On 28 Nov 2011, at 20:16, suresh chandran wrote:
> May be I can make my statement clear :) I store my devices values in buckets
> named after OS (say windows/ linux) with the device id's as keys. I want to
> get the devices for a list of device ids . From what I see, the fetch API
> signature takes in bucket name and key. (Client.fetch("windows", "D1"). Is
> there a way where I can get Client.fetch("windows", <Collection fo keys>?
There is no multi-fetch from Riak right now. You can either fetch your
individual keys (serially on in parallel) or run a Map/Reduce. In most case the
Map/Reduce will be slower (though the API is simpler, I suppose.)
Use IRiakClient.mapReduce().addInput(bucket, key).addInput(bucket,
key2)…(repeat!) I guess this is ripe for a convenience method that takes (as
you suggest) addInputs(bucket, Collection<String> keys), so I'll add that to
the features list.
Or just fetch all your keys using fetch.
I guess it would be possible to add a bulk fetch API to the Riak Java Client
that spawns a configurable number of threads to fetch a bunch of keys in
parallel, but right now that is left as an exercise for the reader :)
Cheers
Russell
>
> Thanks
> Suresh C Nair
> From: suresh chandran <[email protected]>
> To: "[email protected]" <[email protected]>
> Sent: Monday, November 28, 2011 2:53 PM
> Subject: Multiple keys to fetch in a Java client
>
> HI,
>
> I am storing values of a devices under a particular OS. I want to fetch the
> list of all vallues, based on the key list. What I see if that, I can fetch
> the value one by one using the FETCH. Am using the HttpClient in Java. How do
> I go about this? Assume I am tryign to reach the same behavior like query
> that has "CONTAINS(key1, key2...). Is there a way to do this? or we can fetch
> the values only one by one. I do see that Map-reduce, makes use of the list
> fo keys, but am not sure if it is applicable in my case, as it ia simple
> fetch with collection of / list of keys.
>
> Thanks
> Suresh C Nair
>
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