[Xapian-discuss] questions about xapian

[白俊良]

> Date: Thu, 16 Apr 2009 02:55:16 +0100
> From: olly at survex.com
> To: baijl03 at hotmail.com
> CC: xapian-discuss at lists.xapian.org
> Subject: Re: [Xapian-discuss] questions about xapian
> 

I am very sorry to do that, since I did not know which one my questions would be approprate better. 
> Please don't post the same message to both xapian-discuss and xapian-devel.
> Pick whichever is most appropriate for your message and use that.
> 
> On Wed, Apr 15, 2009 at 10:46:47AM +0800, ???×? wrote:
> > i have read code of xapian more than one month,i leant a lot from your code
> > both form design of search engine and code details.
> > however, something make me in a puzzle. 
> > Take RefCntBase as an example, it seems that it is a "kernel" of xapian, as
> > many classes inherit from it. But,what is it funtion? why is it so important?
> 
> It's just an implementation detail - don't worry about it if you are
> only wanting to use the API.
> 
> (If you're wanting to understand how Xapian works, it's a base class for
> objects which we want to reference count).
> 

Indeed, I care more about how Xapian works.And I want to learn how  search 

engine works and how to design or  optimize a search engine.

I realized that it is a basic and important class since many classes inherit from it.

So, why Xapian needs reference count ?

Or is it a basic requirement of OOP or search engine programming?
> > Another confusion is about Valuerangeprocess. I really want to make clear 
> > differences between valuerange-search and common search in details. I added 
> > Xapian::DateValueRangeProcessor date_proc(2, true, 1930); 
> > qp.add_valuerangeprocessor(&date_proc); 
> > in my code and my code works well. then, I debug it using gdb.
> > however,i can not be inspired. Is there any important information i
> > did not catch?
> 
> Did you read this:
> 
> http://xapian.org/docs/valueranges.html
> 
> Otherwise, please ask about the specifics of what you want to know.
> It's much harder to answer such general questions.
> 

Generally speaking,i want to now how "valuerangesearch" works. Whether it only 

search in field "Value" or not? What the differences are between "valuerangesearch" 

and common search,which parse query into terms and retrieval terms in db ?

 

I did read this document a few days ago.and i can using "valuerangesearch" now.

However,I can not make clear that how the match run with "valuerangeprocessor".

I have also read  this:

http://xapian.org/docs/matcherdesign.html

I can not find "ValueRangePostList" or "RangeFilter",which make me confused.

Then, how the PostList Tree was design with RangeProcessor?

 

Thanks a lot !
> Cheers,
> Olly


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