I have no problem doing this w 2.0.5 - what version of C* are you using? Or
maybe I don't understand your data model... attach 'creates' if you don't
mind.
ml
On Thu, Mar 13, 2014 at 9:24 AM, David Savage <davemssav...@gmail.com>wrote:
> Hi Peter,
>
> Thanks for the help, unfortunately I'm not sure that's the problem, the id
> is the primary key on the documents table and the timestamp is the
> primary key on the eventlog table
>
> Kind regards,
>
>
> Dave
>
> On Thursday, 13 March 2014, Peter Lin <wool...@gmail.com> wrote:
>
>>
>> it's not clear to me if your "id" column is the KEY or just a regular
>> column with secondary index.
>>
>> queries that have IN on non primary key columns isn't supported yet. not
>> sure if that answers your question.
>>
>>
>> On Thu, Mar 13, 2014 at 7:12 AM, David Savage <davemssav...@gmail.com>wrote:
>>
>>> Hi there,
>>>
>>> I'm experimenting using cassandra and have run across an error message
>>> which I need a little more information on.
>>>
>>> The use case I'm experimenting with is a series of document updates
>>> (documents being an arbitrary map of key value pairs), I would like to find
>>> the latest document updates after a specified time period. I don't want to
>>> store many copies of the documents (one per update) as the updates are
>>> often only to single keys in the map so that would involve a lot of
>>> duplicated data.
>>>
>>> The solution I've found that seems to fit best in terms of performance
>>> is to have two tables.
>>>
>>> One that has an event log of timeuuid -> docid and a second that stores
>>> the documents themselves stored by docid -> map<string, string>. I then run
>>> two queries, one to select ids that have changed after a certain time:
>>>
>>> SELECT id FROM eventlog WHERE timestamp>=minTimeuuid($minimumTime)
>>>
>>> and then a second to select the actual documents themselves
>>>
>>> SELECT id, data FROM documents WHERE id IN (0, 1, 2, 3, 4, 5, 6, 7…)
>>>
>>> However this then explodes on query with the error message:
>>>
>>> "Cannot restrict PRIMARY KEY part id by IN relation as a collection is
>>> selected by the query"
>>>
>>> Detective work lead me to these lines in
>>> org.apache.cassandra.cql3.statementsSelectStatement:
>>>
>>> // We only support IN for the last name and for
>>> compact storage so far
>>> // TODO: #3885 allows us to extend to non compact as
>>> well, but that remains to be done
>>> if (i != stmt.columnRestrictions.length - 1)
>>> throw new
>>> InvalidRequestException(String.format("PRIMARY KEY part %s cannot be
>>> restricted by IN relation", cname));
>>> else if (stmt.selectACollection())
>>> throw new
>>> InvalidRequestException(String.format("Cannot restrict PRIMARY KEY part %s
>>> by IN relation as a collection is selected by the query", cname));
>>>
>>> It seems like #3885 will allow support for the first IF block above, but
>>> I don't think it will allow the second, am I correct?
>>>
>>> Any pointers on how I can work around this would be greatly appreciated.
>>>
>>> Kind regards,
>>>
>>> Dave
>>>
>>
>>
