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https://issues.apache.org/jira/browse/LUCENE-4069?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Mark Harwood updated LUCENE-4069:
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Attachment: BloomFilterPostingsBranch4x.patch
Updated as follows:
* Extracted Bloom filter functionality as new oal.util.FuzzySet class - the
name is changed because Bloom filtering is one application for a FuzzySet,
fuzzy count distincts being another.
* BloomFilterPostingsFormat now take a factory that can tailor choice of
BloomFilter per field (bitset size/saturation settings and choice of hash
algo). Provided a default factory implementation.
* All Unit tests pass now that I have a test PostingsFormat class that uses v
small bitsets where before the many-field unit tests would cause OOM.
Will follow up with benchmarks when I have more time to run and document them.
Initial results from my large-scale tests on growing indexes show a nice flat
line in the face of a growing index whereas a non-Bloomed index saw-tooths
upwards as segments grow/merge.
> Segment-level Bloom filters for a 2 x speed up on rare term searches
> --------------------------------------------------------------------
>
> Key: LUCENE-4069
> URL: https://issues.apache.org/jira/browse/LUCENE-4069
> Project: Lucene - Java
> Issue Type: Improvement
> Components: core/index
> Affects Versions: 3.6, 4.0
> Reporter: Mark Harwood
> Priority: Minor
> Fix For: 4.0, 3.6.1
>
> Attachments: BloomFilterPostingsBranch4x.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:
> http://www.slideshare.net/MarkHarwood/lucene-bloomfilteredsegments
> Benchmarks based on Wikipedia content here: http://goo.gl/X7QqU
> Patch based on 3.6 codebase attached.
> There are no 3.6 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.
> Also, a patch for Lucene4.0 codebase introducing a new PostingsFormat
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