Hi, In addition to the $key index, there is also a $bucket index available by default. This contains the name of the bucket, and can be used to get all keys in a specific bucket.
Best regards, Christian On 12 Feb 2013, at 22:39, Jeremiah Peschka <jeremiah.pesc...@gmail.com> wrote: > As best as I understand the magical $key index, you need to provide a range > in order to query anything from the index. A RiakBucketKeyInput accepts a > bucket/key pair - you can add many of these to an MR input phase if you > already know which keys in a bucket need to be acted upon. > > Riak's secondary indices only allow for two operatios - exact match and range > scan (see the message description if you're interested [1]). To get a full > range scan, you'll want to pick a range_max value that is outside the bounds > of your largest key. If you know you're only dealing with ASCII characters > you can easily pick an ASCII character [2] that's outside the bounds of your > data set. This gets trickier if you have to deal with Unicode data. > > [1]: > http://docs.basho.com/riak/latest/references/apis/protocol-buffers/PBC-Index/ > [2]: http://www.asciitable.com/ > > --- > Jeremiah Peschka - Founder, Brent Ozar Unlimited > MCITP: SQL Server 2008, MVP > Cloudera Certified Developer for Apache Hadoop > > > On Tue, Feb 12, 2013 at 2:24 PM, Kevin Burton <rkevinbur...@charter.net> > wrote: > Is there a reason why you selected a range and not just the bucket and key > (in the example)? My concern is that I don’t want to hard-code any > dependencies or fore-knowledge in the code if possible. Using a range assumes > that all of the keys are in the range. As I see it if you just specify the > bucket and key there is no “assumption”. Right? > > > > From: Jeremiah Peschka [mailto:jeremiah.pesc...@gmail.com] > Sent: Tuesday, February 12, 2013 1:52 PM > > > To: Kevin Burton > Cc: riak-users > Subject: Re: ListKeys or MapReduce > > > > Oh, and an example can be found https://gist.github.com/peschkaj/4772825 > > > > --- > > Jeremiah Peschka - Founder, Brent Ozar Unlimited > > MCITP: SQL Server 2008, MVP > > Cloudera Certified Developer for Apache Hadoop > > > > On Tue, Feb 12, 2013 at 11:44 AM, Jeremiah Peschka > <jeremiah.pesc...@gmail.com> wrote: > > ...and fixed! > > > > You can get this right now if you're adventurous and want to build > CorrugatedIron from source by grabbing the develop branch [1]. We have > several other issues to clean up and verify before we release CI 1.1.1 in the > next day or so. Or you can download it from [2] if you don't want to build > yourself and don't want to wait for NuGet. Once we put 1.1.1 to NuGet we'll > respond to this thread or email you directly. > > > > I make no guarantees that the new DLL won't eat your hard drive or turn your > computer into a killer robot. > > > > [1]: https://github.com/DistributedNonsense/CorrugatedIron/tree/develop > > [2]: > http://clientresources.brentozar.com.s3.amazonaws.com/CorrugatedIron-111-alpha.zip > > > > --- > > Jeremiah Peschka - Founder, Brent Ozar Unlimited > > MCITP: SQL Server 2008, MVP > > Cloudera Certified Developer for Apache Hadoop > > > > On Tue, Feb 12, 2013 at 11:13 AM, Jeremiah Peschka > <jeremiah.pesc...@gmail.com> wrote: > > Good news! You've found a bug in CorrugatedIron. Because of index naming, we > muck index names to have a suffix of _bin or _int, depending on the index > type. This shouldn't be happening on $key, but it is. I'll create a github > issue and get that taken care of. > > > > --- > > Jeremiah Peschka - Founder, Brent Ozar Unlimited > > MCITP: SQL Server 2008, MVP > > Cloudera Certified Developer for Apache Hadoop > > > > On Tue, Feb 12, 2013 at 7:56 AM, Kevin Burton <rkevinbur...