[Mondrian] xmla over olap4j server

[Michele Rossi]

Hi,
first all of thanks a lot for all your efforts on Mondrian and OLAP4J -
we're using both and they are working fantastically for us.

We have built our own OLAP4J driver for our internal system and we'd like to
use the feature described here by Julian Hyde:
http://julianhyde.blogspot.com/2010/...mondrians.html

What is the status of the work in this area?
I think that the ideal solution would be a webapp configurable with the
details of the OLAP4J driver / URL to connect to.

Unfortunately I am not at liberty to contribute to open source projects
during my working hours but I could think about doing it in my free time.

In that case we'd have a discussion about it and agree broadly on the
implementation.

What do you think about the above?

What perforce branch should I look at for those changes?
Is mondrian_release/3.2 the correct location?


thanks a lot,
Michele

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Julian Hyde]

Michele,

I have done about 90% of the work that you need, but the code is still part
of the mondrian code base. It would be great if you could push forward the
final 10%, and let me know what changes need to be made.

Then some point, I can spin all of this code (XmlaServlet, XmlaHandler) out
as a separate project that is outside the mondrian code base and has zero
dependencies on Mondrian. (I'd describe it as an "XMLA olap4j bridge"; not
to be confused with the XMLA olap4j driver, which operates in the reverse
direction.)

Later we might also move over mondrian's XMLA tests, packaging them in a jar
so that they can continue to be called from Mondrian's suite, but can also
be called from others' suites.

I did the changes on the //open/mondrian-release/3.2 branch (mainly changes
13929 and 13944, see below), but I have since integrated back to the main
line //open/mondrian. There aren't many differences between those branches
at this point, but you should work on main.

Perforce changes:

* 13929: http://perforce.eigenbase.org:8080/@md=d
<http://perforce.eigenbase.org:8080/@...g@/13929?ac=10
> &cd=//&rc=s&rg=c&c=Umg@/13929?ac=10
* 13944: http://perforce.eigenbase.org:8080/@md=d
<http://perforce.eigenbase.org:8080/@...g@/13944?ac=10
> &cd=//&rc=s&rg=c&c=Umg@/13944?ac=10

You would need to instantiate mondrian.xmla.impl.XmlaServlet (probably its
default implementation mondrian.xmla.impl.DefaultXmlaServlet) in your web
server.

You will see that XmlaServlet has a 'MondrianServer server' data member. But
it is only used to create an XmlaHandler, so you could easily remove it.

mondrian.xmla.XmlaHandler does most of the work, and following change 13929
and 13944 the dependencies on mondrian are minimal. Just utility classes. It
gets all of the information it needs from an olap4j connection.

The XmlaHandler.XmlaExtra interface provides extra metadata & functionality
that is not (currently) in the olap4j interface, such as drillthrough, and
whether a hierarchy is a parent-child hierarchy. Your olap4j connection
class can optionally provide an XmlaExtra, by implementing the
Connection.unwrap(Class) method. (Called from
XmlaHandler.getExtra(OlapConnection). If it returns null, XmlaHandler will
use a default XmlaExtra that uses dumb defaults.

The key callback is XmlaHandler.ConnectionFactory. Either provide
ConnectionFactory when servlet creates an XmlaHandler, or override
XmlaHandler.createConnection.

Your implementation of ConnectionFactory probably just creates an olap4j
connection, but it needs to set its catalog, schema and role consistent with
the values in the XMLA request.

Then XmlaHandler will call your olap4j connection to find other available
catalogs and schemas in that server.

I've punted on authentication for now. I assume that the container has
authenticated, and has set the "role_name" property in the request contet.
Probably if there is a username and password in the XMLA request they should
be passed into the getConnection method, but the olap4j provider should also
be able initiate request-response authentication over HTTP. And it should
figure out for itself the default role for that user. Much to do in that
area...

Hope that helps.

