29 Nov
2012
29 Nov
'12
3:47 p.m.
Hi,
On Wed, Nov 28, 2012 at 5:35 PM, Ludovic Dubost <ludovic(a)xwiki.com> wrote:
Sure. I was just repeating what is important.
"French" but look in the "French" + "English" dataset. For
me if both
documents with the same page name match, both should come out separately.
It's the same as in the UI allows you to specify which language to search
in, but it also allows you to specify that you want to search in "All
languages", that is what I meant.
Not specifically as an API
I understand now what you mean. Well, to avoid this, we can use only one
notion and that is the one of "supported languages". All the supported
languages should be indexed in order for the Search feature to work as
expected (and not have the case where you have a document that is not
indexed because of its language). I am not sure if there are many examples
where admins would choose to index just some of the supported languages and
not index all of them.
WDYT?
ALL
What I think you are actually asking is that all languages are queried, but
that results in the requested language get boosted/elevated and thus are
displayed before all other language results.
Perhaps this can be achieved by using the lang field as a query field and
not as a query filter. This means that it will influence the score. Couple
that with a higher boost for the lang field and results in the requested
language should be scored better than all the rest (because there will
always be a hit for the lang field resulting in a better score). There
might still be some results from other languages that could have a better
score than results from the requested language (because they just have more
hits on diferent fields), but it should work in most cases.
However, I`m not sure we want this. Users might results from other
languages as a bug. Problems might also be harder to debug.
Instead, we could do something like Google and if we see a small number of
results, we could suggest that the user searches in all languages.
In any case, I`m not sure this is such a big issue right now, since it's
basically an optimisation that we could choose to do, or let the user do it
himself, since he has the tools (UI).
I agree. The one-document-for-all-languages solution was proposed by Paul,
but I don`t think it's the way to go. We are currently only considering the
one-document-per-language direction.
"objcontent" stores the properties (format: "propName:propValue") of
each
object inside the original document (multi-valued field).
Besides XWikiDocuments, we also index Objects, Properties and Attachments
as Lucene/Solr first-class documents. Each of these entries has the wiki,
space, name and lang fields set from the document to which they belong to.
This is what I meant above with "if we search for the
object/property/attachment itself"
So to reiterate, the idea was that if you want to search for an indexed
Object (type:"OBJECT"), you will *have* to avoid setting a language filter,
or you might not find the object you are looking for, since it is indexed
under the language of original document.
---
While writing this down, I just thought of an elegant idea to fix this. The
lang field could be set to multi-valued. This means that, when we index
objects, properties and attachments, we could set in the lang field all the
values corresponding to all the existing translations of the owning
document. Example:
An Object:
id: xwiki:Main.Page^XWiki.Class[0] <-- (object reference)
class: XWiki.Class
wiki: xwiki
space: Main
name: Page
lang: en <-- proposal to make it multi-valued would look like this,
stored like a list of values.
fr
de
type: OBJECT
Note that this solution would also affect document languages as well (since
they share the same schema), but we will just put one value and it will not
affect queries. Queries will still be written like: "lang:en"
If we apply this solution, even if a language filter exists in the user's
query, it will still hit the object because the lang field of the object
contains the value.
2012/11/28 Eduard Moraru <enygma2002(a)gmail.com>
Why/How can you end up with documents of other languages than the current
default one if the wiki is mono-lingual?
Hi Ludovic,
Thanks for the reply. Please read below...
On Tue, Nov 27, 2012 at 5:44 PM, Ludovic Dubost <ludovic(a)xwiki.com>
wrote:
> Hi Edy,
>
> I'm not a huge fan of the title_fr title_en title_morelanguages
approach
as
pollute
indeed it seems to be quite complex at the query
level. I was more
leaning
towards multiple indexes if we can query them
globally but I understand
this is complex too.
Now let's see the use cases that are hugely important:
1/ Make sure that if you decide your wiki is monolingual:
- the indexing uses the specific language analyzer
- make sure the query uses the specific language analyzer
- make sure the search looks in all content even if the language
setting
of the document is wrongly set (consider all
documents being of the
specific language)
You mean that, if the wiki is monolingual, we should ignore the language
filter and hardcode it to "All languages", right?
However, what would be the advantage of this? Why would be want to the results with irrelevant documents (caused by
a probable recent
configuration change that went from multi-lingual to mono-lignual)?
