servers
would work correctly.
> The other question is how to get StoreFileScanner.shouldUseScanner to match up the proper
family and time range.  It has the Scan available but doesn't currently have available which
family it is a part of.  One option would be to try to pass down the column family in each
constructor path.  Another would be to instead alter shouldUseScanner to pass down the specific
TimeRange to use (similar to how it currently passes down the columns to use which also appears
to be a workaround for not having the family available). 



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