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From Stuart Smith <stu24m...@yahoo.com>
Subject Re: Questions on timestamps, insights on how timerange/timestamp filter are processed?
Date Wed, 14 Dec 2011 17:39:23 GMT
Hello Thomas,

   Someone here could probably provide more help, but to start you off, the only way I've
filtered timestamps is to do a scan, and just filter out rows one by one. This definitely
sounds like something coprocessors could help with, but I don't really understand those yet,
so someone else will have to step up.. or you can really dig into the documentation about
them (AFAIK, it's a little bit of custom code that runs on the regionservers that can pre-process
your gets.. but don't quote me on that!).

But I can say that a major compaction should not affect them - I've never seen it happen,
and if it does, I believe that's a bug.

Take care,
  -stu



________________________________
 From: Steinmaurer Thomas <Thomas.Steinmaurer@scch.at>
To: user@hbase.apache.org 
Sent: Wednesday, December 14, 2011 12:38 AM
Subject: Questions on timestamps, insights on how timerange/timestamp filter are processed?
 
Hello,

can anybody share some insights on how timerange/timestamp filters are
processed?

Basically we intend to use timerange/timestamp filters to process rather
new data from an insertion timestamp POV

- How does the process of skipping records and/or regions work, if one
use timerange filters?
- I also wonder, do timestamp change when e.g. running a major
compaction?
- If data grows over the years, is there any chance that regions with
"older" rows keep "stable" in a way, that they can be skipped very
quickly when querying data with a timerange filter of e.g. the last
three yours?

Thanks,
Thomas
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