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From "Mark Harwood (JIRA)" <>
Subject [jira] [Updated] (LUCENE-4069) Segment-level Bloom filters for a 2 x speed up on rare term searches
Date Fri, 25 May 2012 15:13:23 GMT


Mark Harwood updated LUCENE-4069:

    Attachment: BloomFilterCodec40.patch

I've ported this Bloom Filtering code to work as a 4.0 Codec now.
I see a 35% improvement over standard Codecs on random lookups on a warmed index. 

I also notice that the PulsingCodec is no longer faster than standard Codec - is this news
to people as I thought it was supposed to be the way forward?

My test rig (adapted from Mike's original primary key test rig here
is attached as a zip.
The new BloomFilteringCodec is also attached here as a patch.

Searches against plain text fields also look to be faster (using AOL500k queries searching
Wikipedia English) but obviously that particular test rig is harder to include as an attachment

I can open a seperate JIRA issue for this 4.0 version of the code if that makes more sense.

> Segment-level Bloom filters for a 2 x speed up on rare term searches
> --------------------------------------------------------------------
>                 Key: LUCENE-4069
>                 URL:
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: core/index
>    Affects Versions: 3.6
>            Reporter: Mark Harwood
>            Priority: Minor
>             Fix For: 3.6.1
>         Attachments: BloomFilterCodec40.patch, MHBloomFilterOn3.6Branch.patch,
> An addition to each segment which stores a Bloom filter for selected fields in order
to give fast-fail to term searches, helping avoid wasted disk access.
> Best suited for low-frequency fields e.g. primary keys on big indexes with many segments
but also speeds up general searching in my tests.
> Overview slideshow here:
> Benchmarks based on Wikipedia content here:
> Patch based on 3.6 codebase attached.
> There are no API changes currently - to play just add a field with "_blm" on the end
of the name to invoke special indexing/querying capability. Clearly a new Field or schema
declaration(!) would need adding to APIs to configure the service properly.

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