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From Brian Candler <B.Cand...@pobox.com>
Subject Re: Incremental map/reduce
Date Sat, 31 Jan 2009 21:56:51 GMT
On Sat, Jan 31, 2009 at 01:42:54PM -0800, Chris Anderson wrote:
> It's how it works today. The reason we see a small cost with each
> reduce query is that the intermediate reduction values are cached
> according to the btree structure, instead of according to the query
> params. So unless your range happens to match exactly the keys
> underneath a given inner node (and probably a this point even if it
> does) you'll end up running at least one javascript reduction per
> reduce query.

... and a group=true or group_level=N query basically generates a load of
individual group=false queries across different key ranges, so may take O(n)
in the number of groups returned.

I'm much happier about this now. Thank you!

Cheers,

Brian.

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