[
https://issues.apache.org/jira/browse/ACCUMULO-4500?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15587868#comment-15587868
]
Christopher Tubbs commented on ACCUMULO-4500:
---------------------------------------------
I would like to suggest we avoid thinking about this feature in terms of
histograms. Histograms are only one possible feature of what was discussed on
the mailing list thread. Granted, it was the feature which started the
conversation, but the concepts, APIs, and features, we'd have to implement to
support histograms, should be much more generic, supporting a wider variety of
use cases.
The basic functionality which would be needed to support this feature, as
discussed on the mailing list, could be generalized simply as "named counters",
and I think for simplicity sake, we should limit the feature to be a mapping of
names (type: String) to counts (type: signed Long).
Additionally, I was thinking about this today, and I think it would be a good
idea that when this information is exposed in the client API, it should be
retrievable through a user-supplied aggregation/combiner function. The
reasoning for this is that client code doesn't normally deal with things at the
granularity of files, but rather, the granularity of tablets, ranges, and
tables. That should probably be true for any new API to retrieve these data as
well. And, if that's the case, there will need to be some mechanism to
aggregate the data from multiple files for the requested range/tablet/table. A
summation function would probably be the most common, but certainly not the
only useful aggregation function.
> Implement visibility histograms as a table feature
> --------------------------------------------------
>
> Key: ACCUMULO-4500
> URL: https://issues.apache.org/jira/browse/ACCUMULO-4500
> Project: Accumulo
> Issue Type: New Feature
> Components: client, tserver
> Reporter: Josh Elser
>
> Add support to quickly extract a histogram of all of the visibilities stored
> in an Accumulo table.
> DISCUSS:
> https://lists.apache.org/thread.html/df5e764362a95277344fd2731a432e9fafc60595e7d30015d9a56b9c@%3Cdev.accumulo.apache.org%3E
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
