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From "Sean Bridges (Issue Comment Edited) (JIRA)" <j...@apache.org>
Subject [jira] [Issue Comment Edited] (LUCENE-3932) Improve load time of .tii files
Date Mon, 02 Apr 2012 16:17:23 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-3932?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13244290#comment-13244290
] 

Sean Bridges edited comment on LUCENE-3932 at 4/2/12 4:16 PM:
--------------------------------------------------------------

{quote}I'm curious how much larger it'd be if we stopped delta coding... for your case, how
large is the byte[] in RAM (just call dataPagedBytes.getPointer(), just before we freeze it,
and print that result) vs the tii on disk...?{quote}

dataPagedBytes.getPointer() == 124973970

On disk the .tii file is 69508193 bytes

The entire index is ~50 gigs.
                
      was (Author: sgbridges):
    {quote}I'm curious how much larger it'd be if we stopped delta coding... for your case,
how large is the byte[] in RAM (just call dataPagedBytes.getPointer(), just before we freeze
it, and print that result) vs the tii on disk...?{quote}

dataPagedBytes.getPointer() == 124973970

On disk the .tii file is 69508193 bytes

                  
> Improve load time of .tii files
> -------------------------------
>
>                 Key: LUCENE-3932
>                 URL: https://issues.apache.org/jira/browse/LUCENE-3932
>             Project: Lucene - Java
>          Issue Type: Improvement
>    Affects Versions: 3.5
>         Environment: Linux
>            Reporter: Sean Bridges
>         Attachments: LUCENE-3932.trunk.patch, perf.csv
>
>
> We have a large 50 gig index which is optimized as one segment, with a 66 MEG .tii file.
 This index has no norms, and no field cache.
> It takes about 5 seconds to load this index, profiling reveals that 60% of the time is
spent in GrowableWriter.set(index, value), and most of time in set(...) is spent resizing
PackedInts.Mutatable current.
> In the constructor for TermInfosReaderIndex, you initialize the writer with the line,
> {quote}GrowableWriter indexToTerms = new GrowableWriter(4, indexSize, false);{quote}
> For our index using four as the bit estimate results in 27 resizes.
> The last value in indexToTerms is going to be ~ tiiFileLength, and if instead you use,
> {quote}int bitEstimate = (int) Math.ceil(Math.log10(tiiFileLength) / Math.log10(2));
> GrowableWriter indexToTerms = new GrowableWriter(bitEstimate, indexSize, false);{quote}
> Load time improves to ~ 2 seconds.

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