Julian


_____

From: mondrian-bounces (AT) pentaho (DOT) org [mailto:mondrian-bounces (AT) pentaho (DOT) org] On
Behalf Of Michele Rossi
Sent: Thursday, March 03, 2011 12:46 AM
To: mondrian (AT) pentaho (DOT) org
Subject: [Mondrian] xmla over olap4j server


Hi,
first all of thanks a lot for all your efforts on Mondrian and OLAP4J -
we're using both and they are working fantastically for us.

We have built our own OLAP4J driver for our internal system and we'd like to
use the feature described here by Julian Hyde:
http://julianhyde.blogspot.com/2010/...g-in-mondrians.
html

What is the status of the work in this area?
I think that the ideal solution would be a webapp configurable with the
details of the OLAP4J driver / URL to connect to.

Unfortunately I am not at liberty to contribute to open source projects
during my working hours but I could think about doing it in my free time.

In that case we'd have a discussion about it and agree broadly on the
implementation.

What do you think about the above?

What perforce branch should I look at for those changes?
Is mondrian_release/3.2 the correct location?


thanks a lot,
Michele


_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Michele Rossi]

Hi Julian,
regarding the new xmla server project - I have only ever created web-apps
(.WAR) using eclipse-level projects mirroring the folder
structure dictated by the servlet specification.

So you have a WEB-INF folder with a web.xml etc.

With such a layout Maven can create a WAR very easily.

I am sure that with Ant you can do all sorts of things, including creating
that structure dynamically with a bit of build.xml tricks.
However I am not sure about the best patterns to follow if we go down that
road.
The end product is a standard WAR file that you can run in any servlet
container and point to any olap4j driver right?


Patch files: sure, I assume it's something that the Perforce client can do
basing them on a changelist?
I will look into it.

Use of Maven: building a convincing case will take me a while and I am not
sure a long email is the best way to share my points.

I recently gave a presentation at work about it and people were quite
convinced afterwards.

Let's just say that if you adopt Maven you get all sorts of good things for
free including
-full eclipse integration

-automatic project-site generation with a variety of code quality reports
(test coverage is the one that impressed my boss most),

-integration with Sonar (another advanced code quality analysis tool)

-integration with TeamCity (automatic builds and test execution)

-entirely declarative build files ("pom.xml") with no strange tricks - much
easier to mantain than ANT scripts (it's a personal opinion of course but I
think those build.xml files are evil - they seem easy to write and later you
find them totally impossible to maintain / debug)


Michele

On 11 March 2011 18:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:

