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From Fabio Forno <>
Subject key entropy and view performance
Date Mon, 22 Feb 2010 11:00:23 GMT
during view generation I've noticed that view re-indexing speed seems
very related to the entropy of keys. For example I've map/reduce view
which counts the a set of resources with a score and a type. The score
has a very high entropy (few tens of resources for each score), while
the resource type is limited (>100k per type). If I emit keys as
[type, score] map/reduce computation seems much slower than [score,
type]. Is it normal or a just a case? Isn't there the risk of
degeneration if the numbers of resources grows too much (eg. millions
per resource type)?
Since I need to do range queries according the score, but only on
selected types of resources, I think that the [type, score] key is
preferable, however this degradation in speed concerns me. Any hint?
thanks in advance.

Fabio Forno,
Bluendo srl
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