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From Jack Park <>
Subject Re: Flow Chart of Solr
Date Wed, 03 Apr 2013 15:25:13 GMT
There are three books on Solr, two with that in the title, and one,
Taming Text, each of which have been very valuable in understanding


On Wed, Apr 3, 2013 at 5:25 AM, Jack Krupansky <> wrote:
> Sure, yes. But... it comes down to what level of detail you want and need
> for a specific task. In other words, there are probably a dozen or more
> levels of detail. The reality is that if you are going to work at the Solr
> code level, that is very, very different than being a "user" of Solr, and at
> that point your first step is to become familiar with the code itself.
> When you talk about "parsing" and "stemming", you are really talking about
> the user-level, not the Solr code level. Maybe what you really need is a
> cheat sheet that maps a user-visible feature to the main Solr code component
> for that implements that user feature.
> There are a number of different forms of "parsing" in Solr - parsing of
> what? Queries? Requests? Solr documents? Function queries?
> Stemming? Well, in truth, Solr doesn't even do stemming - Lucene does that.
> Lucene does all of the "token filtering". Are you asking for details on how
> Lucene works? Maybe you meant to ask how "term analysis" works, which is
> split between Solr and Lucene. Or maybe you simply wanted to know when and
> where term analysis is done. Tell us your specific problem or specific
> question and we can probably quickly give you an answer.
> In truth, NOBODY uses "flow charts" anymore. Sure, there are some user-level
> diagrams, but not down to the code level.
> If you could focus on specific questions, we could give you specific
> answers.
> "Main steps"? That depends on what level you are working at. Tell us what
> problem you are trying to solve and we can point you to the relevant areas.
> In truth, if you become generally familiar with Solr at the user level
> (study the wikis), you will already know what the "main steps" are.
> So, it is not "main steps of Solr", but main steps of some specific
> "request" of Solr, and for a specified level of detail, and for a specified
> area of Solr if greater detail is needed. Be more specific, and then we can
> be more specific.
> For now, the general advice for people who need or want to go far beyond the
> user level is to "get familiar with the code" - just LOOK at it - a lot of
> the package and class names are OBVIOUS, really, and follow the class
> hierarchy and code flow using the standard features of any modern Java IDE.
> If you are wondering where to start for some specific user-level feature,
> please ask specifically about that feature. But... make a diligent effort to
> discover and learn on your own before asking open-ended questions.
> Sure, there are lots of things in Lucene and Solr that are rather complex
> and seemingly convoluted, and not obvious, but people are more than willing
> to help you out if you simply ask a specific question. I mean, not everybody
> needs to know the fine detail of query parsing, analysis, building a
> Lucene-level stemmer, etc. If we tried to put all of that in a diagram, most
> people would be more confused than enlightened.
> At which step are scores calculated? That's more of a Lucene question. Or,
> are you really asking what code in Solr invokes Lucene search methods that
> calculate basic scores?
> In short, you need to be more specific. Don't force us to guess what problem
> you are trying to solve.
> -- Jack Krupansky
> -----Original Message----- From: Furkan KAMACI
> Sent: Wednesday, April 03, 2013 6:52 AM
> To:
> Subject: Re: Flow Chart of Solr
> So, all in all, is there anybody who can write down just main steps of
> Solr(including parsing, stemming etc.)?
> 2013/4/2 Furkan KAMACI <>
>> I think about myself as an example. I have started to make research about
>> Solr just for some weeks. I have learned Solr and its related projects. My
>> next step writing down the main steps Solr. We have separated learning
>> curve of Solr into two main categories.
>> First one is who are using it as out of the box components. Second one is
>> developer side.
>> Actually developer side branches into two way.
>> First one is general steps of it. i.e. document comes into Solr (i.e.
>> crawled data of Nutch). which analyzing processes are going to done
>> (stamming, hamming etc.), what will be doing after parsing step by step.
>> When a search query happens what happens step by step, at which step
>> scores
>> are calculated so on so forth.
>> Second one is more code specific i.e. which handlers takes into account
>> data that will going to be indexed(no need the explain every handler at
>> this step) . Which are the analyzer, tokenizer classes and what are the
>> flow between them. How response handlers works and what are they.
>> Also explaining about cloud side is other work.
>> Some of explanations are currently presents at wiki (but some of them are
>> at very deep places at wiki and it is not easy to find the parent topic of
>> it, maybe starting wiki from a top age and branching all other topics as
>> possible as from it could be better)
>> If we could show the big picture, and beside of it the smaller pictures
>> within it, it would be great (if you know the main parts it will be easy
>> to
>> go deep into the code i.e. you don't need to explain every handler, if you
>> show the way to the developer he/she could debug and find the needs)
>> When I think about myself as an example, I have to write down the steps of
>> Solr a bit detail  even I read many pages at wiki and a book about it, I
>> see that it is not easy even writing down the big picture of developer
>> side.
>> 2013/4/2 Alexandre Rafalovitch <>
>>> Yago,
>>> My point - perhaps lost in too much text - was that Solr is presented -
>>> and
>>> can function - as a black-box. Which makes it different from more
>>> traditional open-source project. So, the stage-2 happens exactly when the
>>> non-programmers have to cross the boundary from the black-box into
>>> code-first approach and the hand-off is not particularly smooth. Or even
>>> when - say - php or .Net programmer  tries to get beyond the basic
>>> operations their client library and has the understand the server-side
>>> aspects of Solr.
>>> Regards,
>>>    Alex.
>>> On Tue, Apr 2, 2013 at 1:19 PM, Yago Riveiro <>
>>> wrote:
>>> > Alexandre,
>>> >
>>> > You describe the normal path when a beginner try to use a source of >
>>> > code
>>> > that doesn't understand, black-box, reading code, hacking, ok now I >
>>> > know
>>> > 10% of the project, with lucky :p.
>>> >
>>> Personal blog:
>>> LinkedIn:
>>> - Time is the quality of nature that keeps events from happening all at
>>> once. Lately, it doesn't seem to be working.  (Anonymous  - via GTD book)

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