>
>
> ------------------------------
> *From:* Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
> *Sent:* Friday, March 11, 2011 1:43 AM
> *To:* mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
> *Subject:* Re: [Mondrian] xmla over olap4j server
>
> [re-sending from my private email address as it's not working from my work
> address]
>
>
>> Julian,
>> I have a few questions for you:
>>
>> 1. How do I get started?
>> Can you create an account on perforce for me with write permissions?
>>
> Please submit your changes as patches attached to jira cases. We don't give
> people committer privileges until they have made a few successful
> contributions.
>
> 2. Olap4j drillthrough
>> The mondrian olap4j driver implements drillthrough via the "executeQuery"
>> method which returns a java.sql.ResultSet right?
>> Can we not leverage that method to implement drillthrough on the xmla
>> server?
>>
> Possibly. Depends on your requirements. Mondrian's XMLA clients expect more
> in the XMLA response than is currently available in the ResultSet returned
> by that method. Therefore the XMLA server calls a method in XmlaExtra. The
> default implementation of XmlaExtra calls executeQuery. Same effect, longer
> route.
>
>
>>
>
>> 3. The new project:
>> We will need a new "olap4j xmla server" project with its separate build an
>> dependencies.
>> Can you think of a good name for it?
>> Perhaps Olap4jXmlaServer could be a good candidate
>>
> Sounds reasonable.
>
> 4. How to build the new project:
>> I know that mondrian is built using Ant.
>>
>> Have you ever thought about starting to use Maven?
>> I've used Maven successfully for years and I've totally forgot how to use
>> ant.
>>
>> I think it would also be beneficial in terms of linking olap4j releases
>> with server releases.
>> We could then distribute both olap4j, mondrian and the xmla server on
>> public maven repositories.
>>
> At this point I don't want to create a new project. I would like to work
> with the xmla server code in situ in the mondrian code base, to learn what
> the necessary changes are, and where would be the appropriate cut points.
> Then I will help you factor it into another project. But first, let's get it
> working in situ.
>
> Re. maven, see below.
>
>
>> 5. Proposed solution
>> I can put together a webapp project quickly using the following
>> ingredients
>>
>> a. maven build
>>
>> b. unit tests based on mondrian:
>> You create an in-process mondrian instance and connect to it using the
>> mondrian olap4j driver.
>> Then you hit the new server using the olap4j xmla driver.
>> You can then compare results making assertions on the equality of metadata
>> and values.
>>
>> c. The output artifact would a standard .WAR file
>>
>> d. Jetty launcher
>> I propose the creation of a jetty launcher too.
>> I can create such launcher using maven reasonably quickly.
>> The result would be a tar.gz file with a number of sub-folders, one of
>> them containing the .war file discussed above, others containing shared
>> jetty libraries and finally the .bat and .sh launchers.
>>
>> We could then have a "cfg" folder with a template .properties file where a
>> user would have to put the details of his/her favourite olap4j driver and
>> the connection details.
>>
> All of the above sounds fine. In due course. But please, don't make big
> changes as the first step. (I've found that the most successful committers
> are the ones who submit small patches at first.)
>
> In this case, the patches would be whatever hacks to mondrian's xmla server
> are necessary to build your flavor of the server. I will learn a lot from
> those patches.
>
> When time comes to create the new project, we can discuss using maven.
> You'd have to make a strong case, because it would be a Pentaho project
> (containing about 15k of mondrian source code, plus unit tests) and Pentaho
> projects have standardized on using an ant+ivy+subfloor infrastructure.
>
> Julian
>

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Julian Hyde]

Let's keep it simple. The output of this project should be a library (a jar
file), and one of the classes in that jar is a servlet. When the project is
built it will push the jar into pentaho's repository, which is
maven2-compatible.

Anyone who wants to package that jar into a war can do so, but in their own
workspace. You can write your own maven project for that if you wish.

Right now that jar would consist of a subset of the classes in
mondrian/classes. It's easy to build that jar by adding a few lines to
mondrian's build.xml, or even using 'jar -cvf' on the command line.

Julian


_____

From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
Sent: Friday, March 11, 2011 12:55 PM
To: jhyde (AT) pentaho (DOT) com
Cc: mondrian (AT) pentaho (DOT) org
Subject: Re: [Mondrian] xmla over olap4j server


Hi Julian,
regarding the new xmla server project - I have only ever created web-apps
(.WAR) using eclipse-level projects mirroring the folder structure dictated
by the servlet specification.

So you have a WEB-INF folder with a web.xml etc.

With such a layout Maven can create a WAR very easily.

I am sure that with Ant you can do all sorts of things, including creating
that structure dynamically with a bit of build.xml tricks.
However I am not sure about the best patterns to follow if we go down that
road.
The end product is a standard WAR file that you can run in any servlet
container and point to any olap4j driver right?


Patch files: sure, I assume it's something that the Perforce client can do
basing them on a changelist?
I will look into it.

Use of Maven: building a convincing case will take me a while and I am not
sure a long email is the best way to share my points.

I recently gave a presentation at work about it and people were quite
convinced afterwards.

Let's just say that if you adopt Maven you get all sorts of good things for
free including
-full eclipse integration

-automatic project-site generation with a variety of code quality reports
(test coverage is the one that impressed my boss most),

-integration with Sonar (another advanced code quality analysis tool)

-integration with TeamCity (automatic builds and test execution)

-entirely declarative build files ("pom.xml") with no strange tricks - much
easier to mantain than ANT scripts (it's a personal opinion of course but I
think those build.xml files are evil - they seem easy to write and later you
find them totally impossible to maintain / debug)


Michele


On 11 March 2011 18:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:





_____

From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
Sent: Friday, March 11, 2011 1:43 AM
To: mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
Subject: Re: [Mondrian] xmla over olap4j server


[re-sending from my private email address as it's not working from my work
address]



Julian,
I have a few questions for you:

1. How do I get started?
Can you create an account on perforce for me with write permissions?

Please submit your changes as patches attached to jira cases. We don't give
people committer privileges until they have made a few successful
contributions.

