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https://issues.apache.org/jira/browse/LUCENE-1799?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Robert Muir updated LUCENE-1799:
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Attachment: LUCENE-1799.patch
attached is a patch for the start of a "BOCUUtil' with unicodeutil like methods.
For now i only implemented encode (and encodeWithHash):
I generated random strings with _TestUtil.randomRealisticUnicodeString and
benchmarked, and the numbers are stable.
||encoding||time to encode 20 million strings (ms)||number of encoded bytes||
|UTF-8|1,757|596,516,000|
|BOCU-1|1,968|250,202,000|
So I think we get good compression, and good performance close to UTF-8 for
encode.
I'll work on decode now.
> Unicode compression
> -------------------
>
> Key: LUCENE-1799
> URL: https://issues.apache.org/jira/browse/LUCENE-1799
> Project: Lucene - Java
> Issue Type: New Feature
> Components: Store
> Affects Versions: 2.4.1
> Reporter: DM Smith
> Priority: Minor
> Attachments: LUCENE-1799.patch, LUCENE-1799.patch, LUCENE-1799.patch,
> LUCENE-1799.patch, LUCENE-1799.patch, LUCENE-1799.patch, LUCENE-1799.patch,
> LUCENE-1799_big.patch
>
>
> In lucene-1793, there is the off-topic suggestion to provide compression of
> Unicode data. The motivation was a custom encoding in a Russian analyzer. The
> original supposition was that it provided a more compact index.
> This led to the comment that a different or compressed encoding would be a
> generally useful feature.
> BOCU-1 was suggested as a possibility. This is a patented algorithm by IBM
> with an implementation in ICU. If Lucene provide it's own implementation a
> freely avIlable, royalty-free license would need to be obtained.
> SCSU is another Unicode compression algorithm that could be used.
> An advantage of these methods is that they work on the whole of Unicode. If
> that is not needed an encoding such as iso8859-1 (or whatever covers the
> input) could be used.
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