Wasn't
that the whole reason why the admin switched to
mono-lingual?
If the user is monolingual, we can safely ignore the language setting of
each document and only the "main" document will be shown anyway to the
user.
So we should make sure we search on ALL documents that are available to the
user.
The user might have to "reindex" to make sure this is properly taken into
account by the search engine.
What is important here, is that even if the wiki is set to "fr", then even
if documents have "en" for the main language they will still show up in the
search. The opposite would be bad.
2/ Allow is a wiki is multi-lingual:
- search in the language you decide (maybe the UI should display a
language choice for the query)
We already support this, by using the "Filtered Search" option and
selecting the language.
- search in content that is analyzed in the proper language when the
> content is declared in this language
> - allow to specify if you want to restrict your search to documents
> declared in the language of your query, versus search more widely in
all
documents
accross languages. If you search in only the language of the
query only one document can show up but it should point to the right
translation that matches, if you search in multiple languages then you
can
show individual translations.
I think this one is the same as the first bullet above.
No I think it's different. The user can decide to make his search in - allow technical users to search for all
documents across all
languages
(where the language analysis does not really
matter)
Do you mean as an API?
What exactly do you mean by "language analysis does not really matter"?
Any
Example?
I mean here that as a technical user your objective is to make sure your
search spans ALL content in the wiki. In this case you don't care about
stemming and such.
The standard UI could take this into account by choosing "any language
search" and with data set "all languages". We just need to make sure that
this won't exclude any content of the search
(Here is an example of a case where such exclusion might occur. Suppose you
have done only "French" and "English" indexing and there is
"German"
content also in your wiki but since you have not asked for German search in
your wiki you don't have title_de and content_de fields or don't have a
german specific solr index (in the other method), then your german content
would not be indexed at all ?)
>
> From an admin point of view it makes good sense for the admin to be
able
to
engine.
specify in a multilingual wiki which language
analysis should be
activated,
> and then have this transmitted to SOLR to properly configure the > Reindexing is ok when changing the
configuration.
>
> I believe in the end wether you use multiple fields with _fr _en or
> multiple SOLR cores, as long as you can query accross SOLR cores is a
bit
the same.
If you cannot run a query merging multiple indexes then the
first
> solution is kind of absolutely necessary as it would be the only one
> allowing to search across all languages.
>
> Maybe a solution would be to create one index per language and index > content regardless of it's language
using the language analyzer of that
> index. This would allow to have better results even though the users
have
> badly tagged the language of a document, and
it's only the job of the
UI
to
all
limit the search to only the language of the
query, or all documents.
So you could have a configuration in the admin
that says:
1/ Create an English Index
2/ Create an additional French index
The UI would allow to search in English and French, + would add a
language
restriction for the documents.
Applying the language specific analyzers (for Chinese, for example) to the documents will just create a mess for all the
documents that do not
match the analyzer's language. I`m not sure the results for the
badly-indexed languages will make any sense to users.
I undestand the issue here, but in most cases the user will say "french
search" on "french content", he will only expand to non french content if
he was not satisfied by his search. What is just allowed here is to also
search in "french" inside all content. That would cover content that would
have the bad language setting as well as any other content. The results
might be a bit noisy but I don't think it's a big issue.
Also, this is very similar to the multi-core
approach (one core per
language), just that you also add documents that are indexed with the
wrong
analyzers. We have the same problem regarding
merging relevance scores
across indexes (cores) that is a big turn-off for the original multi-core
approach.
This is a more serious issue. If it's hard to merge the results spanning
over
multiple cores this could be a showstopper. However the solution of
having only one Lucene document for all languages is not so cool either as
it would make it difficult to know which ones of the languages has matched
and present them separately with separate scores.
It's really the core issue to decide on. What are
the benefits and
drawbacks of the different solutions. For each solution is there something
in the UI that you cannot do ?
So far I've heard:
1/ Presenting different scores for documents in different languages with
the same doc name if the title_fr,content_fr method is used
Since we are not considering the one-document-for-all-languages solution,
this is not an issue.
2/ Merging scores accross indexes in multicore approach
Other ? Can we list them in a wiki page ?
in
This is not a good solution. If I understand correctly we could not end up
not searching in a french attachment because the original document is in
marked "en".
