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Posted to user@accumulo.apache.org by Jamie Johnson <je...@gmail.com> on 2014/01/25 15:06:02 UTC
Key length limitations
I've read that in HBase there is a recommended limit on key lengths because
they're passed around quite a bit. Is the same true of accumulo? Are there
any recommendations in this regard?
Re: Key length limitations
Posted by Christopher <ct...@apache.org>.
Yes, I mean the row, column family, column qualifier (and also column
visibility).
I had intended "each", not "total", because 1K is probably too
constraining for some applications, but I don't think you'd see any
significant difference between the two, as they are on the same order
of magnitude.
--
Christopher L Tubbs II
http://gravatar.com/ctubbsii
On Sun, Jan 26, 2014 at 8:11 AM, Jamie Johnson <je...@gmail.com> wrote:
> Sorry for the basic question, but by key segment do you mean row key, column
> family column qualifier? So each should be less than a kilobyte or total?
> I think either way we are below that but I just want to make sure I
> understand the terminology. Again thanks for the reply.
>
>
> On Sun, Jan 26, 2014 at 2:12 AM, Christopher <ct...@apache.org> wrote:
>>
>> On the order of a kilobyte, or less, per key segment is probably
>> ideal. Beyond that, you may want to experiment to see what works for
>> you.
>>
>> Up to the order of a megabyte may work fine in newer versions (at
>> least 1.4), but I'd start having concerns about your schema decisions
>> after that, even if your performance was fine... since ultimately,
>> Accumulo tables are a sorted index, and I'd wonder what kind of index
>> needs such large keys.
>>
>> I suspect a few hundred bytes is probably plenty for most applications.
>>
>> --
>> Christopher L Tubbs II
>> http://gravatar.com/ctubbsii
>>
>>
>> On Sat, Jan 25, 2014 at 9:06 AM, Jamie Johnson <je...@gmail.com> wrote:
>> > I've read that in HBase there is a recommended limit on key lengths
>> > because
>> > they're passed around quite a bit. Is the same true of accumulo? Are
>> > there
>> > any recommendations in this regard?
>
>
Re: Key length limitations
Posted by Jamie Johnson <je...@gmail.com>.
Sorry for the basic question, but by key segment do you mean row key,
column family column qualifier? So each should be less than a kilobyte or
total? I think either way we are below that but I just want to make sure I
understand the terminology. Again thanks for the reply.
On Sun, Jan 26, 2014 at 2:12 AM, Christopher <ct...@apache.org> wrote:
> On the order of a kilobyte, or less, per key segment is probably
> ideal. Beyond that, you may want to experiment to see what works for
> you.
>
> Up to the order of a megabyte may work fine in newer versions (at
> least 1.4), but I'd start having concerns about your schema decisions
> after that, even if your performance was fine... since ultimately,
> Accumulo tables are a sorted index, and I'd wonder what kind of index
> needs such large keys.
>
> I suspect a few hundred bytes is probably plenty for most applications.
>
> --
> Christopher L Tubbs II
> http://gravatar.com/ctubbsii
>
>
> On Sat, Jan 25, 2014 at 9:06 AM, Jamie Johnson <je...@gmail.com> wrote:
> > I've read that in HBase there is a recommended limit on key lengths
> because
> > they're passed around quite a bit. Is the same true of accumulo? Are
> there
> > any recommendations in this regard?
>
Re: Key length limitations
Posted by Christopher <ct...@apache.org>.
On the order of a kilobyte, or less, per key segment is probably
ideal. Beyond that, you may want to experiment to see what works for
you.
Up to the order of a megabyte may work fine in newer versions (at
least 1.4), but I'd start having concerns about your schema decisions
after that, even if your performance was fine... since ultimately,
Accumulo tables are a sorted index, and I'd wonder what kind of index
needs such large keys.
I suspect a few hundred bytes is probably plenty for most applications.
--
Christopher L Tubbs II
http://gravatar.com/ctubbsii
On Sat, Jan 25, 2014 at 9:06 AM, Jamie Johnson <je...@gmail.com> wrote:
> I've read that in HBase there is a recommended limit on key lengths because
> they're passed around quite a bit. Is the same true of accumulo? Are there
> any recommendations in this regard?