11 Oct
2013
11 Oct
'13
11:55 a.m.
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
11 Oct
11 Oct
12:05 p.m.
On Fri, Oct 11, 2013 at 11:55 AM, Marius Dumitru Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Sounds good in theory but storing several entities in the same entry
has complexity of it's own that needs to be discussed before deciding.
How do you plan to store several tag objects of the same document in a
single document entry for example ?
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
--
Thomas Mortagne
12:14 p.m.
On Fri, Oct 11, 2013 at 1:05 PM, Thomas Mortagne
<thomas.mortagne(a)xwiki.com> wrote:
On Fri, Oct 11, 2013 at 11:55 AM, Marius Dumitru
Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Sounds good in theory but storing several entities in
the same entry
has complexity of it's own that needs to be discussed before deciding.
I agree.
How do you plan to store several tag objects of the same document in a
single document entry for example ?
I haven't thought very much but I was thinking about using
multiValued="true" maybe in combination with dynamic fields. I need to
think about this.
Thanks,
Marius
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
--
Thomas Mortagne
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs 
12:09 p.m.
Hi,
I don't want to answer this too broadly (I don't have the technical chops
to make a really informed comment). Here's however what I can state from my
experience with XWiki projects:
- When searching for an attached file, we always want to know (and
display) the document to which that file is attached
- When searching for an object, we're always looking for the document
which the object is part of, especially since we don't have an
"object-only" or "property-only" view anyway
- When searching for a class, again, we don't have a displayer for that
class in view mode outside of the document holding the class
- We don't really search for a space right now since technically it's
just a collection of pages anyway
- Searching for a wiki would be done through the wiki index, other than
that you're just searching for documents (some of which might happen to be
in a wiki)
All of which would tend to agree with Marius' suggestion.
In terms of UX impact, I think this would mean that documents should always
be returned in search results, with attachments indented under the document
itself (instead of having separate entries for attachments and documents as
we do now).
Guillaume
On Fri, Oct 11, 2013 at 11:55 AM, Marius Dumitru Florea <
mariusdumitru.florea(a)xwiki.com> wrote:
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
12:17 p.m.
On Fri, Oct 11, 2013 at 1:09 PM, Guillaume Lerouge <guillaume(a)xwiki.com> wrote:
Hi,
I don't want to answer this too broadly (I don't have the technical chops
to make a really informed comment). Here's however what I can state from my
experience with XWiki projects:
- When searching for an attached file, we always want to know (and
display) the document to which that file is attached
- When searching for an object, we're always looking for the document
which the object is part of, especially since we don't have an
"object-only" or "property-only" view anyway
- When searching for a class, again, we don't have a displayer for that
class in view mode outside of the document holding the class
- We don't really search for a space right now since technically it's
just a collection of pages anyway
- Searching for a wiki would be done through the wiki index, other than
that you're just searching for documents (some of which might happen to be
in a wiki)
All of which would tend to agree with Marius' suggestion.
In terms of UX impact, I think this would mean that
documents should always
be returned in search results, with attachments indented under the document
itself (instead of having separate entries for attachments and documents as
we do now).
Yes, the results would always be documents but for each result we
would display where the search term has been matched:
* in document title
* in document content
* in the attachment name
* in the attachment content
* in an object property
* etc.
Thanks,
Marius
Guillaume
On Fri, Oct 11, 2013 at 11:55 AM, Marius Dumitru Florea <
mariusdumitru.florea(a)xwiki.com> wrote:
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs 
12:26 p.m.
Hi,
From my point of view we usually search mostly for two
types of things:
- documents
- attachements
But we should be able to filter these results on multiple property values
of any object. This is true also for documents and for attachments.
It is also interesting to be able to present results differently depending
on the document we get (if it's has meeting document or a user document we
display things differently)
Being able to search for attachments separately is very important.
As for objects most of the time we search for documents that have this
specific object.
There is however a use case I see where it could be interesting to search
in individual objects.
