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HBase, mail # dev - HBase - Secondary Index


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Re: HBase - Secondary Index
Doug Meil 2012-12-05, 21:58

re:  "It seems everybody wants secondary indexes in HBase. The problem is
that most folks don't agree what that actually means."

Agreed.  And often times when people say "secondary indexing" they may be
talking about an access path on something that isn't represented in the
key.  So you'd not just need a "row key schema" (which is what we were
talking about in HBASE-7221), but a schema for the columns too.
On 12/5/12 4:03 PM, "lars hofhansl" <[EMAIL PROTECTED]> wrote:

>I'd say "it depends".
>It seems everybody wants secondary indexes in HBase. The problem is that
>most folks don't agree what that actually means.
>
>The most interesting problem and discussion point (IMHO) is that HBase
>would need some form of schema description.
>
>See also HBASE-7221. Assuming we had something like that, it could be a
>building block for a simple built-in secondary index solution.
>
>In the end you're probably right and we cannot prescribe a single
>secondary index solution that will fit all use cases.
>
>-- Lars
>
>
>----- Original Message -----
>From: Jonathan Hsieh <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Cc:
>Sent: Wednesday, December 5, 2012 11:23 AM
>Subject: Re: HBase - Secondary Index
>
>I personally feel that we should only add the primitive apis necessary to
>make this work (and if non are required, all the better!), and to try to
>keep secondary indexing work it as a separate project on top of hbase
>because there are many possible valid architectures and  implementations.
>
>I have two question areas -- one touched upon in previous messages -- what
>logging and how do we get consistency guarantee's do we get bewteen the
>index and primary?
>
>The other has to do with scalability. I'm not sure I interpreted the
>slides
>correctly, but from the slides 8 and 13, is the architecture such that
>each
>primary table region has a corresponding index table region?
>
>Is slide 14 a comparison of a full table scan vs the indexed lookups on 4
>rs's?  What happens if we go up to 20, or 100 rs's?  If I'm right about
>the
>per index region per table region, I have a feeling this isn't going to
>scale well with a large number of regions (since it would potentially have
>to talk to each region and essentially every region server).
>
>Jon.
>
>On Wed, Dec 5, 2012 at 9:54 AM, Anoop John <[EMAIL PROTECTED]> wrote:
>
>> I mean HBase devs to work on having sec indexing available with the
>>HBase
>> distribution...  Now I guess many users of HBase implement different
>>kinds
>> of sec indexing ..:)
>>
>> We @Huawei would be happy to provide our support in it as per the
>>interest
>> from the community.. :)
>>
>> -Anoop-
>>
>> On Wed, Dec 5, 2012 at 9:29 PM, Andrey Stepachev <[EMAIL PROTECTED]>
>>wrote:
>>
>> > Can you explain, what you mean under 'HBase community version with sec
>> > indexing in it'. You will wait, until someone implements the same
>> algorithm
>> > in trunk hbase, or?
>> >
>> >
>> > On Wed, Dec 5, 2012 at 4:55 PM, Anoop Sam John <[EMAIL PROTECTED]>
>> wrote:
>> >
>> > > No this is not open sourced yet..  As per the interest from the
>>HBase
>> > > community we can think of contributing..
>> > > It is time to see HBase community version with sec indexing in it
>> (IMHO)
>> > >  :)
>> > >
>> > > -Anoop-
>> > >
>> > > ________________________________________
>> > > From: Andrey Stepachev [[EMAIL PROTECTED]]
>> > > Sent: Wednesday, December 05, 2012 5:22 PM
>> > > To: [EMAIL PROTECTED]
>> > > Subject: Re: HBase - Secondary Index
>> > >
>> > > Hi.
>> > >
>> > > Indexing solution looks tempting.
>> > > Are there any plans to open source your solution (or it already open
>> and
>> > I
>> > > can't find it?).
>> > >
>> > >
>> > >
>> > >
>> > > On Tue, Dec 4, 2012 at 12:10 PM, Anoop Sam John <[EMAIL PROTECTED]>
>> > > wrote:
>> > >
>> > > > Hi All
>> > > >
>> > > >             Last week I got a chance to present the secondary
>> indexing
>> > > > solution what we have done in Huawei at the China Hadoop
>>Conference.
>> >  You