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https://issues.apache.org/jira/browse/LUCENE-4225?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13415083#comment-13415083
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Michael McCandless commented on LUCENE-4225:
--------------------------------------------
Initial results are compelling! On the 10M doc Wikipedia test,
Sep(For) vs Fixed(For):
{noformat}
Task QPS base StdDev base QPS for StdDev for Pct
diff
IntNRQ 8.40 0.83 8.33 0.38 -13% -
15%
TermGroup1M 46.67 1.51 48.95 0.21 1% -
8%
TermBGroup1M 79.97 1.96 85.05 0.52 3% -
9%
Prefix3 68.82 2.62 73.96 2.27 0% -
15%
Fuzzy2 69.54 2.69 75.55 2.29 1% -
16%
TermBGroup1M1P 42.67 1.07 46.38 0.86 4% -
13%
Fuzzy1 85.07 3.34 93.16 2.20 2% -
16%
Respell 67.30 2.20 74.69 3.87 1% -
20%
Term 156.81 8.62 180.38 6.83 4% -
26%
Wildcard 42.55 1.13 50.97 0.87 14% -
25%
OrHighHigh 8.66 0.77 10.46 0.59 4% -
40%
OrHighMed 15.62 1.54 18.93 1.05 4% -
41%
AndHighMed 45.80 1.69 57.18 0.80 18% -
31%
SpanNear 7.59 0.32 9.95 0.14 23% -
38%
AndHighHigh 11.09 0.32 14.68 0.15 27% -
37%
PKLookup 143.83 2.80 195.40 4.13 30% -
41%
Phrase 15.53 1.15 21.34 0.18 26% -
49%
SloppyPhrase 5.94 0.49 8.74 0.24 32% -
64%
{noformat}
And Fixed(For) vs Lucene40:
{noformat}
Task QPS base StdDev base QPS for StdDev for Pct
diff
AndHighMed 60.07 1.69 44.20 1.17 -30% -
-22%
Phrase 11.97 0.60 9.61 0.20 -25% -
-13%
IntNRQ 9.77 0.46 8.93 0.38 -16% -
0%
Fuzzy2 49.08 1.33 48.72 1.08 -5% -
4%
Respell 61.33 1.52 60.90 1.41 -5% -
4%
SpanNear 7.72 0.20 7.74 0.07 -3% -
3%
PKLookup 194.64 3.03 197.83 3.27 -1% -
4%
SloppyPhrase 4.76 0.19 4.93 0.11 -2% -
10%
Fuzzy1 63.49 1.07 66.57 1.53 0% -
9%
TermGroup1M 53.91 1.40 58.24 1.27 3% -
13%
Prefix3 61.02 1.72 66.14 2.11 2% -
15%
Wildcard 51.27 1.40 56.26 1.78 3% -
16%
TermBGroup1M1P 29.65 0.98 32.77 0.79 4% -
17%
TermBGroup1M 34.37 1.16 38.07 1.14 3% -
18%
Term 24.98 1.32 28.13 3.31 -5% -
32%
AndHighHigh 17.08 0.69 19.42 0.52 6% -
21%
OrHighHigh 10.68 0.40 12.52 0.94 4% -
30%
OrHighMed 13.66 0.52 16.65 1.34 7% -
36%
{noformat}
So we are still slower than Lucene40 in some cases, but a lot closer
than with Sep!
But these are early results ... and the PF doesn't pass tests yet ... so!
> New FixedPostingsFormat for less overhead than SepPostingsFormat
> ----------------------------------------------------------------
>
> Key: LUCENE-4225
> URL: https://issues.apache.org/jira/browse/LUCENE-4225
> Project: Lucene - Java
> Issue Type: Bug
> Reporter: Michael McCandless
> Assignee: Michael McCandless
> Attachments: LUCENE-4225.patch
>
>
> I've worked out the start at a new postings format that should have
> less overhead for fixed-int[] encoders (For,PFor)... using ideas from
> the old bulk branch, and new ideas from Robert.
> It's only a start: there's no payloads support yet, and I haven't run
> Lucene's tests with it, except for one new test I added that tries to
> be a thorough PostingsFormat tester (to make it easier to create new
> postings formats). It does pass luceneutil's performance test, so
> it's at least able to run those queries correctly...
> Like Lucene40, it uses two files (though once we add payloads it may
> be 3). The .doc file interleaves doc delta and freq blocks, and .pos
> has position delta blocks. Unlike sep, blocks are NOT shared across
> terms; instead, it uses block encoding if there are enough ints to
> encode, else the same Lucene40 vInt format. This means low-freq terms
> (< 128 = current default block size) are always vInts, and high-freq
> terms will have some number of blocks, with a vInt final block.
> Skip points are only recorded at block starts.
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