I'm for Paul's solution to index objects and attachments in each
translation (if we have separate entities for translated documents).
Yep, we already do this for objects, just need to do it for attachments as
well.
>
> In the future if we are able to "detect" the language of the documents
we
> could add a lucene field with the
"detected" language instead of the
> "provided" language of the documents, therefore increasing the quality
of
searches
only on documents of a specific language.
In the previous discussions (on the GSoC thread) we agreed that language XWiki is known before-hard, so no recognition is
required, at least not
at
document level.
Let's forget this
>
> This later solution would be the only one that would really work on
file
attachements as we have no information about the specific language of
file
attachements (or even XWiki objects) which are
attached to the main
document and not to the translated document.
Yes, this is a problem right now. AFAIU, the plan [1] is to support
translated objects and maybe attachments as well. Until then, we could
either:
1) Use the original document's language to index the attachment's content
I
understand that in the title_fr,content_fr approach this problem does not
happen.
This problem is not related to how we handle multiple translations
(separate indexes or not), as long as each translation is a separate
entity. Basically this last part is the problem. If the French translation
is a separate entity from the original document (i.e. that is in English),
any object/attachment *index field* of the English original version will
need to be duplicated into the French translation as well, or the French
translation risks not to get a hit on the object/attachment.
2) Use a language detection library to try to
detect the attachment
content's language and index it accordingly.
Not sure we can for now
The above could also be applied for objects and
their properties.
----------
[1] http://jira.xwiki.org/browse/XWIKI-69
called
This later issues shows that a search on "only french content" should
still
include the attachements because we have no idea
if the attachments are
"french" or "english".
(The paragraphs below discuss on what currently exists and what could be
done, ignoring the possible language detection mentioned above)
Right now a document also indexes the object's properties in a field "objcontent". I do this for all
translations, thus duplicating the
field's
value in all translations. I can do the same for
attachments. The purpose
is, indeed, to be able to find document translations based on hits in
their
objects/attachments. If a language filter is used
and there is a hit in
an
object, only one document is returned. If there
are no language filters,
all translations will be returned.
It seems we have to do this for now
However, if we search for the object/property/attachment itself, it will
only be assigned to one language: the language of the original document.
This means that if we search for all languages, the object itself will be
found too (there is no language filter used). If we add a language filter
that is different from the object/property/attachment's original document
language, the object/property/attachment will not be found.
Maybe we can come up with some processing of the query in the search
application, that applies the language filter only for documents:
((-type:"OBJECT" OR -type:"OBJECT_PROPERTY" OR
-type:"ATTACHMENT") OR
lang:"<userSelectedLanguage>") -- writing it like this because the
default
operand is AND in the query filter clause that we
use in the Search
application.
The problem with this is that that, when a language filter is used, the
object/property/attachments that are now included in the results might
not
have the specified language and will pollute the
results.
I'm not sure I understand. We have an "objcontent" field for each
translation that has the full content of objects and properties, but
individual object fields we don't have in each translations ?
The more I see all the issues, the more I lean towards
a separate index per
language solution.
Again, these issues are not related to this, just to the fact that Document
translations are first-class Lucene documents.
The reason I do is that the main need is for a non
English user to have very relevant results in his own language. Therefore
we need to make sure that all content that the users have published has the
chance to be analyzed using the non English language analyzer. So indexing
all objects and attachments with the relevant language analyzer is the
solution. This is also why I proposed to index all content in this specific
index regardless of the language declared, which would only be used in the
UI to limit searches to the specific language.
In this view:
0/ There would be a language specific index per language with the objects
and attachments indexed only in the language of the index
1/ The user chooses the language in which he searches
2/ Automatically that sets the index to be used to be the "french" index
3/ Automatically that presets to limit the span of the search to declared
"french" documents
4/ The user can decide to go for non french documents at his own risks
knowing that the results might be weird because of wrong analysis (this is
what happens today with english analysis over french documents)
The benefit here is that you don't have a merging score over multiple index
issue, since you would never have to do a search across multiple indexes.
Searches are still simple to write. By default results are quite relevant
since you limit the search the french declared documents (this would be the
same as limiting your search to title_fr, content_fr) and still cover what
needs to be covered (objects and attachments).
Another benefit is that this falls back gracefully to monolingual as you
just have to have one index in the language declared for the monolingual
wiki.