2. Olap4j drillthrough
The mondrian olap4j driver implements drillthrough via the "executeQuery"
method which returns a java.sql.ResultSet right?
Can we not leverage that method to implement drillthrough on the xmla
server?

Possibly. Depends on your requirements. Mondrian's XMLA clients expect more
in the XMLA response than is currently available in the ResultSet returned
by that method. Therefore the XMLA server calls a method in XmlaExtra. The
default implementation of XmlaExtra calls executeQuery. Same effect, longer
route.






3. The new project:
We will need a new "olap4j xmla server" project with its separate build an
dependencies.
Can you think of a good name for it?
Perhaps Olap4jXmlaServer could be a good candidate

Sounds reasonable.

4. How to build the new project:
I know that mondrian is built using Ant.


Have you ever thought about starting to use Maven?
I've used Maven successfully for years and I've totally forgot how to use
ant.


I think it would also be beneficial in terms of linking olap4j releases with
server releases.
We could then distribute both olap4j, mondrian and the xmla server on public
maven repositories.

At this point I don't want to create a new project. I would like to work
with the xmla server code in situ in the mondrian code base, to learn what
the necessary changes are, and where would be the appropriate cut points.
Then I will help you factor it into another project. But first, let's get it
working in situ.

Re. maven, see below.




5. Proposed solution
I can put together a webapp project quickly using the following ingredients


a. maven build


b. unit tests based on mondrian:
You create an in-process mondrian instance and connect to it using the
mondrian olap4j driver.
Then you hit the new server using the olap4j xmla driver.
You can then compare results making assertions on the equality of metadata
and values.


c. The output artifact would a standard .WAR file


d. Jetty launcher
I propose the creation of a jetty launcher too.
I can create such launcher using maven reasonably quickly.
The result would be a tar.gz file with a number of sub-folders, one of them
containing the .war file discussed above, others containing shared jetty
libraries and finally the .bat and .sh launchers.


We could then have a "cfg" folder with a template .properties file where a
user would have to put the details of his/her favourite olap4j driver and
the connection details.

All of the above sounds fine. In due course. But please, don't make big
changes as the first step. (I've found that the most successful committers
are the ones who submit small patches at first.)

In this case, the patches would be whatever hacks to mondrian's xmla server
are necessary to build your flavor of the server. I will learn a lot from
those patches.

When time comes to create the new project, we can discuss using maven. You'd
have to make a strong case, because it would be a Pentaho project
(containing about 15k of mondrian source code, plus unit tests) and Pentaho
projects have standardized on using an ant+ivy+subfloor infrastructure.


Julian



_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Michele Rossi]

hi,
sure it all sounds fine.
So the main piece of work here will be cutting out many dependencies of the
existing xmla servlet to the rest of the mondrian codebase.

I will have a go at it soon - no doubt I'll be in touch with more questions
once I get started.

thanks,
Michele


On 11 March 2011 22:12, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:

