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https://issues.apache.org/jira/browse/CASSANDRA-6383?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13853975#comment-13853975
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Sylvain Lebresne commented on CASSANDRA-6383:
---------------------------------------------
Btw, forgot to mention that since for a map we don't allow indexing both the
key and value, there is the question of what to do with a "CREATE INDEX IF
EXISTS" if there is an existing index on values and the new create attempts to
create an index on keys. The current patch reject the query, because that feels
the most reasonable thing to do, but that does mean that even with IF EXISTS a
create index can fail, which might be annoying I suppose (not a big deal
really, just wanted to mention it).
> Secondary indexing of map keys
> ------------------------------
>
> Key: CASSANDRA-6383
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6383
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Sylvain Lebresne
> Assignee: Sylvain Lebresne
> Fix For: 2.1
>
> Attachments: 6383.txt
>
>
> CASSANDRA-4511 started adding secondary indexing for collections, but didn't
> wired map key indexing because this requires generalizing a bit the 2ndary
> index API to support 2 indexes on the same column. And since that's not
> entirely related to the initial problem of CASSANDRA-4511, let's tackle this
> last part here.
> I'll note that one other is the syntax. For selection, I propose
> {noformat}
> SELECT * FROM foo WHERE myMap CONTAINS KEY 'bar';
> {noformat}
> (but that assumes we use CONTAINS in CASSANDRA-4511, if we use IN, we'll need
> something else)
> For declaring indexes I'm less inspired. We could have something like
> {noformat}
> CREATE INDEX ON foo(myMap KEYS)
> {noformat}
> but maybe someone has a better idea?
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