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From "Gabriel Reid (JIRA)" <>
Subject [jira] [Commented] (CRUNCH-215) Add BloomFilterJoinStrategy
Date Mon, 10 Jun 2013 07:03:22 GMT


Gabriel Reid commented on CRUNCH-215:

Thanks for looking at it Josh.

As for #1, yeah, I was banging my head on that for quite a while. I tried writing some integration
tests to replicate what I was running into, but I wasn't able to get the same problem. My
best guess is that this is specifically an issue with the integration tests and the shape
of the pipeline that is used there, although I didn't check that specifically.

For #2, that was actually what I had in mind at first, but then it felt like it was too specific
to this one use case -- are there any other use cases where we want to have a toBytes method?
> Add BloomFilterJoinStrategy
> ---------------------------
>                 Key: CRUNCH-215
>                 URL:
>             Project: Crunch
>          Issue Type: New Feature
>            Reporter: Gabriel Reid
>            Assignee: Gabriel Reid
>         Attachments: CRUNCH-215.patch
> Bloom filters can be very effective for pre-filtering one side of a join when one side
of the join has a small subset of the keys of the other side (i.e. there are many keys on
one side that will not be joined).
> The Bloom filter can be built up based on the keys of one side of the join (the side
with fewer keys), and then can be applied as a filter to the other side of the join before
it is sent through the shuffle and reduce phases.

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