> Let's keep it simple. The output of this project should be a library (a
> jar file), and one of the classes in that jar is a servlet. When the project
> is built it will push the jar into pentaho's repository, which is
> maven2-compatible.
>
> Anyone who wants to package that jar into a war can do so, but in their own
> workspace. You can write your own maven project for that if you wish.
>
> Right now that jar would consist of a subset of the classes in
> mondrian/classes. It's easy to build that jar by adding a few lines to
> mondrian's build.xml, or even using 'jar -cvf' on the command line.
>
> Julian
>
> ------------------------------
> *From:* Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
> *Sent:* Friday, March 11, 2011 12:55 PM
> *To:* jhyde (AT) pentaho (DOT) com
> *Cc:* mondrian (AT) pentaho (DOT) org
>
> *Subject:* Re: [Mondrian] xmla over olap4j server
>
> Hi Julian,
> regarding the new xmla server project - I have only ever created web-apps
> (.WAR) using eclipse-level projects mirroring the folder
> structure dictated by the servlet specification.
>
> So you have a WEB-INF folder with a web.xml etc.
>
> With such a layout Maven can create a WAR very easily.
>
> I am sure that with Ant you can do all sorts of things, including creating
> that structure dynamically with a bit of build.xml tricks.
> However I am not sure about the best patterns to follow if we go down that
> road.
> The end product is a standard WAR file that you can run in any servlet
> container and point to any olap4j driver right?
>
>
> Patch files: sure, I assume it's something that the Perforce client can do
> basing them on a changelist?
> I will look into it.
>
> Use of Maven: building a convincing case will take me a while and I am not
> sure a long email is the best way to share my points.
>
> I recently gave a presentation at work about it and people were quite
> convinced afterwards.
>
> Let's just say that if you adopt Maven you get all sorts of good things for
> free including
> -full eclipse integration
>
> -automatic project-site generation with a variety of code quality reports
> (test coverage is the one that impressed my boss most),
>
> -integration with Sonar (another advanced code quality analysis tool)
>
> -integration with TeamCity (automatic builds and test execution)
>
> -entirely declarative build files ("pom.xml") with no strange tricks - much
> easier to mantain than ANT scripts (it's a personal opinion of course but I
> think those build.xml files are evil - they seem easy to write and later you
> find them totally impossible to maintain / debug)
>
>
> Michele
>
> On 11 March 2011 18:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:
>
>>
>>
>> ------------------------------
>> *From:* Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
>> *Sent:* Friday, March 11, 2011 1:43 AM
>> *To:* mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
>> *Subject:* Re: [Mondrian] xmla over olap4j server
>>
>> [re-sending from my private email address as it's not working from my
>> work address]
>>
>>
>>> Julian,
>>> I have a few questions for you:
>>>
>>> 1. How do I get started?
>>> Can you create an account on perforce for me with write permissions?
>>>
>> Please submit your changes as patches attached to jira cases. We don't
>> give people committer privileges until they have made a few successful
>> contributions.
>>
>> 2. Olap4j drillthrough
>>> The mondrian olap4j driver implements drillthrough via the "executeQuery"
>>> method which returns a java.sql.ResultSet right?
>>> Can we not leverage that method to implement drillthrough on the xmla
>>> server?
>>>
>> Possibly. Depends on your requirements. Mondrian's XMLA clients expect
>> more in the XMLA response than is currently available in the ResultSet
>> returned by that method. Therefore the XMLA server calls a method in
>> XmlaExtra. The default implementation of XmlaExtra calls executeQuery. Same
>> effect, longer route.
>>
>>
>>>
>>
>>> 3. The new project:
>>> We will need a new "olap4j xmla server" project with its separate build
>>> an dependencies.
>>> Can you think of a good name for it?
>>> Perhaps Olap4jXmlaServer could be a good candidate
>>>
>> Sounds reasonable.
>>
>> 4. How to build the new project:
>>> I know that mondrian is built using Ant.
>>>
>>> Have you ever thought about starting to use Maven?
>>> I've used Maven successfully for years and I've totally forgot how to use
>>> ant.
>>>
>>> I think it would also be beneficial in terms of linking olap4j releases
>>> with server releases.
>>> We could then distribute both olap4j, mondrian and the xmla server on
>>> public maven repositories.
>>>
>> At this point I don't want to create a new project. I would like to work
>> with the xmla server code in situ in the mondrian code base, to learn what
>> the necessary changes are, and where would be the appropriate cut points.
>> Then I will help you factor it into another project. But first, let's get it
>> working in situ.
>>
>> Re. maven, see below.
>>
>>
>>> 5. Proposed solution
>>> I can put together a webapp project quickly using the following
>>> ingredients
>>>
>>> a. maven build
>>>
>>> b. unit tests based on mondrian:
>>> You create an in-process mondrian instance and connect to it using the
>>> mondrian olap4j driver.
>>> Then you hit the new server using the olap4j xmla driver.
>>> You can then compare results making assertions on the equality of
>>> metadata and values.
>>>
>>> c. The output artifact would a standard .WAR file
>>>
>>> d. Jetty launcher
>>> I propose the creation of a jetty launcher too.
>>> I can create such launcher using maven reasonably quickly.
>>> The result would be a tar.gz file with a number of sub-folders, one of
>>> them containing the .war file discussed above, others containing shared
>>> jetty libraries and finally the .bat and .sh launchers.
>>>
>>> We could then have a "cfg" folder with a template .properties file where
>>> a user would have to put the details of his/her favourite olap4j driver and
>>> the connection details.
>>>
>> All of the above sounds fine. In due course. But please, don't make big
>> changes as the first step. (I've found that the most successful committers
>> are the ones who submit small patches at first.)
>>
>> In this case, the patches would be whatever hacks to mondrian's xmla
>> server are necessary to build your flavor of the server. I will learn a lot
>> from those patches.
>>
>> When time comes to create the new project, we can discuss using maven.
>> You'd have to make a strong case, because it would be a Pentaho project
>> (containing about 15k of mondrian source code, plus unit tests) and Pentaho
>> projects have standardized on using an ant+ivy+subfloor infrastructure.
>>
>> Julian
>>
>
>

