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From "Jack Krupansky" <j...@basetechnology.com>
Subject Re: Please Help solve problem of bad read performance in lucene 4.2.1
Date Sun, 07 Jul 2013 16:45:19 GMT
To be clear, Lucene and Solr are "search" engines, NOT "storage" engines. 
Has someone claimed otherwise to you?

What is your query performance in in 4.x vs. 3.x? That's the true, proper 
measure of Lucene and Solr performance.

-- Jack Krupansky

-----Original Message----- 
From: Chris Zhang
Sent: Sunday, July 07, 2013 12:26 PM
To: java-user@lucene.apache.org
Subject: Re: Please Help solve problem of bad read performance in lucene 
4.2.1

thianks Adrien,
In my project, almost all hit docs are supposed to be fetched for every
query, what's why I am upset by the poor reading performance. Maybe I
should store field values which are expected to be stored in high
performance storage engine.
In the above test case, time consuming of reading all docs in lucene 3.0 is
about 78 sec, that reading speed is approximately 10MB/s , but 700+ sec in
lucene 4.2.1, which indicates reading speed is less than 1MB/s.  So I think
committer of lucene should pay attention to this.


On Sun, Jul 7, 2013 at 10:23 PM, Adrien Grand <jpountz@gmail.com> wrote:

> Indeed, Lucene 4.1+ may be a bit slower for indices that comptelely
> fit in your file-system cache. On the other hand, you should see
> better performance with indices which are larger than the amount of
> physical memory of your machine. Your reading benchmark only measures
> IndexReader.get(int) which should only be used to display summary
> results (that is, only called 10 or 20 times per displayed page). Most
> of time, the bottleneck is rather searching which can be made more
> efficient on small indices by switching to an in-memory postings
> format.
>
> --
> Adrien
>
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