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https://issues.apache.org/jira/browse/LUCENE-2205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13109834#comment-13109834
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Aaron McCurry commented on LUCENE-2205:
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Memory fragmentation aside, if an index segment contained 2.1 B terms and a
default term index interval of 128, each term would need to about 16M for the
byte[] to run out of space. However due to the growing array the likely hood
of it landing on 2.1 exactly is probably not likely. So it would probably
error out sometime before that.
I can back port PagedBytes instead if you think it's really needed.
I'm working on the PackedInts suggestion now, all the others have already been
corrected.
> Rework of the TermInfosReader class to remove the Terms[], TermInfos[], and
> the index pointer long[] and create a more memory efficient data structure.
> -------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: LUCENE-2205
> URL: https://issues.apache.org/jira/browse/LUCENE-2205
> Project: Lucene - Java
> Issue Type: Improvement
> Components: core/index
> Environment: Java5
> Reporter: Aaron McCurry
> Assignee: Michael McCandless
> Fix For: 3.5
>
> Attachments: RandomAccessTest.java, TermInfosReader.java,
> TermInfosReaderIndex.java, TermInfosReaderIndexDefault.java,
> TermInfosReaderIndexSmall.java, lowmemory_w_utf8_encoding.patch,
> patch-final.txt, rawoutput.txt
>
>
> Basically packing those three arrays into a byte array with an int array as
> an index offset.
> The performance benefits are stagering on my test index (of size 6.2 GB, with
> ~1,000,000 documents and ~175,000,000 terms), the memory needed to load the
> terminfos into memory were reduced to 17% of there original size. From 291.5
> MB to 49.7 MB. The random access speed has been made better by 1-2%, load
> time of the segments are ~40% faster as well, and full GC's on my JVM were
> made 7 times faster.
> I have already performed the work and am offering this code as a patch.
> Currently all test in the trunk pass with this new code enabled. I did write
> a system property switch to allow for the original implementation to be used
> as well.
> -Dorg.apache.lucene.index.TermInfosReader=default or small
> I have also written a blog about this patch here is the link.
> http://www.nearinfinity.com/blogs/aaron_mccurry/my_first_lucene_patch.html
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