For example this is the case for comments. It could be interesting to make
a search in all comments.
Another example could be tasks. Suppose you add tasks inside documents
associated to some content of the document (like annotations).
You might want to be able to make some nice search on all the tasks and
then display a link to the document in which the task is but not the other
way around.
Now I think this use case could be optional, so we don't necessarly need to
index all objects of all classes. We could have some config which tells to
make an index for all comments objects or all task objects. I think we
already had an object index in lucene and I don't remember if we have ever
used it.
I don't think we need an index on all properties.
Ludovic
2013/10/11 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
12:28 p.m.
As for the searching for "wiki" example, this is a good case where in
really we just need to search for documents since one wiki = one document.
The only case where we could need to search for objects is when 1 document
= multiple objects and it's not that common and even less comment that we
need to make full take searches on the object entities separately.
Ludovic
2013/10/11 Ludovic Dubost <ludovic(a)xwiki.com>
Hi,
From my point of view we usually search mostly for two types of things:
- documents
- attachements
But we should be able to filter these results on multiple property values
of any object. This is true also for documents and for attachments.
It is also interesting to be able to present results differently depending
on the document we get (if it's has meeting document or a user document we
display things differently)
Being able to search for attachments separately is very important.
As for objects most of the time we search for documents that have this
specific object.
There is however a use case I see where it could be interesting to search
in individual objects.
For example this is the case for comments. It could be interesting to make
a search in all comments.
Another example could be tasks. Suppose you add tasks inside documents
associated to some content of the document (like annotations).
You might want to be able to make some nice search on all the tasks and
then display a link to the document in which the task is but not the other
way around.
Now I think this use case could be optional, so we don't necessarly need
to index all objects of all classes. We could have some config which tells
to make an index for all comments objects or all task objects. I think we
already had an object index in lucene and I don't remember if we have ever
used it.
I don't think we need an index on all properties.
Ludovic
2013/10/11 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
2:48 p.m.
On Fri, Oct 11, 2013 at 1:26 PM, Ludovic Dubost <ludovic(a)xwiki.com> wrote:
Hi,
From my point of view we usually search mostly for two types of things:
- documents
- attachements
But we should be able to filter these results on multiple property values
of any object. This is true also for documents and for attachments.
It is also interesting to be able to present results differently depending
on the document we get (if it's has meeting document or a user document we
display things differently)
Being able to search for attachments separately is
very important.
This was possible with the old Lucene index because we were indexing
attachments in separate rows _but_ we were duplicating all document
fields on the attachment row. So if you had a document with 2
attachments then you had 3 rows associated in the Lucene index: one
for the document itself and 2 for the attachments but the document
fields were duplicated twice. Of course we can say we don't care about
the index size (do we? :) ) but we must be careful to not get
duplicated results because of the duplicated information in the index.
Thanks,
Marius
As for objects most of the time we search for documents that have this
specific object.
There is however a use case I see where it could be interesting to search
in individual objects.
For example this is the case for comments. It could be interesting to make
a search in all comments.
Another example could be tasks. Suppose you add tasks inside documents
associated to some content of the document (like annotations).
You might want to be able to make some nice search on all the tasks and
then display a link to the document in which the task is but not the other
way around.
Now I think this use case could be optional, so we don't necessarly need to
index all objects of all classes. We could have some config which tells to
make an index for all comments objects or all task objects. I think we
already had an object index in lucene and I don't remember if we have ever
used it.
I don't think we need an index on all properties.
Ludovic
2013/10/11 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs 
13 Oct
13 Oct
11:27 p.m.
Hi,
The initial idea with modelling things this way in the Solr index was to
allow devs to be able to search for other entities than documents (objects
and their properties) using Solr instead of having to use (HS/XW)QL.
An interesting use case from my POV was when a dev wanted to search for a
piece of code (but could be just a word/string) that is stored in an XWiki
object. We keep assuming that everybody stores one object in one document,
but it`s obviously not the case every time and, some app devs might want to
store their application`s entities as multiple objects inside a single page
(since we always have that dilemma when starting to dev an application).