The drawback is that the indexing is more costly and there is duplicated
content in the index. Howerver it is the Admin that say which languages he
wants available and he takes responsibility of the ressources this needs.
Could this solution work ?
Unfortunately I am still not convinced by this approach. Besides the
complexities of managing multiple cores (each with it's own schema and
config files), the user is exposed to a lot of unnecessary badly indexed
data that will make him stay away from the search feature, as it has
happened with Lucene so far.
I believe this discussion thread has come up with some nice solutions to
most of our problems and that the multiple-fields direction is one that can
give us relevant results, properly indexed content for all languages (even
when searching in all languages) and a good solution for objects,
attachments and properties (though, again, this is not related to this
specific choice).
I will try to make a summary of the ideas from this thread and put them
into a wiki page that documents the design/progress of the multi-lingual
related work.
Thank you very much for now and, of course, this does not mean that the
discussion is over in any way :)
-Eduard
Ludovic
not
*new*
enygma2002(a)gmail.com
approach.
full
that
clauses
query
Because
default
an
andhides
fields
stemming.
> > >> My experience, which was before dismax on curriki.org, has made
it
box.
http://mail-archives.apache.org/mod_mbox/lucene-solr-user/201211.mbox/%3Cza…
to
that
match
> > >> single in one language.
> > >>
> > >> However, indicating which language it is matched into is probably
> > >> useful...
> > >>
> > >
> > > Already doing that.
> > >
> > >
> > >> Funnily, cross-language-retrieval is a mature research field but
> > >> retrieval for multilanguage user is not so!
> > >>
> > >> > On a related note, I have also watched an interesting
presentation
German
forced
filesystem.
but
good
> > >> idea.
> > >> Also, it is very common that users formulate queries without
> formulating
> > >> their language and thus you need to "or" the user's
queries through
will
problem
list
on-the-fly,
since
separate
previous
> > > experience on the topic, so I`m still doing mostly guesswork in
some
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--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
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Thanks,
Eduard
zip
Ludovic
2012/11/26 Eduard Moraru <enygma2002(a)gmail.com>
> Hi devs,
>
> Any other input on this matter?
>
> To summarize a bit, if we go with the multiple fields for each
language,
> we
> > end up with an index like:
> >
> > English version:
> > id: xwiki:Main.SomeDocument_en
> > language: en
> > space: Main
> > title_en: XWiki document
> > doccontent_en: This is some content
> >
> > French version:
> > id: xwiki:Main.SomeDocument_fr
> > language: fr
> > space: Main
> > title_fr: XWiki document
> > doccontent_fr: This is some content
> >
> > The Solr configuration is generated by some XWiki UI that returns a > > that the admin has to unpack in his
(remote) Solr instance. This
could
be
> > automated for the embedded instance. This operation is to be
performed
> each
> > time an admin changes the indexed languages (rarely or even only
once).
> >
> > Querying such a schema is a bit tricky when you are interested in
more
than
fields
> > like "title" and "doccontent" and to put as values very
lightly (or one language, because you have to add all the
clauses (title_en,
title_fr,
etc.) specific to the languages you are
interested in.
Some extra fields might also be added like title_ws (for whitespace
tokenization only) that have various approaches to the indexing
operation,
> with the aim of improving the relevancy.
>
> One solution to simplify the query for API clients would be to use > at
> > all) analyzed content, as Paul suggested. This would allow
applications
> to
> > write simple (and backwards compatible maybe) queries that will still
> work,
> > but will not catch some of the nuances of specific languages. As far
as
> I`ve
seen until now, applications are not very interested in nuances,
but
> rather in filtering the results, a task for
which this solution might
be
> > well suited. Of course, nothing stops applications from using the and
> more expressive fields that are properly analized.
>
> Thus, the search application will be the major beneficiary of these
> analyzed fields (title_en, title_fr, etc.), while still allowing
> applications to get their job done (trough generic, but less/not
analized
> > fields like "title", "doccontent", etc.).
> >
> > WDYT?
> >
> > Thanks,
> > Eduard
> >
> >
> >
> >
> > On Wed, Nov 21, 2012 at 10:49 PM, Eduard Moraru < >
>wrote:
>
> > Hi Paul,
> >
> > I was counting on your feedback :)
> >
> > On Wed, Nov 21, 2012 at 3:04 PM, Paul Libbrecht <paul(a)hoplahup.net
> wrote:
> >
> >>
> >> Hello Eduard,
> >>
> >> it's nice of you to see you take this further.
