lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Michael McCandless (JIRA)" <>
Subject [jira] Commented: (LUCENE-2903) Improvement of PForDelta Codec
Date Thu, 03 Feb 2011 23:08:29 GMT


Michael McCandless commented on LUCENE-2903:

Hmm the last patch still seems to have disabled the allOnes opto in BulkVInt?  (I turned it
back on in my checkout).

Also it seems to have an added dep to Kamikaze, but it's not in fact needed?

I ran perf test on 10M Wikipedia docs, of BulkVInt vs PatcheFrameOfRef3, on Linux:

||Query||QPS bulkvint||QPS pfor3||Pct diff||||
|+nebraska +states|104.70|66.87|{color:red}-36.1%{color}|
|"united states"|12.19|9.05|{color:red}-25.7%{color}|
|united states|16.56|13.46|{color:red}-18.7%{color}|
|spanNear([unit, state], 10, true)|43.37|35.84|{color:red}-17.4%{color}|
|+united +states|19.51|16.27|{color:red}-16.6%{color}|
|spanFirst(unit, 5)|157.25|145.20|{color:red}-7.7%{color}|
|"united states"~3|5.80|5.37|{color:red}-7.4%{color}|
|doctimesecnum:[10000 TO 60000]|12.40|11.68|{color:red}-5.8%{color}|

Somehow it's substantially slower... but I haven't tested how the other PFor impl we have
compares.  Not sure what's up...

> Improvement of PForDelta Codec
> ------------------------------
>                 Key: LUCENE-2903
>                 URL:
>             Project: Lucene - Java
>          Issue Type: Improvement
>            Reporter: hao yan
>         Attachments: LUCENE_2903.patch, LUCENE_2903.patch
> There are 3 versions of PForDelta implementations in the Bulk Branch: FrameOfRef, PatchedFrameOfRef,
and PatchedFrameOfRef2.
> The FrameOfRef is a very basic one which is essentially a binary encoding (may result
in huge index size).
> The PatchedFrameOfRef is the implmentation based on the original version of PForDelta
in the literatures.
> The PatchedFrameOfRef2 is my previous implementation which are improved this time. (The
Codec name is changed to NewPForDelta.).
> In particular, the changes are:
> 1. I fixed the bug of my previous version (in Lucene-1410.patch), where the old PForDelta
does not support very large exceptions (since
> the Simple16 does not support very large numbers). Now this has been fixed in the new
> 2. I changed the PForDeltaFixedIntBlockCodec. Now it is faster than the other two PForDelta
implementation in the bulk branch (FrameOfRef and PatchedFrameOfRef). The codec's name is
"NewPForDelta", as you can see in the CodecProvider and PForDeltaFixedIntBlockCodec.
> 3. The performance test results are:
> 1) My "NewPForDelta" codec is faster then FrameOfRef and PatchedFrameOfRef for almost
all kinds of queries, slightly worse then BulkVInt.
> 2) My "NewPForDelta" codec can result in the smallest index size among all 4 methods,
including FrameOfRef, PatchedFrameOfRef, and BulkVInt, and itself)
> 3) All performance test results are achieved by running with "-server" instead of "-client"

This message is automatically generated by JIRA.
For more information on JIRA, see:


To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message