Riak: Create index on key via Java/Scala

Question

I have a bucket on riak in which I store simple Timestamp -> String values in this way:

val riakClient = RiakFactory.newClient(myHttpClusterConfig) val myBucket = riakClient.fetchBucket(name).execute myBucket.store(timestamp.toString, value).withoutFetch().w(1).execute

What I need to do now is to add an index on the keys. I tried defining a Java POJO in this way:

public class MyWrapper { @RiakIndex(name="timestamp_index") @RiakKey public String timestamp; public String value; public MyWrapper(String timestamp, String value) { this.timestamp = timestamp; this.value = value; } }

and then running

myBucket.store(new MyWrapper(timestamp.toString, value)).withoutFetch().w(1).execute

The problem of this approach is that in riak the actual value is stored as a json object:

{"value":"myvalue"}

while I would simply need to store the myvalue string. Is there any way to achieve this? I can't see any index(name) method when executing store, and I can't see any annotations like @RiakKey but for values.

vad · Accepted Answer · 2014-06-28 07:34:08Z

You can create a RiakObject using a RiakObjectBuilder, and then add the index on that:

val obj = RiakObjectBuilder.newBuilder(bucketName, myKey) .withValue(myValue) .addIndex("timestamp_index", timestamp) .build myBucket.store(obj).execute

Joe · Accepted Answer · 2014-06-27 23:02:01Z

If I understand what you are trying to do, you want the key/value pair "1403909549"/"Some Value" to be indexed by timestamp_index="1403909549" so that you can query specific times or ranges of times.

If that is the case, you do not need to explicitly add an index, you can query the implicit index $KEY in the same manner you would any other index.

Since all keys that Riak stores in LevelDB are indexed implicitly, I don't think a method was exposed to index them again explicitly.

Hey Joe, thank you for your answer, I didn't know of the implicit $KEY index, +1 for that. Your solution would work if I had to store only these Timestamp -> String values in myBucket, but unfortunately I have other keys with a different semantics that I don't want to keep into consideration when querying on timestamp_index

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