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From Roshan Punnoose <rosh...@gmail.com>
Subject Re: Reverse Index Timestamp
Date Tue, 27 Nov 2012 17:21:39 GMT
The <string> would most likely be a fixed set of strings that do not change
over time.

My question is if it is bad to use a reverse index timestamp in the row id?
Will it cause problems with the tablet splitting, compaction, and
performance if the data is always being sent to the top of the tablet? If I
define a split as everything prefixed with <string>, then the ingest will
go to one tablet, but then I add a reverse timestamp in the row, and that
would mean I am always copying data to the top of the tablet. Will this
cause performance issues? Or is it better to append to a tablet?


On Tue, Nov 27, 2012 at 11:51 AM, Keith Turner <keith@deenlo.com> wrote:

>
>
> Keith
>
> On Tue, Nov 27, 2012 at 10:41 AM, Roshan Punnoose <roshanp@gmail.com>wrote:
>
>> I want to have a table where the row will consist of "<string>-<reverse
>> index timestamp>". But this means that the data is always being prefixed to
>> the beginning of the row (or tablet if the row is large). Will this be a
>> problem for compaction or performance?
>
>
> Can you tell me more about what <string> is?  For example is it a hash or
> does it come from the set "foo1","foo2","foo3".   How does it change over
> time?  I think the answer to your question depends on what <string> is.
>
>
>>
>> I don't know if I heard this correctly, but someone once mentioned that
>> making the row id the direct timestamp could cause performance issues
>> because data is always going to one tablet, but also because there is
>> trouble splitting since it always appends to the tablet. Is this true, is
>> it similar to what could happen if I am always prefixing to a tablet?
>>
>
> Yes using a timestamp for a row could cause data from many clients to
> always go to the same tablet, which would be bad for performance on a
> cluster.
>
>
>>
>> Thanks!
>> Roshan
>>
>
>

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