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From "Michael McCandless (JIRA)" <>
Subject [jira] [Commented] (LUCENE-3932) Improve load time of .tii files
Date Tue, 22 May 2012 23:52:41 GMT


Michael McCandless commented on LUCENE-3932:

bq. Can this be ported to 3.6.1

I don't think so: it should only be bug fixes in 3.6.x series...

If we somehow did a 3.7 (which we're hoping not to: hopefully we get 4.0 alpha out instead)
then this could be backported for that...
> Improve load time of .tii files
> -------------------------------
>                 Key: LUCENE-3932
>                 URL:
>             Project: Lucene - Java
>          Issue Type: Improvement
>    Affects Versions: 3.5
>         Environment: Linux
>            Reporter: Sean Bridges
>            Assignee: Michael McCandless
>             Fix For: 4.0
>         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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