Also, another example was mentioned by Ludovic with XWikiComments.
The problem in the previous mapping was that we would find out the document
where the object is stored, but we would not know in which actual object
that result is found, since we indexed property values in the form of
CassName.propertyName:value. So telling the dev that the string/code/etc
he's looking for is somewhere in that document does not help much.
Using Solr, we might now know which field (propertyName) that was (with the
highlighting component), but we would probably need to add some object
ID/number information in there (like CassName.0.propertyName:value) and
that might mess up the query syntax. We would have to write queries like
CassName.*.propertyName:searchedWord and I don`t remember if Solr supports
the usage of wildcards in field names (AFAIR, only in field values, except
for the catch-all *:* construction). AFAIR, this was the main reason why we
had to use dynamic fields and the whole multilingual work.
I also had my doubts about mapping properties as first class Lucene
documents (or "tables" as previously referred), but, now that I think of
it, it provides a solution for the example above. Maybe using just objects
would have sufficed as well. I don`t know, more examples may exist or not,
but it's good that we`ve started talking about it.
Marius, if you`re interested, I`m available this starting week for some
brainstorming on the subject, if that would help. Just let me know.
Thanks,
Eduard
On Fri, Oct 11, 2013 at 3:48 PM, Marius Dumitru Florea <
mariusdumitru.florea(a)xwiki.com> wrote:
On Fri, Oct 11, 2013 at 1:26 PM, Ludovic Dubost
<ludovic(a)xwiki.com> wrote:
Hi,
From my point of view we usually search mostly for two types of things:
- documents
- attachements
But we should be able to filter these results on multiple property values
of any object. This is true also for documents and for attachments.
It is also interesting to be able to present results differently
depending
on the document we get (if it's has meeting
document or a user document
we
display things differently)
Being able to search for attachments separately
is very important.
This was possible with the old Lucene index because we were indexing
attachments in separate rows _but_ we were duplicating all document
fields on the attachment row. So if you had a document with 2
attachments then you had 3 rows associated in the Lucene index: one
for the document itself and 2 for the attachments but the document
fields were duplicated twice. Of course we can say we don't care about
the index size (do we? :) ) but we must be careful to not get
duplicated results because of the duplicated information in the index.
Thanks,
Marius
As for objects most of the time we search for documents that have this
specific object.
There is however a use case I see where it could be interesting to search
in individual objects.
For example this is the case for comments. It could be interesting to
make
a search in all comments.
Another example could be tasks. Suppose you add tasks inside documents
associated to some content of the document (like annotations).
You might want to be able to make some nice search on all the tasks and
then display a link to the document in which the task is but not the
other
way around.
Now I think this use case could be optional, so we don't necessarly need
to
index all objects of all classes. We could have
some config which tells
to
make an index for all comments objects or all
task objects. I think we
already had an object index in lucene and I don't remember if we have
ever
used it.
I don't think we need an index on all properties.
Ludovic
2013/10/11 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
14 Oct
14 Oct
6 p.m.
I started writing
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema . I need help
with two things:
* test cases http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HTestCases
* if time permits, review the proposal, especially
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HAMixedApproach
.
Thanks,
Marius
On Fri, Oct 11, 2013 at 12:55 PM, Marius Dumitru Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that class?
* are you searching for a wiki without caring about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
13 Nov
13 Nov
7:08 p.m.
Hi Marius,
I have a quick question when starting reading your proposal. I don't see
anything about multi language indexing.
I remember in the current SOLR implementation that there are multiple
fields for each language. Would there be a fields for each language indexed
for each property ?
Ludovic
2013/10/14 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
I started writing
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema . I need help
with two things:
* test cases
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HTestCases
* if time permits, review the proposal, especially
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HAMixedApproach
.
