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From lars hofhansl <lhofha...@yahoo.com>
Subject Re: KeyValueScanner
Date Thu, 13 Sep 2012 05:38:34 GMT
reseek is forward only. So a scanner can potentially make use of that fact.
A seek can seek to any KV even if that means the scanner is rewound (so to speak) to a KV
that sorts before the current one.


For example see the implementations of seek(...) and reseek(...) in MemstoreScanner.


Is that what you were asking?


-- Lars



________________________________
 From: Matt Corgan <mcorgan@hotpads.com>
To: dev <dev@hbase.apache.org> 
Sent: Wednesday, September 12, 2012 10:25 PM
Subject: KeyValueScanner
 
Hi guys - I'm working on an interface for KeyValue and also trying to
figure out what changes we need to make to KeyValueScanner for prefix
compression.  One thing that's confusing me is the difference between the
seek() and reseek() methods.  Could someone take a stab at explaining those
since the javadoc is not of much help (kinda circular definition)?

I'd rather not even pollute this email with my best guess, but i think it
has something to do with reseek being used when you estimate you'll have to
seek many cells ahead, so you "zoom out" to the block index level (or
memstore root), whereas seek churns through every cell.

Any help appreciated,
Matt
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