lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Michael McCandless (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (LUCENE-4283) Support more frequent skip with Block Postings Format
Date Sat, 04 Aug 2012 23:05:03 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-4283?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13428698#comment-13428698
] 

Michael McCandless commented on LUCENE-4283:
--------------------------------------------

I tested the -fully patch:
{noformat}
                Task    QPS base StdDev base    QPS comp StdDev comp      Pct diff
          AndHighLow      628.46        8.28      155.04        1.42  -75% -  -74%
         LowSpanNear        5.07        0.02        4.85        0.10   -6% -   -2%
         MedSpanNear        9.12        0.07        8.86        0.22   -5% -    0%
           OrHighMed       26.16        1.15       25.53        2.65  -16% -   12%
          AndHighMed       44.92        0.88       43.94        0.30   -4% -    0%
           OrHighLow       38.76        1.70       37.97        4.03  -16% -   13%
          OrHighHigh        9.57        0.45        9.40        1.02  -16% -   14%
            HighTerm       22.88        0.13       22.83        0.95   -4% -    4%
    HighSloppyPhrase        2.14        0.10        2.14        0.11   -9% -   10%
     LowSloppyPhrase        5.31        0.22        5.32        0.22   -7% -    8%
           LowPhrase        7.85        0.09        7.87        0.21   -3% -    3%
        HighSpanNear        1.65        0.01        1.66        0.04   -2% -    3%
             Respell       77.70        1.24       78.14        2.12   -3% -    4%
             MedTerm      138.26        0.52      139.07        5.52   -3% -    4%
            PKLookup      193.63        2.06      195.98        2.84   -1% -    3%
     MedSloppyPhrase       12.15        0.34       12.33        0.48   -5% -    8%
             LowTerm      525.12        4.89      534.89       14.12   -1% -    5%
              Fuzzy2       87.20        2.05       89.05        3.27   -3% -    8%
              Fuzzy1       97.81        2.33       99.94        3.99   -4% -    8%
         AndHighHigh       18.39        0.27       19.62        0.06    4% -    8%
           MedPhrase        5.09        0.11        5.52        0.33    0% -   17%
            Wildcard       67.59        0.58       73.76        3.37    3% -   15%
             Prefix3       25.51        0.39       29.54        1.60    7% -   23%
          HighPhrase        3.55        0.12        4.13        0.33    3% -   30%
              IntNRQ        8.79        0.08       10.67        1.52    3% -   40%
{noformat}

It seems like we are getting some gains for Med/HighPhrase, but AndHighLow is still way off.
                
> Support more frequent skip with Block Postings Format
> -----------------------------------------------------
>
>                 Key: LUCENE-4283
>                 URL: https://issues.apache.org/jira/browse/LUCENE-4283
>             Project: Lucene - Core
>          Issue Type: Improvement
>            Reporter: Han Jiang
>            Priority: Minor
>         Attachments: LUCENE-4283-buggy.patch, LUCENE-4283-buggy.patch, LUCENE-4283-slow.patch,
LUCENE-4283-small-interval-fully.patch, LUCENE-4283-small-interval-partially.patch
>
>
> This change works on the new bulk branch.
> Currently, our BlockPostingsFormat only supports skipInterval==blockSize. Every time
the skipper reaches the last level 0 skip point, we'll have to decode a whole block to read
doc/freq data. Also,  a higher level skip list will be created only for those df>blockSize^k,
which means for most terms, skipping will just be a linear scan. If we increase current blockSize
for better bulk i/o performance, current skip setting will be a bottleneck. 
> For ForPF, the encoded block can be easily splitted if we set skipInterval=32*k. 

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org


Mime
View raw message