Thanks,
Marius
On Fri, Oct 11, 2013 at 12:55 PM, Marius Dumitru Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring
about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
14 Nov
14 Nov
5:28 p.m.
On Wed, Nov 13, 2013 at 8:08 PM, Ludovic Dubost <ludovic(a)xwiki.com> wrote:
Hi Marius,
I have a quick question when starting reading your proposal. I don't see
anything about multi language indexing.
I remember in the current SOLR implementation that there are multiple
fields for each language. Would there be a fields for each language indexed
for each property ?
Yes. Right now I'm struggling to find a way to define an alias for a
group of dynamic fields. For document title we have this in
solrconfig.xml
<str name="f.title.qf">title__ title_ar title_bg title_ca ...</str>
which makes 'title' an alias for all its translations and allows us to
write title:text in the search query. I need to do the same, but
dynamically, for each object property:
property_Blog.BlogPostClass_title =
property_Blog.BlogPostClass_title__,
property_Blog.BlogPostClass_title_en,
property_Blog.BlogPostClass_title_fr, ...
I'll keep you posted.
Thanks,
Marius
Ludovic
2013/10/14 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
I started writing
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema . I need help
with two things:
* test cases
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HTestCases
* if time permits, review the proposal, especially
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HAMixedApproach
.
Thanks,
Marius
On Fri, Oct 11, 2013 at 12:55 PM, Marius Dumitru Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring
about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
15 Nov
15 Nov
12:02 a.m.
Marius,
I would suggest to generate the schema and config, reloading every time there's a
class change.
Alternatively, and that's how solr-drupal works, you would define the fields by prefix
but I am not sure the aliassing would work.
I believe that the query-expansion step, from title:x to title-en:x title-ft:x, etc… is
best to be controlled early so that applications can change that somehow. In curriki, this
is done with a custom query-component which uses the query-parser (with a default-field
which does not exist) then rewrites the query objects (which is a fairly easy game).
Hope it helps.
Le 14 nov. 2013 à 17:28, Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com> a
écrit :
On Wed, Nov 13, 2013 at 8:08 PM, Ludovic Dubost
<ludovic(a)xwiki.com> wrote:
Hi Marius,
I have a quick question when starting reading your proposal. I don't see
anything about multi language indexing.
I remember in the current SOLR implementation that there are multiple
fields for each language. Would there be a fields for each language indexed
for each property ?
Yes. Right now I'm struggling to find a way to define an alias for a
group of dynamic fields. For document title we have this in
solrconfig.xml
<str name="f.title.qf">title__ title_ar title_bg title_ca
...</str>
which makes 'title' an alias for all its translations and allows us to
write title:text in the search query. I need to do the same, but
dynamically, for each object property:
property_Blog.BlogPostClass_title =
property_Blog.BlogPostClass_title__,
property_Blog.BlogPostClass_title_en,
property_Blog.BlogPostClass_title_fr, ...
I'll keep you posted.
Thanks,
Marius
Ludovic
2013/10/14 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs I started writing
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema . I need help
with two things:
* test cases
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HTestCases
* if time permits, review the proposal, especially
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HAMixedApproach
.
Thanks,
Marius
On Fri, Oct 11, 2013 at 12:55 PM, Marius Dumitru Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
--
Ludovic Dubost
Founder and CEO
Blog: http://blog.ludovic.org/
XWiki: http://www.xwiki.com
Skype: ldubost GTalk: ldubost
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs Hi devs,
This is a very important question so think carefully. Let me explain:
In XWiki (model) we have a few entity types. There are *wikis* which
have *spaces* which have *documents*. A document can have *objects*
and *attachments*. A document can also define a *class*.
At the same time we like to say that in XWiki "everything is a
document" because everything revolves around documents. The document
is the central notion.
We can query the database (using HQL or XWQL) for any of the
previously mentioned entities but what should a Solr query return
(semantically)? In other words:
* are you searching for an object without caring about the document
that holds the object? Same for an object property.