> >>
> >> > This issue has already been previously [1] discussed during the
GSoC
> > >> > project, but I am not particularly happy with the chosen > > >> > When handling multiple
languages, there are generally[2][3] 3
> > different
> > >> > approaches:
> > >> >
> > >> > 1) Indexing the content in a single field (like title,
doccontent,
>
etc.)
> >> > - This has the advantage that queries are clear and fast
> >> > - The disadvantage is that you can not run very well tuned
analyzers
> on
> >> the
> >> > fields, having to resort to (at best) basic tokenization and
> >> lowercasing.
> >> >
> >> > 2) Indexing the content in multiple fields, one field for each
> language
> >> > (like title_en, title_fr, doccontent_en, doccontent_fr, etc.)
> >> > - This has the advantage that you can easily specify (as dynamic
> fields)
> >> > that *_en fields are of type text_en (and analyzed by an
> >> english-centered
> >> > chain of analyzers); *_fr of type text_fr (focused on french,
etc.),
> > >> thus
> > >> > making the results much better.
> > >>
> > >> I would add one more field here: title_ws and text_ws where the >
text
> >> is analyzed just as words (using the whitespace-tokenizer?).
> >> A match there would even be preferred to a match in the below
> text-fields.
> >>
> >> (maybe that would be called title and text?)
> >>
> >> > - The disadvantage is that querying such a schema is a pain. If
you
> > want
> > >> > all the results in all languages, you end up with a big and
> expensive
> > >> > query.
> > >>
> > >> Why is this an issue?
> > >> Dismax does it for you for free (thanks to the "form"
parameter >
>> gives weight to each of the fields).
> >> This is an issue only if you start to have more than 100 languages
or
> > >> so...
> > >> Lucene, the underlying engine of solr, handles thousands of in a
> >> query without an issue (this is how prefix-queries are handled...
they
> are
> >> expanded to a query for any of the term that matches the prefix, a
> setting
> >> deep somewhere, which is about 2000 avoids this to explode).
> >>
> >
> > Sure, Solr is great when you want to do simple queries like "XWiki
Open
> > > Source", however, since in XWiki we also expose the Solr/Lucene
> > APIs
> > > to the platform, there will be (as as it is currently with Lucene)
a
lot
> of
> > extensions wanting to do search using this API. These extensions
(like
> the
> > search suggest for example, rest search, etc) want to do something
like
> > > "title:'Open Source' AND type:document AND
doccontent:XWiki". > >
option 2) is so messy in it's fields, it would mean that the
extension
> > > would have to come up with a query like "title_en:'Open
Source' AND
> > > type:document AND doccontent_en:XWiki" (assuming that it is only
> limited
> > to
> > > the current -- english or whatever -- language; what happens if it
> wants
> > to
> > > do that no matter what language? It will have to specify each
> combination
> > > possible because we can't use generic field names).
> > >
> > > Solr's approach works for using it in your web application's
search
> > input,
> > > in a specific usecase, where you have precisely specified the > > > search fields and their boosts
inside your schema.xml. However, as
a
>
search
> > API, using option 2) you are making the life of anyone else wanting
to
> > use
> > > the Solr search API really hard. Also, your search application will
> work
> > > nicely when the user enters a simple query in the input field, but > > > advanced user will suffer the same
fate when trying to write an
> advanced
> > > query, thus not relying on the default query (computed by solr
based
on
all
> > schema.xml).
> >
> > Also, based on your note above regarding improvements like title_ws
and
> > > such, again, all of these are very well suited for the search
> application
> > > use case, together with the default query that you configure in
> > schema.xml,
> > > making the search results perform really well. However, what does >
these
> > fields mean to another extension wanting to do search? Will it have
to
> > handle all these implementation details
to query for title, content
and
> > such? I`m not sure how well this would
work in practice.
> >
> > Unrealistic idea(?): perhaps we should come up with an abstract
search
> > > language (Solr/Lucene clone) that parses the searched fields > the
> > > complexities of all the indexed fields, allowing to write simple
> queries
> > > like "title:XWiki", while this gets translated to
"title_en:XWiki
OR
> >
title_fr:XWiki OR title_de:XWiki..." :)
> >
> > Am I approaching this wrong by trying to have both a
tweakable/tweaked
> > search application AND a search API?
