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From Sonny Heer <sonnyh...@gmail.com>
Subject Re: extending multiget
Date Fri, 18 Jun 2010 16:48:27 GMT
Assume a map/reduce program which needs to update some values during
ingest, and needs to perform read operations on 100 keys each of which
have say 50 different columns.  This happens many times for a given
reduce task in the cluster.  Shouldn't that be handled by the server
as a single call?


On Thu, Jun 17, 2010 at 5:54 PM, Jonathan Ellis <jbellis@gmail.com> wrote:
> No.  At that point you basically have no overhead advantage vs just
> doing multiple single-row requests.
>
> On Thu, Jun 17, 2010 at 2:39 PM, Sonny Heer <sonnyheer@gmail.com> wrote:
>> Any plans for this sort of call?
>>
>>
>> Instead of:
>>
>>    public Map<String,List<ColumnOrSuperColumn>> multiget_slice(String
>> keyspace, List<String> keys, ColumnParent column_parent,
>> SlicePredicate predicate, ConsistencyLevel consistency_level) throws
>> InvalidRequestException, UnavailableException, TimedOutException,
>> TException;
>>
>> ---
>>
>>    public Map<String,List<ColumnOrSuperColumn>> multiget_slice(String
>> keyspace, Map<String, List<String>> keyColNames, ColumnParent
>> column_parent, ConsistencyLevel consistency_level) throws
>> InvalidRequestException, UnavailableException, TimedOutException,
>> TException;
>>
>> ---
>>
>> where the keyColNames explicitly maps which column names to retrieve
>> for a given key, instead of a column slice on all keys.
>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of Riptano, the source for professional Cassandra support
> http://riptano.com
>

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