* how often are you searching for an attachment without caring about
the document that holds the attachment?
* are you searching for a class or for the document that defines that
class?
* are you searching for a wiki without caring
about the documents it
contains? Same for a space.
IMO the result of a Solr query should be, semantically, a list of
documents. But maybe I'm wrong.
-----------------------
Technical Details
-----------------------
Unlike a relational database, Solr/Lucene index has a single 'table'.
So normally you index a single entity type. Each row in the index
represents an entity of that type. As a consequence the result of a
Solr query is semantically a list of entities of that type. In our
case the entity type is (naturally) *document*.
If you want to index more entity types (e.g. index attachments and
objects _separately_, not as part of a document) then, since there is
only one 'table' in the index, you need to add a 'type' column that
specifies the type of entity you have on each row (e.g. type=document,
type=attachment, type=object etc.). The result of a Solr query is now,
semantically, a list of different entity types, unless you filter by a
specific type. It smells like a hack to me.
Let's imagine what happens if we want to search for blog posts that
has a specific tag. With the first approach this is easy because all
the (indexed) information is on a single row. With the second approach
this is considerably more complex because the information is spread on
multiple rows:
* one row with type=document for the blog post document
* one row with type=object for the blog post object
* one row with type=object for the tab object
In a relational database when you have the information spread in
multiple places (tables) you do joins. Fortunately (you would says)
Solr supports joins. In this particular case we would have to perform
2 joins which means:
index X index X index
where X represents the cartesian product. The document name would be
the join key. Pretty complex even before trying to write this in Solr
query syntax..
So basically the question becomes: is it worth indexing more entities
_separately_ instead of indexing just documents (with info about their
objects and attachments) considering the complexity that it brings in
writing Solr queries? Do we search for objects and attachments alone
as separate entities often enough to justify this complexity? My
answer is no.
Thanks,
Marius
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6:48 a.m.
On Fri, Nov 15, 2013 at 1:02 AM, Paul Libbrecht <paul(a)hoplahup.net> wrote:
Marius,
I would suggest to generate the schema and config,
reloading every time there's a class change.
That would mean re-indexing everything right? It would take to much time.
Alternatively, and that's how solr-drupal works,
you would define the fields by prefix but I am not sure the aliassing would work.
I believe that the query-expansion step, from title:x
to title-en:x title-ft:x, etc… is best to be controlled early so that applications can
change that somehow. In curriki, this is done with a custom query-component which uses the
query-parser (with a default-field which does not exist) then rewrites the query objects
(which is a fairly easy game).
That's actually what I'm currently investigating. I'll try to extend
the ExtendedDismaxQParserPlugin, let it do its query parsing and then
expand the query with more query objects when the "field" name matches
some pattern (e.g. property_*)
Thanks,
Marius
Hope it helps.
Le 14 nov. 2013 à 17:28, Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com> a
écrit :
On Wed, Nov 13, 2013 at 8:08 PM, Ludovic Dubost
<ludovic(a)xwiki.com> wrote:
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs Hi Marius,
I have a quick question when starting reading your proposal. I don't see
anything about multi language indexing.
I remember in the current SOLR implementation that there are multiple
fields for each language. Would there be a fields for each language indexed
for each property ?
Yes. Right now I'm struggling to find a way to define an alias for a
group of dynamic fields. For document title we have this in
solrconfig.xml
<str name="f.title.qf">title__ title_ar title_bg title_ca
...</str>
which makes 'title' an alias for all its translations and allows us to
write title:text in the search query. I need to do the same, but
dynamically, for each object property:
property_Blog.BlogPostClass_title =
property_Blog.BlogPostClass_title__,
property_Blog.BlogPostClass_title_en,
property_Blog.BlogPostClass_title_fr, ...
I'll keep you posted.
