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From David Boxenhorn <da...@citypath.com>
Subject Re: [SPAM] Re: slow insertion rate with secondary index
Date Mon, 06 Jun 2011 08:15:25 GMT
Is there really a 10x difference between indexed CFs and non-indexed CFs?

On Mon, Jun 6, 2011 at 11:05 AM, Donal Zang <zangds@ihep.ac.cn> wrote:

> On 06/06/2011 05:38, Jonathan Ellis wrote:
>
>> Index updates require read-before-write (to find out what the prior
>> version was, if any, and update the index accordingly).  This is
>> random i/o.
>>
>> Index creation on the other hand is a lot of sequential i/o, hence
>> more efficient.
>>
>> So, the classic bulk load advice to ingest data prior to creating
>> indexes applies.
>>
> Thanks for the explanation!
>
> --
> Donal Zang
> Computing Center, IHEP
> 19B YuquanLu, Shijingshan District,Beijing, 100049
> zangds@ihep.ac.cn
> 86 010 8823 6018
>
>
>

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