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From Andrew Purtell <apurt...@apache.org>
Subject Re: How to achieve secondary index consistency for concurrent scans and updates?
Date Mon, 28 Feb 2011 21:16:11 GMT
> For example there is topic table with time column (indexed).
> When new post is inserted, topic time column is updatet too (by delete
> index and reinsert new value?)
> So when table scan goes on it can miss record witch is updated
> (reinserted in already scaned values - am I right?).

Since HBase scanners don't support snapshot isolation, and won't, I think it is a non-goal
for secondary indexes also.
 
See hbase.apache.org/acid-semantics.html

"A scan is not a consistent view of a table. Scans do not exhibit snapshot isolation. Rather,
scans have the following properties: ..."

    - Andy

> From: piotrek69@gmail.com <piotrek69@gmail.com>
> Subject: How to achieve secondary index consistency for concurrent scans and updates?
> To: user@hbase.apache.org
> Date: Monday, February 28, 2011, 1:06 PM
> Hi, is possible to achieve secondary
> index consistency for concurrent
> scans and updates?
> 
> If I have data table with key UUID and index on time column
> then when I scan index by time there can be obsolete data (am |
> right?).
> 
> For example there is topic table with time column (indexed).
> When new post is inserted, topic time column is updatet too (by delete
> index and reinsert new value?)
> So when table scan goes on it can miss record witch is updated
> (reinserted in already scaned values - am I right?).
> 
> Is there any solution for this example use case?
> 
> Regards
> 


      

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