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From "Stu Hood (JIRA)" <j...@apache.org>
Subject [jira] Commented: (CASSANDRA-749) Secondary indices for column families
Date Thu, 15 Apr 2010 21:22:57 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-749?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12857541#action_12857541
] 

Stu Hood commented on CASSANDRA-749:
------------------------------------

> If the property is NOT the original, base row key, then not matter what kind of index
you have, you 
> need to read all the results to sort in the desired order 
I think we agree that we would never want to allow this. Instead, for an index read with the
non-local index, I would propose that the order _must_ be defined beforehand. If, for instance,
you wanted to do an index read in base row key order, then you would need to define an index
with a compound key of 'basevalue|basekey', so that each basevalue (presumably low cardinality)
would be sorted by the basekey.

For range queries over a few basevalues, there would be some merging involved, but it would
_not_ need a sort, and it wouldn't necessarily involve the entire cluster. For instance, for
a range query for index values between 1969 and 1970, you would have two basevalues to consider,
and so you would want to perform a merge of the (pre-sorted) basekeys for 1969 and 1970.

EDIT: sorry, I facepalmed after writing this comment, and deleted it briefly: the compound
key would be 'basevalue|basekey', which changes a few things.

> Secondary indices for column families
> -------------------------------------
>
>                 Key: CASSANDRA-749
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-749
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: Core
>            Reporter: Gary Dusbabek
>            Assignee: Gary Dusbabek
>            Priority: Minor
>             Fix For: 0.8
>
>         Attachments: 0001-simple-secondary-indices.patch, views-discussion-2.txt, views-discussion.txt
>
>


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