Are the two not compatible? Do
we
> have
> > to sacrifice search result performance (no language-specific stuff)
to
> be
> > > able to have a usable API?
> > >
> > >
> > >> > If you want just some language, you have to read the right > > >> > (ex title_en) instead of
just getting a clear field name
(title).
>>
>> You have to be careful, this is really only if you want to be
specific.
> >> In this case, it is likely that you also do not want so much so
concern,
a
>>
that any query that is a bit specific is likely to not desire
stemming.
>>
>
> Can you please elaborate on this? I`m not sure I understand the
problem.
> >
> >
> >>
> >> > -- Also, the schema.xml definition is a static one in this > >> > requiring you to know
beforehand which languages you want to
support
> > >> (for
> > >> > example when defining the default fields to search for). Adding
new
> >> > language requires you to start editing the xml files by hand.
> >>
> >> True but the available languages are almost all hand-coded.
> >> You could generate the schema.xml based on the available languages
if
> not
> >> hand-generated?
> >>
> >
> > Basically I would have to output a zip with schema.xml,
solrconfig.xml
> > and
> > > then all the resources specific to all the selected languages
> (stopwords,
> > > synonims, etc) for the languages that we can provide out of the > For
> > > other languages, the admin would have to get dirty with the xmls.
> > >
> > >
> > >>
> > >> There's one catch with this approach which is new to me but seems
to
> be
> > >> quite important to implement this approach: the idf should be
> modified,
> > the
> > >> Similarity class should be, so that the total number of documents
is
the
>> total number of documents having that
language.
>> See:
>>
>>
> > >> The solution sketched there
sounds easy but I have not tried it.
> > >>
> > >> > 3) Indexing the content in different Solr cores (indexes), one
for
> > each
> > >> > language. Each core requires it's on directory and
configuration
> > files.
> > >> > - The advantage is that queries are clean to write (like option
1)
and
> >> that
> >> > you have a nice separation
> >> > - The disadvantage is that it's difficult to get it right
> >> (administrative
> >> > issues) and then you also have the (considerable) problem of
having
to
to
> a
> > >> > remote Solr instance the configuration files when creating a new
> core
> > >> > programatically. However, if we are running an embedded Solr
> instance,
> > >> we
> > >> > could provide a way to generate the config files and write them
>> fix
>> > the relevancy score of a query result that has entries from
different
>> > cores; each core has it's own
relevancy computed and does not
consider
> >> the
> >> > others.
> >> > - To make it even worst, it seems that you can not [5] also push
the
> >> data
> >> > directory.
> >>
> >> Post-processing results is very very very dangerous as performance
is
> at
> > >> risk (e.g. if a core does not answer)... I would tend to avoid as
the
> much
> >> as possible.
> >>
> >
> > Not really related, but this reminds me about the post processing
that
> I
> > > do for checking view rights over the returned result, but that's
> another
> > > discussion that we will probably need to have :)
> > >
> > >
> > >>
> > >> > Currently I have implemented option 1) in our existing Solr
> > integration,
> > >> > which is also more or less compatible with our existing Lucene
> > queries,
> > >> but
> > >> > I would like to find a better solution that actually analyses
>
>> content.
> >> >
> >> > During GSoC, option 2) was preferred but the implementation did
not
>>
> consider practical reasons like the ones described above (query
>> complexity,
>> > user configuration, etc.)
>>
>> True, Savitha surfed the possibility of having different solr
documents
> >> per language.
> >> I still could not be sure that this was not showing the document > [3]
> > >> > about how Drupal handles its Solr integration and,
particularly, a
>
>> plugin
> >> > [4] that handles the multilingual aspect.
> >> > The idea seen there is that you have this UI that helps you
generate
> > >> > configuration files, depending you your needs. For instance, you
> > (admin)
> > >> > check that you need search for language English, French and
and
> >> the
> >> > ui/extension gives you a zip with the configuration you need to
use
> in
> > >> your
> > >> > (remote or embedded) solr instance. The configuration for each
> > language
> > >> > comes preset with the analyzers you should use for it and the
> > additional
> > >> > resources (stopwords.txt, synonims.txt, etc.).
