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From "Sylvain Lebresne (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6477) Materialized Views (was: Global Indexes)
Date Fri, 17 Jul 2015 15:08:09 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6477?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14631440#comment-14631440
] 

Sylvain Lebresne commented on CASSANDRA-6477:
---------------------------------------------

I don't really think the cost of replaying the coordinator BL matters that much. We'll only
if less than a quorum of node don't answer a particular query, which should be pretty rare
unless you have bigger problems with your cluster. And given the local BL has a cost on every
write, even if small, I don't think that from a performance perspective a local BL is a win.

That said, I hadn't seen we'd decided to go with pairing of base replica to MV replica. Doing
so does justify a local BL (another option has always been to fan out to every MV replica,
and since this ticket desperately miss a good description of what exact algorithm is actually
implemented, I wasn't sure which option we went with).

> Materialized Views (was: Global 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
>            Assignee: Carl Yeksigian
>              Labels: cql
>             Fix For: 3.0 beta 1
>
>         Attachments: test-view-data.sh, users.yaml
>
>
> 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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