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https://issues.apache.org/jira/browse/LUCENE-1410?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12974303#action_12974303
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Paul Elschot commented on LUCENE-1410:
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bq. ... is it possible to encode # of exception bytes in header?
In the first implementation the start index of the exception chain is in the
header (5 or 6 bits iirc). In the second implementation (by Hoa Yan) there is
no exception chain, so the number of exceptions must somehow be encoded in the
header.
That means encoding the # exception bytes in the header would be easier in the
second implementation, but it is also possible in the first one.
I would expect that a few bits for the number of encoded integers would also be
added in the header (think 32, 64, 128...).
The number of frame bits takes 5 bits.
That means that there are about 2 bytes unused in the header now, and I'd
expect 1 byte to be enough to encode the number of bytes for the exceptions.
For example a bad case in the first implementation of 10 exceptions of 4 bytes
means 40 bytes data, that fits in 6 bits, the same
bad case in the second implementation would also need to store the indexes of
the exceptions in 10*5 bits, totalling 90 bytes that can be
encoded in 7 bits. However, I don't know what the worst case # exceptions is.
(This gets into vsencoding...)
For the moment I'll just leave this unchanged and get the tests working on the
current first implementation.
> PFOR implementation
> -------------------
>
> Key: LUCENE-1410
> URL: https://issues.apache.org/jira/browse/LUCENE-1410
> Project: Lucene - Java
> Issue Type: New Feature
> Components: Index
> Reporter: Paul Elschot
> Priority: Minor
> Fix For: Bulk Postings branch
>
> Attachments: autogen.tgz, for-summary.txt,
> LUCENE-1410-codecs.tar.bz2, LUCENE-1410.patch, LUCENE-1410.patch,
> LUCENE-1410.patch, LUCENE-1410.patch, LUCENE-1410b.patch, LUCENE-1410c.patch,
> LUCENE-1410d.patch, LUCENE-1410e.patch, TermQueryTests.tgz, TestPFor2.java,
> TestPFor2.java, TestPFor2.java
>
> Original Estimate: 21840h
> Remaining Estimate: 21840h
>
> Implementation of Patched Frame of Reference.
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