[
https://issues.apache.org/jira/browse/LUCENE-4864?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13609573#comment-13609573
]
Michael McCandless commented on LUCENE-4864:
--------------------------------------------
I ran a perf test with the full (wikimediumall) Wiki index, base = MMapDir,
comp = AsyncFSDir:
{noformat}
Task QPS base StdDev QPS comp StdDev
Pct diff
AndHighLow 567.56 (0.8%) 69.48 (0.1%)
-87.8% ( -87% - -87%)
Respell 42.45 (4.0%) 5.70 (0.2%)
-86.6% ( -87% - -85%)
LowPhrase 23.23 (1.4%) 3.34 (0.1%)
-85.6% ( -85% - -85%)
Fuzzy2 54.01 (5.1%) 8.60 (0.1%)
-84.1% ( -84% - -83%)
Fuzzy1 51.34 (4.3%) 9.47 (0.2%)
-81.6% ( -82% - -80%)
LowSloppyPhrase 24.87 (1.0%) 5.28 (0.0%)
-78.7% ( -79% - -78%)
AndHighMed 78.75 (0.5%) 19.49 (0.3%)
-75.2% ( -75% - -74%)
Wildcard 26.69 (2.7%) 7.97 (0.3%)
-70.1% ( -71% - -69%)
HighPhrase 12.71 (7.2%) 3.98 (1.0%)
-68.6% ( -71% - -65%)
MedPhrase 138.73 (6.5%) 51.65 (1.3%)
-62.8% ( -66% - -58%)
LowSpanNear 8.73 (1.6%) 3.28 (0.6%)
-62.5% ( -63% - -61%)
MedSloppyPhrase 27.76 (1.1%) 11.54 (0.3%)
-58.4% ( -59% - -57%)
MedTerm 64.12 (16.2%) 28.16 (3.2%)
-56.1% ( -64% - -43%)
AndHighHigh 19.39 (0.4%) 8.78 (0.3%)
-54.7% ( -55% - -54%)
HighTerm 51.06 (16.8%) 23.16 (4.6%)
-54.6% ( -65% - -39%)
OrHighMed 28.74 (0.4%) 14.31 (0.6%)
-50.2% ( -51% - -49%)
OrHighLow 27.15 (0.2%) 13.69 (0.9%)
-49.6% ( -50% - -48%)
OrHighHigh 16.17 (0.2%) 8.25 (0.8%)
-49.0% ( -49% - -48%)
HighSpanNear 3.28 (0.6%) 1.68 (0.6%)
-48.7% ( -49% - -47%)
MedSpanNear 29.58 (0.5%) 15.59 (0.8%)
-47.3% ( -48% - -46%)
HighSloppyPhrase 0.78 (3.2%) 0.42 (0.3%)
-46.3% ( -48% - -44%)
IntNRQ 3.35 (2.8%) 1.80 (1.0%)
-46.2% ( -48% - -43%)
Prefix3 18.97 (2.6%) 10.45 (1.1%)
-44.9% ( -47% - -42%)
LowTerm 312.34 (9.0%) 182.24 (2.8%)
-41.7% ( -49% - -32%)
{noformat}
I think the Future/wait is just too costly ...
> Add AsyncFSDirectory to work around Windows issues with NIOFS (Lucene 5.0
> only)
> -------------------------------------------------------------------------------
>
> Key: LUCENE-4864
> URL: https://issues.apache.org/jira/browse/LUCENE-4864
> Project: Lucene - Core
> Issue Type: Improvement
> Components: core/store
> Affects Versions: 5.0
> Reporter: Michael Poindexter
> Attachments: LUCENE-4864.patch, LUCENE-4864.patch
>
>
> On LUCENE-4848 a new directory implementation was proposed that uses
> AsyncFileChannel to make a sync-less directory implementation (only needed
> for IndexInput). The problem on Windows is that positional reads are
> impossible without overlapping (async) I/O, so FileChannel in the JDK has to
> syncronize all reads, because they consist of an atomic seek and atomic read.
> AsyncFSDirectoty would not have this issue, but has to take care of thread
> management, because you need a separate thread to get notified when the read
> is done. This involves overhead, but might still be better than the
> synchronization.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
