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From "He Liangliang (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-13215) A limit on the raw key values is needed for each next call of a scanner
Date Fri, 13 Mar 2015 03:02:38 GMT

    [ https://issues.apache.org/jira/browse/HBASE-13215?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14359850#comment-14359850
] 

He Liangliang commented on HBASE-13215:
---------------------------------------

Thanks, [~jonathan.lawlor]. The invisibility sometimes is undesirable, the application actually
want to know what happens and need to response to their client, especially there is strict
timeout in online services.
In other cases, there is one more requirement. The application want to know the (may be invisible
if limit is reached) scanner position, and reopen the scanner later with this position (this
does not have best performance but no state is needed for all backends includes RS). We had
a patch for 0.94 for these two requirements.

> A limit on the raw key values is needed for each next call of a scanner
> -----------------------------------------------------------------------
>
>                 Key: HBASE-13215
>                 URL: https://issues.apache.org/jira/browse/HBASE-13215
>             Project: HBase
>          Issue Type: Improvement
>          Components: Scanners
>            Reporter: He Liangliang
>            Assignee: He Liangliang
>
> In the current scanner next, there are several limits: caching, batch and size. But there
is no limit on raw data scanned, so the time consumed by a next call is unbounded. For example,
many consecutive deleted or filtered out cells will leads to a socket timeout. This can make
user code get stuck.



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