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Sylvain Lebresne commented on CASSANDRA-6477:
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bq. Because one isn't implicitly a hot spot
Ok, gotcha, MV table where the partition key is a single column that is not a
PK from the base table will create implicit hot spots. I'm personally happy to
disallow that case. That's still a very specific case: MV tables with multiple
partition key columns where one of them is a PK in the base table (but not all
of them are) don't have this problem, so the the underlying question of how we
support that is still open.
bq. we would have to insert new NULL values after a TTL expired
Good point. I can definitively see how TTLs are a problem for including non-PK
columns from the base table into a MV PK. That said, as far as I can tell
that's a problem even with a single column that is not in the original PK. Yet,
it's supposed to be supported by the patch. How does it work? What happen once
that column expires?
bq. This means that we will have to insert a NULL value for all unset columns,
as well as all tombstone'd columns, since regular columns are not explicitly
null.
That part I don't follow.
> 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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