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[VanIngen, Erik (FIPS)]

Dear Mondrian,

I am about to integrate Mondrian in my SDMX project and I came across this message. I would vote for the use of Maven in the Mondrian project. The advantages are huge like little build configuration files (convention over configuration), excellent integration in IDE's and Continuous Integration servers and so on.

Erik

From: mondrian-bounces (AT) pentaho (DOT) org [mailto:mondrian-bounces (AT) pentaho (DOT) org] On Behalf Of Julian Hyde
Sent: 11 March 2011 22:13
To: 'Michele Rossi'
Cc: mondrian (AT) pentaho (DOT) org
Subject: RE: [Mondrian] xmla over olap4j server

Let's keep it simple. The output of this project should be a library (a jar file), and one of the classes in that jar is a servlet. When the project is built it will push the jar into pentaho's repository, which is maven2-compatible.

Anyone who wants to package that jar into a war can do so, but in their own workspace. You can write your own maven project for that if you wish.

Right now that jar would consist of a subset of the classes in mondrian/classes. It's easy to build that jar by adding a few lines to mondrian's build..xml, or even using 'jar -cvf' on the command line.

Julian

________________________________
From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
Sent: Friday, March 11, 2011 12:55 PM
To: jhyde (AT) pentaho (DOT) com
Cc: mondrian (AT) pentaho (DOT) org
Subject: Re: [Mondrian] xmla over olap4j server
Hi Julian,
regarding the new xmla server project - I have only ever created web-apps (..WAR) using eclipse-level projects mirroring the folder structure dictated by the servlet specification.

So you have a WEB-INF folder with a web.xml etc.

With such a layout Maven can create a WAR very easily.

I am sure that with Ant you can do all sorts of things, including creating that structure dynamically with a bit of build.xml tricks.
However I am not sure about the best patterns to follow if we go down that road.
The end product is a standard WAR file that you can run in any servlet container and point to any olap4j driver right?


Patch files: sure, I assume it's something that the Perforce client can do basing them on a changelist?
I will look into it.

Use of Maven: building a convincing case will take me a while and I am not sure a long email is the best way to share my points.

I recently gave a presentation at work about it and people were quite convinced afterwards.