Thanks,
Marius
Ludovic
2013/10/14 Marius Dumitru Florea <mariusdumitru.florea(a)xwiki.com>
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devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs I started writing
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema . I need help
with two things:
* test cases
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HTestCases
* if time permits, review the proposal, especially
http://dev.xwiki.org/xwiki/bin/view/Design/SolrSchema#HAMixedApproach
.
Thanks,
Marius
On Fri, Oct 11, 2013 at 12:55 PM, Marius Dumitru Florea
<mariusdumitru.florea(a)xwiki.com> wrote:
> Hi devs,
>
> This is a very important question so think carefully. Let me explain:
>
> In XWiki (model) we have a few entity types. There are *wikis* which
> have *spaces* which have *documents*. A document can have *objects*
> and *attachments*. A document can also define a *class*.
>
> At the same time we like to say that in XWiki "everything is a
> document" because everything revolves around documents. The document
> is the central notion.
>
> We can query the database (using HQL or XWQL) for any of the
> previously mentioned entities but what should a Solr query return
> (semantically)? In other words:
>
> * are you searching for an object without caring about the document
> that holds the object? Same for an object property.
> * how often are you searching for an attachment without caring about
> the document that holds the attachment?
> * are you searching for a class or for the document that defines that
class?
> * are you searching for a wiki without caring about the documents it
> contains? Same for a space.
>
> IMO the result of a Solr query should be, semantically, a list of
> documents. But maybe I'm wrong.
>
> -----------------------
> Technical Details
> -----------------------
>
> Unlike a relational database, Solr/Lucene index has a single 'table'.
> So normally you index a single entity type. Each row in the index
> represents an entity of that type. As a consequence the result of a
> Solr query is semantically a list of entities of that type. In our
> case the entity type is (naturally) *document*.
>
> If you want to index more entity types (e.g. index attachments and
> objects _separately_, not as part of a document) then, since there is
> only one 'table' in the index, you need to add a 'type' column that
> specifies the type of entity you have on each row (e.g. type=document,
> type=attachment, type=object etc.). The result of a Solr query is now,
> semantically, a list of different entity types, unless you filter by a
> specific type. It smells like a hack to me.
>
> Let's imagine what happens if we want to search for blog posts that
> has a specific tag. With the first approach this is easy because all
> the (indexed) information is on a single row. With the second approach
> this is considerably more complex because the information is spread on
> multiple rows:
>
> * one row with type=document for the blog post document
> * one row with type=object for the blog post object
> * one row with type=object for the tab object
>
> In a relational database when you have the information spread in
> multiple places (tables) you do joins. Fortunately (you would says)
> Solr supports joins. In this particular case we would have to perform
> 2 joins which means:
>
> index X index X index
>
> where X represents the cartesian product. The document name would be
> the join key. Pretty complex even before trying to write this in Solr
> query syntax..
>
> So basically the question becomes: is it worth indexing more entities
> _separately_ instead of indexing just documents (with info about their
> objects and attachments) considering the complexity that it brings in
> writing Solr queries? Do we search for objects and attachments alone
> as separate entities often enough to justify this complexity? My
> answer is no.
>
> Thanks,
> Marius
_______________________________________________
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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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8:01 a.m.
Hello Marius,
No for most cases.
A Lucene index is "just" a heap of "terms".
If you change the schema in that you add a new field, the impact on the index is zero.
If you rename a field, you need to reindex.
If you change the type of a field (or its analyzer) then you have to reindex.
If you delete a field, you leave some dirt, you'd have to reindex if you rewake this
field name.
I am not sure it's best practice, but as an application developer, I would enjoy if
this code was in a Groovy page.
paul
I would
suggest to generate the schema and config, reloading every time there's a class
change.
That would mean re-indexing everything right? It would take to much time. I believe that
the query-expansion step, from title:x to title-en:x title-ft:x, etc… is best to be
controlled early so that applications can change that somehow. In curriki, this is done
with a custom query-component which uses the query-parser (with a default-field which does
not exist) then rewrites the query objects (which is a fairly easy game).
