Does Riak support Range Queries over binary safe strings?

Jeremiah Peschka jeremiah.peschka at gmail.com
Tue Jul 16 19:46:30 EDT 2013


Not a problem.

MapReduce across an entire keyspace is slow.

MapReduce when provided with a few bucket/key pairs is the same as a
multi-get + processing.

You can combine 2i + MR to get quick processing of data. Although, at that
point, you might as well just process your data on the client side.
Especially if you're just pulling out a slice of bytes.

---
Jeremiah Peschka - Founder, Brent Ozar Unlimited
MCITP: SQL Server 2008, MVP
Cloudera Certified Developer for Apache Hadoop


On Tue, Jul 16, 2013 at 4:13 PM, gbrits <gbrits at gmail.com> wrote:

> Wow, high speed on this list!
>
> I wanted it for near realtime anyway so Map/reduce is out of the question.
> Thought somehow it could be done through Riak Search or directly on
> secondary indices instead of map/reduce.
> Guess not. Oh well, can't have it all.
>
> Thanks
>
>
> 2013/7/17 Jeremiah Peschka [via Riak Users] <[hidden email]<http://user/SendEmail.jtp?type=node&node=4028360&i=0>
> >
>
>> Following up on Alex's comments -
>>
>> If you know which bytes you need to slice, you can store this in a
>> secondary index. You can perform range queries across secondary indices (as
>> well as keys).
>>
>> As long as you're storing your data in a way that allows it to be read by
>> either Erlang or JavaScript, you should be able to query over it in
>> MapReduce. This is typically regarded as a Bad Idea™ since an MR query will
>> need to scan all keys in a bucket (which effectively means scanning the
>> entire cluster) and is best done as an infrequent activity to transform
>> data.
>>
>> ---
>> Jeremiah Peschka - Founder, Brent Ozar Unlimited
>>  MCITP: SQL Server 2008, MVP
>> Cloudera Certified Developer for Apache Hadoop
>>
>>
>> On Tue, Jul 16, 2013 at 3:45 PM, Alexander Sicular <[hidden email]<http://user/SendEmail.jtp?type=node&node=4028359&i=0>
>> > wrote:
>>
>>> I would say no. Riak is generally oblivious as to the content of your
>>> data. Any ranges or other method you would use to query needs to be
>>> explicitly indexed via riak search or secondary indexes. Once you have
>>> found your data you could operate over that data in a map reduce, but I
>>> can't speak to "binary safe" blob operations in either erlang or JavaScript
>>> although I'm inclined to say yes, you would be able to operate over it in
>>> m/r.
>>>
>>> So searching for keys with certain data in the binblob is probably not
>>> gonna happen but once you have a key to feed an m/r you could get a slice
>>> of that value.
>>>
>>> Make sense?
>>> -Alexander
>>>
>>> @siculars
>>> http://siculars.posthaven.com
>>>
>>> Sent from my iRotaryPhone
>>>
>>> On Jul 16, 2013, at 18:17, gbrits <[hidden email]<http://user/SendEmail.jtp?type=node&node=4028359&i=1>>
>>> wrote:
>>>
>>> > First, hello all!
>>> >
>>> > Coming from Redis, I love that you can just put any binary blob in
>>> Redis
>>> > which is just treated as a string. This is possible because Redis
>>> strings
>>> > are what they call 'binary safe'. This makes it possible to return
>>> slices of
>>> > string-encoded binary data, which is super useful for
>>> bitset-operations,
>>> > etc.
>>> >
>>> > I'm investigating Riak and I like it a lot so far. Riak seems to have
>>> range
>>> > queries (on values, as it seems I must make that distinction with
>>> > column-stores), but I'm not sure if strings in Riak are "Binary safe"
>>> in the
>>> > above sense. If not, is there another way to store binary data in Riak
>>> and
>>> > still do range queries over them quickly?
>>> >
>>> > To be exact: I want to do multi-key lookups in Riak, where each
>>> returned
>>> > result should be of format: <key,slice(featureX,start,end)>
>>> >
>>> > Thanks,
>>> > Geert-Jan
>>> >
>>> >
>>> >
>>> > --
>>> > View this message in context:
>>> http://riak-users.197444.n3.nabble.com/Does-Riak-support-Range-Queries-over-binary-safe-strings-tp4028356.html
>>> > Sent from the Riak Users mailing list archive at Nabble.com.
>>> >
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