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From "Keith Turner (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (ACCUMULO-3294) Need mechanism to update iterator settings
Date Mon, 16 Nov 2015 16:07:11 GMT

    [ https://issues.apache.org/jira/browse/ACCUMULO-3294?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15006841#comment-15006841
] 

Keith Turner commented on ACCUMULO-3294:
----------------------------------------

The way sampling works in 1.8.0-SNAPSHOT is a [good example|https://github.com/apache/accumulo/blob/35cc52e9473ba25b990a5a02731cee11d9301e76/core/src/main/java/org/apache/accumulo/core/client/ScannerBase.java#L179].
 Scans will never use a tables sampling configuration directly (its only used by compactions).
 If a scan wants to use the table config, it must read the table config and pass it to the
scanner.  This has two nice properties.

 * The sampling config is consistent across the entire scan (no need to worry about scan sampling
config changing mid scan).
 * The user can verify the sampling config is as expected.   

Encouraging this pattern would be nice with iterators.   Often client side code is tightly
coupled with a set of iterators.  However when configuring table iterators, clients can not
verify (in a race condition free way) that the scan iterators are what's expected.

> Need mechanism to update iterator settings
> ------------------------------------------
>
>                 Key: ACCUMULO-3294
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-3294
>             Project: Accumulo
>          Issue Type: Improvement
>          Components: client
>            Reporter: John Vines
>            Assignee: Jonathan Park
>             Fix For: 1.8.0
>
>         Attachments: bug3294.patch, bug3294.patch.1
>
>
> Currently our API supports attachIterator, removeIterator, and getIteratorSettings. There
is no mechanism to directly change an iterators settings.



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