Re: omap functions in librados.h

[Xiaopong Tran <xiaopong.tran@gmail.com>]

On 08/18/2012 04:13 AM, Gregory Farnum wrote:
> On Fri, Aug 17, 2012 at 1:09 PM, Wido den Hollander <wido@widodh.nl> wrote:
>>
>>
>> On 08/17/2012 09:54 PM, Gregory Farnum wrote:
>>>
>>> On Fri, Aug 17, 2012 at 12:36 PM, Wido den Hollander <wido@widodh.nl>
>>> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I'm looking for the omap functions in librados.h, but they only seem to
>>>> be
>>>> implemented in librados.hpp?
>>>>
>>>> I want to store about 6000 objects in a RADOS pool, but I want to give
>>>> them
>>>> some attributes I can query for, this should be possible with the omap
>>>> functionality, shouldn't it?
>>>
>>> What do you mean, query for? You can look at an object and ask if it
>>> has "foo=bar" in its omap, but you can't say "give me all objects with
>>> 'foo=bar'".
>>>
>>
>> Ah, I must have understood that differently. I thought that leveldb was
>> added so you could give objects attributes you could query.
> No, leveldb is just a nice fast store — sorry!
>
>> So yes: "Give me all objects that have foo=bar"
>>
>> I thought I saw some discussion regarding this.
>>
>> Any ideas besides setting up a own external database with this information?
>
> Well, you could maintain the data in a single rados object, if it
> doesn't need to get too large. Or Eleanor (one of our friendly
> interns!) has been writing a prototype distributed b-tree database
> thingy that you might want to look at.
> But there are presently no plans to (or ideas of how to) implement a
> generic query-able set of attributes which are co-located with nodes.
> -Greg
> --

Where is this distributed b-tree located? Is it open source as well?
I'd be very interested too.

Regards,

Xiaopong


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