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From "Jeremiah Jordan (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6477) Partitioned indexes
Date Mon, 31 Mar 2014 18:54:21 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13955527#comment-13955527
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Jeremiah Jordan commented on CASSANDRA-6477:
--------------------------------------------

[~benedict] two threads update age = null.  generate tombstones {{24, user1->null}}, two
of them, so those are OK and not a problem, updated to the same value, we also need to generate
{{null: user1}} as an append to the index.  Then update age=25 generates tombstone {{null,
user1->25}} and age=26 generates tombstone {{null, user1->26}}.  Those two tombstones
will be resolved on compaction/memtable clash, or when someone asks for age=null as a query.
 This will require keeping track of null columns in the index.  Something similar would need
to be done for a full delete of the row.

> Partitioned indexes
> -------------------
>
>                 Key: CASSANDRA-6477
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6477
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: API, Core
>            Reporter: Jonathan Ellis
>             Fix For: 3.0
>
>
> Local indexes are suitable for low-cardinality data, where spreading the index across
the cluster is a Good Thing.  However, for high-cardinality data, local indexes require querying
most nodes in the cluster even if only a handful of rows is returned.



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