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https://issues.apache.org/jira/browse/HBASE-3607?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13011346#comment-13011346
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Gary Helmling commented on HBASE-3607:
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I posted a review of this on review board:
https://review.cloudera.org/r/1624/
(We really need to get the damn email spam scoring fixed).
> Cursor functionality for results generated by Coprocessors
> ----------------------------------------------------------
>
> Key: HBASE-3607
> URL: https://issues.apache.org/jira/browse/HBASE-3607
> Project: HBase
> Issue Type: New Feature
> Components: coprocessors
> Reporter: Himanshu Vashishtha
> Attachments: patch-2.txt
>
>
> I tried to come up with a scanner like functionality for results generated by
> coprocessors at region level.
> This is just a poc, and it will be good to have your comments on it.
> It has support for both Incremental and In-memory Result sets. Attached is a
> patch that has a test case for an incremental result (i.e., client receives a
> cursorId from the CP core method, it instantiates a cursor object and
> iterates over the result set. He can set a cache limit on the CursorCallable
> object to reduce the number of rpc --> just like scanners.
> In its current state, it has some limitations too :)), like, it is region
> specific only, i.e., one can instantiate and use cursor at one region only
> (and that region is determined by the input row while instantiating the
> cursor). I will try to expand it so that it can have atleast a sequential
> access to other regions, but as I said, I want the opinion of experts to know
> whether this approach really makes some sense or not.
> I have tested it with the inbuilt testing framework on my laptop only.
> It will be good if I copy the use case here in the description too:
> Test table has rows like:
> /**
> * The scenario is that I have these rows keys in the test table:
> 'aaa-123'
> 'aaa-456'
> 'abc-111'
> 'abd-111'
> 'abd-222'
> & I want to return:
> ('aaa', 2)
> ('abc', 1)
> ('abd', 2)
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