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From Norman Barker <>
Subject Re: multiview using bloom filters
Date Sat, 25 Sep 2010 03:21:08 GMT

yes, performance is actually much better (for some of our harder
queries, so all docs over time with field X (two views), 10x faster),
I am testing with docs that in total emit ~100K of keys (following the
raindrop megaview).

Some of the scalable bloom filter project contained EPL headers,
others didn't, googling for the source code I had seen other projects
add the EPL headers to bit array so I did the same. I will contact the
author as he seems active on the erlang mailing lists and if not I
will write a bloom filter from scratch, the theory is well documented,
though I like his code!

thanks for your help, let me know any suggestions you may have.



On Fri, Sep 24, 2010 at 7:16 PM, Paul Davis <> wrote:
> Norman,
> Just glanced through. Looks better. Any feeling for a performance differences?
> Also, I glanced at the original files that you linked to. The bit
> array files didn't have a license, but what you've got there does have
> EPL headers. We need to make sure we have permission to do so. I would
> assume as much, but we have to be careful about such things in the
> ASF. You only need to get an email from the original author saying its
> ok.
> I'm a bit caught up with some other code at the moment, I'll give a
> more thorough combing over tomorrow.
> Paul
> On Fri, Sep 24, 2010 at 7:54 PM, Norman Barker <> wrote:
>> Hi,
>> thanks to Paul's excellent suggestion I have rewritten the multiview
>> to use bloom filters, I had a concern that a bloom filter per view
>> would use too much memory but thanks in the main to excellent
>> implementation of bloom filters in erlang
>> ( they seem to be
>> very space efficient.
>> New code is here
>> The code is simple, all one process, once we have agreed the approach
>> we can decide if there is any benefit in making the bloom filter
>> generation occur a separate process (using a genserver).
>> Comments as always appreciated, I will continue adding to the test suite.
>> thanks for the help,
>> Norman

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