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Sylvain Lebresne commented on CASSANDRA-6477:
---------------------------------------------
bq. When we actually add support for null partition keys we can lift this
requirement.
I do want to note that there *is* a technical problem with allowing null in the
MV primary keys (partition key or clustering columns alike), and that is TTLs.
More precisely, if a column {{c}} in the MV PK has a TTL, we would need to
update the MV once {{c}} expires, replacing the entry by one where {{c}} is now
{{null}}. And a priori, I don't see an even remotely efficient way to deal with
that (keeping in mind that we collect expired column lazily, *not* when they
expire).
That is, I agree that requiring {{IS NOT NULL}} for all *primary* key columns
is the safe option for 3.0, but just wanted to note that the TTL problem above
seems to me like a big obstacle in removing that requirement.
> 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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