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https://issues.apache.org/jira/browse/ACCUMULO-3633?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14355184#comment-14355184
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Eric Newton commented on ACCUMULO-3633:
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Gotchas I've learned about over the years:
* {{init}} is/should always called before {{seek}}
* {{seek}} is/should always called before {{hasTop}}
* any time an Iterator returns, it may be torn down and thrown away
* the last returned value from {{getTopKey}} will be provided to {{seek}} after
an iterator stack is re-instantiated
* iterators run at compaction time need to deal with delete entries
* (security) iterators run at compaction time see all Key/Values
* (security) iterators run at scan time may not see all Key/Values based on
visibility
> Please provide information on implementing custom iterators in the
> documentation
> --------------------------------------------------------------------------------
>
> Key: ACCUMULO-3633
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3633
> Project: Accumulo
> Issue Type: Wish
> Components: docs
> Affects Versions: 1.6.0
> Environment: Centos 6.5, Accumulo 1.6.0, CDH 5.
> Reporter: Vaibhav Thapliyal
> Assignee: Josh Elser
> Labels: documentation
> Fix For: 1.7.0
>
> Attachments:
> 0001-ACCUMULO-3633-User-manual-chapter-on-custom-iterator.patch
>
>
> Dear all,
> Can you please provide a documentation regarding creating custom Iterators.
> For example, explain the functionality of the functions inside
> SortedKeyValueIterator and how to override those functions.
> Please explain how these functions are executed (which class calls these
> functions when the iterator executes).
> I would appreciate if these changes are made in your future documentations as
> this would help developers who are new to accumulo to quickly get started on
> writing their own custom iterators which is an essential part of accumulo.
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