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https://issues.apache.org/jira/browse/CASSANDRA-4179?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13407619#comment-13407619
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Jonathan Ellis commented on CASSANDRA-4179:
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bq. since we decided to not support it for composite comparators, it's
consistent to just say we don't support it here
+1
bq. if we have more than one key alias, then we don't return any to thrift
sgtm.
bq. there is no way to do a 'IN' on the full row key
Hmm, that's a tricky one. The most natural way to express this in SQL would be
{code}
SELECT * FROM timeline WHERE (name = 'foo' AND month = 1) OR (name = 'bar' AND
month = 4)
{code}
or possibly
{code}
SELECT * FROM timeline WHERE name = 'foo' AND month = 1
UNION ALL
SELECT * FROM timeline WHERE name = 'bar' AND month = 4
{code}
I think the original argument against supporting UNION still holds -- i.e.,
that it's too general, and allows queries against completely different indexes
or even different tables, to be smashed together, which is not our goal. But
if we can figure out how to parse and recognize the OR syntax that would be my
preference.
bq. {{SELECT * FROM timeline WHERE token(name, month) > token('bar', 4)}}
LGTM.
> Add more general support for composites (to row key, column value)
> ------------------------------------------------------------------
>
> Key: CASSANDRA-4179
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4179
> Project: Cassandra
> Issue Type: Sub-task
> Components: API
> Reporter: Sylvain Lebresne
> Assignee: Sylvain Lebresne
> Priority: Minor
> Attachments: 4179.txt
>
>
> Currently CQL3 have a nice syntax for using composites in the column name
> (it's more than that in fact, it creates a whole new abstraction but let's
> say I'm talking implementation here). There is however 2 other place where
> composites could be used (again implementation wise): the row key and the
> column value. This ticket proposes to explore which of those make sense for
> CQL3 and how.
> For the row key, I really think that CQL support makes sense. It's very
> common (and useful) to want to stuff composite information in a row key.
> Sharding a time serie (CASSANDRA-4176) is probably the best example but there
> is other.
> For the column value it is less clear. CQL3 makes it very transparent and
> convenient to store multiple related values into multiple columns so maybe
> composites in a column value is much less needed. I do still see two cases
> for which it could be handy:
> # to save some disk/memory space, if you do know it makes no sense to
> insert/read two value separatly.
> # if you want to enforce that two values should not be inserted separatly.
> I.e. to enforce a form of "constraint" to avoid programatic error.
> Those are not widely useful things, but my reasoning is that if whatever
> syntax we come up for "grouping" row key in a composite trivially extends to
> column values, why not support it.
> As for syntax I have 3 suggestions (that are just that, suggestions):
> # If we only care about allowing grouping for row keys:
> {noformat}
> CREATE TABLE timeline (
> name text,
> month int,
> ts timestamp,
> value text,
> PRIMARY KEY ((name, month), ts)
> )
> {noformat}
> # A syntax that could work for both grouping in row key and colum value:
> {noformat}
> CREATE TABLE timeline (
> name text,
> month int,
> ts timestamp,
> value1 text,
> value2 text,
> GROUP (name, month) as key,
> GROUP (value1, value2),
> PRIMARY KEY (key, ts)
> )
> {noformat}
> # An alternative to the preceding one:
> {noformat}
> CREATE TABLE timeline (
> name text,
> month int,
> ts timestamp,
> value1 text,
> value2 text,
> GROUP (name, month) as key,
> GROUP (value1, value2),
> PRIMARY KEY (key, ts)
> ) WITH GROUP (name, month) AS key
> AND GROUP (value1, value2)
> {noformat}
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