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From PG <pengyunm...@gmail.com>
Subject Re: How HBase perform per-column scan?
Date Sun, 10 Mar 2013 14:14:51 GMT
Hi, Ted and Anoop, thanks for your notes.
I am talking about column rather than column family, since physically column family should
be able to perform efficiently (storage layer, CF's are stored separately). But columns of
the same column family may be mixed physically, and that makes filters column value hard...
So I want to know if there are any mechanism in HBase worked on this...

On Mar 10, 2013, at 10:01 AM, Ted Yu <yuzhihong@gmail.com> wrote:

> Hi, Yun:
> Take a look at HBASE-5416 (Improve performance of scans with some kind of
> filters) which is in 0.94.5 release.
> In your case, you can use a filter which specifies column C as the
> essential family.
> Here I interpret column C as column family.
> Cheers
> On Sat, Mar 9, 2013 at 11:11 AM, yun peng <pengyunmomo@gmail.com> wrote:
>> Hi, All,
>> I want to find all existing values for a given column in a HBase, and would
>> that result in a full-table scan in HBase? For example, given a column C,
>> the table is of very large number of rows, from which few rows (say only 1
>> row) have non-empty values for column C. Would HBase still ues a full table
>> scan to find this row? Or HBase has any optimization work for this kind of
>> query?
>> Thanks...
>> Regards
>> Yun

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