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From "Sylvain Lebresne (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6477) Materialized Views (was: Global Indexes)
Date Tue, 14 Jul 2015 14:48:09 GMT

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

bq. NULL, however, is not something people think about since it's the default value implicitly
for Cassandra.

Again, I'm not trying to say that it's not something we should consider. I'm mainly saying
that imo we should do CASSANDRA-9796 anyway so we don't have the internal limitation. Maybe
we can impose limitations for the sake of protecting against foot-shooting, like requiring
that at least one column of the MV partition key is a primary key column of the base table
(whithout requiring all of them to be).

bq.  If you are writing to a table with RF=3 and only one replica has a value but the other
two do not then we will make one MV replica have a defined partition key and the other two
replicas will have a NULL

Not sure I follow. Nulls should just be "just another value" and there should really be any
special casing for them. How is what you say different from writing a new value at RF=3 and
only one replica getting the new value?


> 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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