> > >> > This approach helps with avoiding the need for admins to be
> to
> > >> edit
> > >> > xml files and could also still be useful for other cases, not
only
> > >> option
> > >> > 2).
> > >>
> > >> Generating sounds like an easy approach to me.
> > >>
> > >
> > > Yes, however I don`t like the fact that we can not do everything
from
> the
> > > webapp and the admin needs to access the filesystem to install the
> given
> > > configuration on the embedded/remote solr directory. Lucene does
not
have
> > this problem now. It just works with XWiki and everything is done
from
> > XWiki UI. I feel that losing this
commodity will not be very well
> received
> > by users that now have some new install steps to get XWiki running.
> >
> > Well, of course, for the embedded solr version, we could handle it
like
> > we
> > > do now and push the files directly from the webapp to the > > Since
> > > embedded will be default, it should be OK and avoid the extra
install
>
step.
> > Users with a remote solr machine should have the option to get the
zip
> > > instead.
> > >
> > > Not sure if we can apply the new configuration without a restart, >
I`ll
> > have to look more into it. I know the multi-core architecture
supports
> > something like this but will have to
see the details.
> >
> >
> >>
> >> > All these problems basically come from the fact that there is no
way
> to
> >> > specify in the schema.xml that, based on the value of a field
(like
the
>> > field "lang" that stores the document language), you want to run
this
> or
> >> > that group of analyzers.
> >>
> >> Well, this is possible with ThreadLocal but is not necessarily a > > >> multiple languages (e.g. given
by the browser).
> > >>
> > >> > Perhaps a solution would be a custom kind of
"AggregatorAnalyzer"
> that
> > >> > would call other analyzers at runtime, based on the value of the
> lang
> > >> > field. However, this solution could only be applied at index
time,
> > when
> > >> you
> > >> > have the lang information (in the solrDocument to be indexed),
but
> > when
> > >> you
> > >> > perform the query, you can not analyze the query text since you
do
not
> >> know
> >> > the language of the field you're querying (it was determined at
> runtime
> >> -
> >> > at index time) and thus do not know what operations to apply to
the
> > >> query
> > >> > (to reduce it to the same form as the indexed values).
> > >>
> > >> How would that look at query time?
> > >>
> > >
> > > That's what I was saying, that at query time, the searched term not
> > get analyzed by the right chain. When you search for a single
language,
> you
> > could add that language as a query filter and then you could apply
the
> > > right chain, but when searching in 2 or more (or no, meaning all)
> > languages
> > > you are stuck.
> > >
> > >>
> > >> > I have also read another interesting analysis [6] on this that
> >> > elaborates on the complexities and limitations of each options.
> (Ignore
> >> the
> >> > Rosette stuff mentioned there)
> >> >
> >> > I have been thinking about this for some time now, but the
solution
is
> >> > probably somewhere in between, finding an option that is
acceptable
> > >> while
> > >> > not restrictive. I will probably also send a mail on the Solr
> to
> > >> get
> > >> > some more input from there, but I get the feeling that whatever
> > >> solution we
> > >> > choose, it will most likely require the users to at least copy
(or
>
even
> >> > edit) some files into some directories (configurations and/or
jars),
> > >> since
> > >> > it does not seem to be easy/possible to do everything >
>> > programatically.
> >>
> >> The only hard step is when changing the supported languages, I
think.
> > >> In this case, when automatically generating the index, you need to
> warn
> > >> the user.
> > >> The admin UI should have a checkbox "use generated schema"
or a
> textarea
> > >> for the schema.
> > >>
> > >
> > > Please see above regarding configuration generation. Basically, we
> > are going to support both embedded and remote solr instances, we
could
> > support things like editing the schema
from XWiki only for the
embedded
> > > instance, but not for the remote one. We might end up having > UIs
> > > for each case, since we might want to exploit the flexibility of
the
> >
embedded one as much as possible.
> >
> >
> >>
> >> Those that want particular fields and tunings need to write their
own
> >> schema.
> >>
> >> The same UI could also include whether to include a phonetic track
or
not
>> (then require reindexing).
>
>
>> hope it helps.
>>
>
> Yes, very helpful so far. I`m counting on your expertise with
Lucene/Solr
> > on the details. My current approach is a practical one without areas.
>
> Thanks,
> Eduard
>
>
>> paul
>> _______________________________________________
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>>
>
>
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Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
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