@charter.net> > wrote: > > I forgot to mention that when I execute this code I get the error: > > > > {not_found, > > {<<"products">>, > > <<"$keys">>}, > > undefined}}}:[{mochijson2, > > json_encode,2, > > [{file, > > > "src/mochijson2.erl"}, > > {line,149}]}, > > {mochijson2, > > > '-json_encode_array/2-fun-0-', > > 3, > > [{file, > > > "src/mochijson2.erl"}, > > {line,157}]}, > > {lists,foldl,3, > > [{file,"lists.erl"}, > > {line,1197}]}, > > {mochijson2, > > json_encode_array,2, > > [{file, > > > "src/mochijson2.erl"}, > > {line,159}]}, > > {riak_kv_pb_mapred, > > process_stream,3, > > [{file, > > > "src/riak_kv_pb_mapred.erl"}, > > {line,97}]}, > > {riak_api_pb_server, > > process_stream,5, > > [{file, > > > "src/riak_api_pb_server.erl"}, > > {line,227}]}, > > {riak_api_pb_server, > > handle_info,2, > > [{file, > > > "src/riak_api_pb_server.erl"}, > > {line,158}]}, > > {gen_server, > > handle_msg,5, > > [{file, > > "gen_server.erl"}, > > {line,607}]}] - > CommunicationError > > > > > > From: riak-users [mailto:riak-users-boun...@lists.basho.com] On Behalf Of > Kevin Burton > Sent: Tuesday, February 12, 2013 9:48 AM > To: 'Jeremiah Peschka' > Cc: 'riak-users' > Subject: RE: ListKeys or MapReduce > > > > The name is “$keys”? Something like: > > > > using (IRiakEndPoint cluster = > RiakCluster.FromConfig("riakConfig")) > > { > > IRiakClient riakClient = cluster.CreateClient(); > > RiakBucketKeyInput bucketKeyInput = new RiakBucketKeyInput(); > > bucketKeyInput.AddBucketKey(productBucketName, "$keys"); > > RiakMapReduceQuery query = new RiakMapReduceQuery() > > .Inputs(bucketKeyInput) > > .MapJs(m => m.Name("Riak.mapValuesJson").Keep(true)); > > RiakResult<RiakMapReduceResult> result = > riakClient.MapReduce(query); > > if (result.IsSuccess) > > { > > > > > > From: Jeremiah Peschka [mailto:jeremiah.pesc...@gmail.com] > Sent: Tuesday, February 12, 2013 9:18 AM > To: Kevin Burton > Cc: riak-users > Subject: Re: ListKeys or MapReduce > > > > It would be queried like any other index as an MR input. I'll create an issue > and will try to get this in some time in the next few days - no promises, > though. > > > > --- > > Jeremiah Peschka - Founder, Brent Ozar Unlimited > > MCITP: SQL Server 2008, MVP > > Cloudera Certified Developer for Apache Hadoop > > > > On Tue, Feb 12, 2013 at 7:09 AM, Kevin Burton <rkevinbur...@charter.net> > wrote: > > I will read the other URLs that you mentioned. Thank you. > > > > Would you mind giving a short example (preferably using CI) of the $keys > index? > > > > From: Jeremiah Peschka [mailto:jeremiah.pesc...@gmail.com] > Sent: Tuesday, February 12, 2013 8:52 AM > To: Kevin Burton > Cc: riak-users > Subject: Re: ListKeys or MapReduce > > > > They're both pretty crappy in terms of performance - they read all data off > of disk. If you're using LevelDB you can use the $keys index to pull back > just the keys that in a single bucket. > > > > A better approach is to maintain a separate bucket - e.g. DocumentCount - > that is used for counting documents. Unfortunately, you can't guarantee > transactional consistency around counts in Riak today, so you'll want to move > maintaining the counts out of Riak and into something else. If you search the > list archives [1], you'll find that Redis has been mentioned as a good way to > solve this problem - counters are stored in Redis and flushed to Riak on a > regular schedule. Because of the lack of consistency (especially around > MapReduce operations), Riak isn't the best choice if you require > counters/aggregations to be stored in the database. > > > > Once CRDTs [2] make it into mainstream Riak, you can make use of those data > structures to implement distributed counters in Riak. > > > > [1]: http://riak.markmail.org > > [2]: http://vimeo.com/52414903 > > > > --- > > Jeremiah Peschka - Founder, Brent Ozar Unlimited > > MCITP: SQL Server 2008, MVP > > Cloudera Certified Developer for Apache Hadoop > > > > On Mon, Feb 11, 2013 at 10:30 AM, <rkevinbur...@charter.net> wrote: > > Say I need to determine how many document there are in my database. For a > CorrugatedIron application I can do ListKeys and get the warning that it is > an expensive operation or I can do a MapReduce query. Which is the the least > expensive? Is there an option that I am missing? > > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > > > > > > > > > > > > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
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