That's actually what I'm currently investigating. I'll try to extend
the ExtendedDismaxQParserPlugin, let it do its query parsing and then
expand the query with more query objects when the "field" name matches
some pattern (e.g. property_*)
28 Nov
28 Nov
4:40 p.m.
Here's a short summary of what I implemented in the end:
* I'm using an encoding scheme similar to the URL-encoding to support
special characters in field names. I didn't use directly the
URL-encoding because '+' (plus) and '%' (percent) have special meaning
in Solr query syntax. Also, I didn't want to encode Unicode letters.
E.g. "Somé Spâce.Bob's Claß" is encoded as
"Somé$20Spâce.Bob$27s$20Claß"
* I wanted to be able to extract the class and property reference from
a field name in order to display the location where the search text
has been found. I couldn't use the default class / property reference
serialization syntax because '\' and '^' have special meaning in the
Solr query syntax. So I implemented a simple serialization syntax that
uses only '.' as entity separator and the dot is escaped by repeating
it.
E.g. "wiki:Some\.Space.My\.Class^color" is serialized as
"wiki.Some..Space.My..Class.color"
* I added the following fields to a document's index:
object : all types of objects found on the indexed document
object.Space.Class : collects values from all Space.Class properties
property.Space.Class.propName : indexes the values of
Space.Class^propName (multiple values if there are multiple objects of
type Space.Class)
* object.* and property.* are multilingual fields so they are indexed
in multiple languages. I added support for dynamic aliases (for
dynamic fields) so we can write
object:Blog.BlogPostClass AND property.Blog.BlogPostClass.title:text
AND object.XWiki.TagClass:news
and it will be expanded into
object:Blog.BlogPostClass AND
(property.Blog.BlogPostClass.title_en:text OR
property.Blog.BlogPostClass.title_fr:text OR ...) AND
(object.XWiki.TagClass_en:news OR object.XWiki.TagClass_fr:news OR
...)
NOTE: Solr doesn't support dynamic fields as default fields, i.e. as
fields that are matched when you search for free text (without
field:value in the query). This is not a problem for the search
results, as dynamic fields like object.* and property.* are copied and
aggregated in 'objcontent' which is a default field. The issue is that
we can't know what is exactly the XClass property that was matched, we
just know that the free search text was found inside an object.
WDYT? I can still make adjustments before 5.3 final if you think
something is wrong.
Thanks,
Marius
On Fri, Nov 15, 2013 at 9:01 AM, Paul Libbrecht <paul(a)hoplahup.net> wrote:
Hello Marius,
No for most cases.
A Lucene index is "just" a heap of "terms".
If you change the schema in that you add a new field, the impact on the index is zero.
If you rename a field, you need to reindex.
If you change the type of a field (or its analyzer) then you have to reindex.
If you delete a field, you leave some dirt, you'd have to reindex if you rewake this
field name.
I am not sure it's best practice, but as an application developer, I would enjoy if
this code was in a Groovy page.
paul
_______________________________________________
devs mailing list
devs(a)xwiki.org
http://lists.xwiki.org/mailman/listinfo/devs
I would
suggest to generate the schema and config, reloading every time there's a class
change.
That would mean re-indexing everything right? It would take to much time. I believe
that the query-expansion step, from title:x to title-en:x title-ft:x, etc… is best to be
controlled early so that applications can change that somehow. In curriki, this is done
with a custom query-component which uses the query-parser (with a default-field which does
not exist) then rewrites the query objects (which is a fairly easy game).
That's actually what I'm currently investigating. I'll try to extend
the ExtendedDismaxQParserPlugin, let it do its query parsing and then
expand the query with more query objects when the "field" name matches
some pattern (e.g. property_*)
3945
days inactive
3993
days old
15 comments
6 participants
participants (6)
-
Eduard Moraru -
Guillaume Lerouge -
Ludovic Dubost -
Marius Dumitru Florea -
Paul Libbrecht -
Thomas Mortagne