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From Andrew Purtell <apurt...@apache.org>
Subject Re: on the impact of incremental counters
Date Mon, 20 Jun 2011 15:14:15 GMT
> From: Claudio Martella <claudio.martella@tis.bz.it>
> So, basically it's expensive to increment old data.

HBase employs a buffer hierarchy to make updating a working set that can fit in RAM reasonably
efficient. (But like I said there are some things remaining we can improve in terms of internal
data structure management.)

If you are updating a working set that does not fit in RAM or infrequently such that the value
is not maintained in cache, then HBase has to go to disk and we move from the order of memory
access to the order of disk access. 

It will obviously be more expensive to increment old data than newer, but I'm not sure I understand
what you are getting at. Any data management system with a buffer hierarchy has this behavior.

Compared to what?

   - Andy

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