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From Federico Pici <>
Subject Re: About custom score using Solr8/Lucene8
Date Thu, 09 May 2019 11:57:39 GMT
Yes this was an option, and it solves a part of the problem.

But let’s consider this use case:

for each user index we need to calculate some important informations based on the most relevant
terms, the “starred” documents, the number of times the were opened by user (and other
key factors based on documents usage).
So, maybe weekly, we should update this “global” factors that would affect each user’s
document score. If this week i opened, for example, more documents of typeA and less of typeB,
ALL documents of typeA would be more important
of all documents of typeB (this is just a strategy). So each time i recalculate “global”
importance key factors i would need to update every user’s document to change its score.

In this case i would fear scaling up, because as users grow up (and as each user’s document
number grow up) i would been updating more and more document.

That’s why i would like to separate this moments. I would calculate “global” key factors
in a separate process, but i would like to use them at query time to generate different scoring

> Il giorno 9 mag 2019, alle ore 13:29, Diego Ceccarelli (BLOOMBERG/ LONDON) <>
ha scritto:
> why would you need to reindex all the users documents everynight? is the score affected
by the number of documents per user? 
> Also for scores, you might be able to use in-place updates: 
> so no need to reindex all the document. 
> From: At: 05/09/19 11:07:37To:  Diego Ceccarelli (BLOOMBERG/
> Subject: Re: About custom score using Solr8/Lucene8
> Well,
> my index is basically a list of documents of users. so i could say i got a 
> couple of millions of documents per user.
> I need to produce a score that is unrelated with search term (something like 
> “give me documents that are the most important to user”). I would 
> search for documents of a user without specifying a particular term. Documents 
> that are the most important for a user are calculated with strategy based 
> on particular text analysis (we still do not have a strategy).
> I evaluated the idea of storing a score for each document based on an external 
> scoring strategy (a job that reindex each user’s document every night?), but 
> i do not know how could scale up (more user with many documents could make this 
> strategy problematic in the long time), so the idea was to be able
> to calculate this scoring (or other scoring strategy) trying to follow some 
> best-practice (and as i can see using CustomScoreQuery is the most preferred 
> way)
> I was not able to try a solution because of Lucene8 missing CustomScoreQuery.
> I made something very basic using ValueSourceParser (but is this a good 
> practice?)
>> Il giorno 9 mag 2019, alle ore 10:50, Diego Ceccarelli (BLOOMBERG/ LONDON) 
> <> ha scritto:
>> Hi Federico, 
>> Could you give more details on what is the score that you want to produce? 
> how big is the collection? 
>> Is the score affected by the query? if not, would be possible to store the 
> score with the document? 
>> Cheers,
>> Diego
>> From: At: 05/09/19 08:13:35To:  
>> Subject: Re: About custom score using Solr8/Lucene8
>> Hello Mikhail,
>> yes i did. I read all the page at 
>> <>
>> I still do not understand where/how to start to write a class to be embedded 
> in 
>> solr8. All
>> available example since 2012 where written around 
>> CustomScoreQuery/CustomScoreProvider.
>> I really don’t know how to setup a minimal project to implement custom 
> scoring 
>> in solr8/lucene8 using FunctionScoreQuery
>>> Il giorno 8 mag 2019, alle ore 22:15, Mikhail Khludnev <>
>> scritto:
>>> Hello.
>>> Have you checked the fourth item at
>>> ?
>>> On Wed, May 8, 2019 at 5:46 PM Federico Pici <>
>>> wrote:
>>>> Hi,
>>>> i was trying to implement custom score inside my solr8 instance.
>>>> On google i found some examples, all focused on using CustomScoreProvider
>>>> and CustomScoreQuery classes. This classes have been removed in
>>>> Solr8/Lucene8
>>>> and, from Lucene 8 changeling, i saw a developer /contributor saying to
>>>> use FunctionScoreQuery.
>>>> Googling around was unsuccessful as i found no example, so i have no clue
>>>> from where to start from
>>>> I think i have a very basic need. Generate a score from field in
>>>> documents using logic completely unrelated with query itself.
>>>> The only way available (until any clue…) is using
>>>> Is there any example, at least to understand how to start a minimal basic
>>>> project?
>>>> Thanks
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>>> -- 
>>> Sincerely yours
>>> Mikhail Khludnev
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