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From "Paul Davis" <>
Subject Re: View performance
Date Wed, 07 Jan 2009 20:22:06 GMT
On Wed, Jan 7, 2009 at 8:44 AM, Chris Anderson <> wrote:
> On Wed, Jan 7, 2009 at 12:26 AM, George Palmer <> wrote:
>> Assuming I've used the view once so the index is built, am I just
>> paying the cost of looking up a userid as a key on an indexed data
>> set, so performance is really comparable to selecting 25 from 250,000
>> in a RDMS (with an index on a table)?
> Correct, once the index is built, the view lookups are fast.
>> Also how does performance scale as the number of items in a view
>> raises?  What if that was 100million items in the view that we had to
>> filter by userid?  Obviously we're looking to use a big data set here!
> The lookup cost should be O(log N), due to CouchDB's Btree indexes. So
> it should not slow down appreciable as the view index size grows.

Another note that this is a large base log. Btrees are specifically
designed to be shallow but very wide.

> --
> Chris Anderson

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