Let's just say that if you adopt Maven you get all sorts of good things for free including
-full eclipse integration

-automatic project-site generation with a variety of code quality reports (test coverage is the one that impressed my boss most),

-integration with Sonar (another advanced code quality analysis tool)

-integration with TeamCity (automatic builds and test execution)

-entirely declarative build files ("pom.xml") with no strange tricks - much easier to mantain than ANT scripts (it's a personal opinion of course but I think those build.xml files are evil - they seem easy to write and later you find them totally impossible to maintain / debug)


Michele
On 11 March 2011 18:56, Julian Hyde <jhyde (AT) pentaho (DOT) com<mailto:jhyde (AT) pentaho (DOT) .com>> wrote:


________________________________
From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com<mailto:michele.rossi (AT) gmail (DOT) com>]
Sent: Friday, March 11, 2011 1:43 AM
To: mondrian (AT) pentaho (DOT) org<mail...taho (DOT) org>; jhyde (AT) pentaho (DOT) com<mailto:...taho (DOT) com>
Subject: Re: [Mondrian] xmla over olap4j server
[re-sending from my private email address as it's not working from my work address]


Julian,
I have a few questions for you:

1. How do I get started?
Can you create an account on perforce for me with write permissions?
Please submit your changes as patches attached to jira cases. We don't give people committer privileges until they have made a few successful contributions.
2. Olap4j drillthrough
The mondrian olap4j driver implements drillthrough via the "executeQuery" method which returns a java.sql.ResultSet right?
Can we not leverage that method to implement drillthrough on the xmla server?
Possibly. Depends on your requirements. Mondrian's XMLA clients expect more in the XMLA response than is currently available in the ResultSet returned by that method. Therefore the XMLA server calls a method in XmlaExtra. The default implementation of XmlaExtra calls executeQuery. Same effect, longer route.


3. The new project:
We will need a new "olap4j xmla server" project with its separate build an dependencies.
Can you think of a good name for it?
Perhaps Olap4jXmlaServer could be a good candidate
Sounds reasonable.
4. How to build the new project:
I know that mondrian is built using Ant.

Have you ever thought about starting to use Maven?
I've used Maven successfully for years and I've totally forgot how to use ant.

I think it would also be beneficial in terms of linking olap4j releases with server releases.
We could then distribute both olap4j, mondrian and the xmla server on public maven repositories.
At this point I don't want to create a new project. I would like to work with the xmla server code in situ in the mondrian code base, to learn what the necessary changes are, and where would be the appropriate cut points. Then I will help you factor it into another project. But first, let's get it working in situ.

Re. maven, see below.

5. Proposed solution
I can put together a webapp project quickly using the following ingredients

a. maven build

b. unit tests based on mondrian:
You create an in-process mondrian instance and connect to it using the mondrian olap4j driver.
Then you hit the new server using the olap4j xmla driver.
You can then compare results making assertions on the equality of metadata and values.

c. The output artifact would a standard .WAR file

d. Jetty launcher
I propose the creation of a jetty launcher too.
I can create such launcher using maven reasonably quickly.
The result would be a tar.gz file with a number of sub-folders, one of them containing the .war file discussed above, others containing shared jetty libraries and finally the .bat and .sh launchers.

We could then have a "cfg" folder with a template .properties file where a user would have to put the details of his/her favourite olap4j driver and the connection details.
All of the above sounds fine. In due course. But please, don't make big changes as the first step. (I've found that the most successful committers are the ones who submit small patches at first.)

In this case, the patches would be whatever hacks to mondrian's xmla server are necessary to build your flavor of the server. I will learn a lot from those patches.

When time comes to create the new project, we can discuss using maven. You'd have to make a strong case, because it would be a Pentaho project (containing about 15k of mondrian source code, plus unit tests) and Pentaho projects have standardized on using an ant+ivy+subfloor infrastructure.

Julian


_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Tom Barber]

As pointed out, pentaho has a Maven/Ivy repo to build projects with Mondrian in them, unless you need the source and build that, you can pull the latest and stable builds from repo.pentaho.org (login guest:guest).

Tom
________________________________________
From: mondrian-bounces (AT) pentaho (DOT) org [mondrian-bounces (AT) pentaho (DOT) org] On Behalf Of VanIngen, Erik (FIPS) [Erik.VanIngen (AT) fao (DOT) org]
Sent: 14 March 2011 14:33
To: jhyde (AT) pentaho (DOT) com; Mondrian developer mailing list; 'Michele Rossi'
Subject: RE: [Mondrian] xmla over olap4j server

Dear Mondrian,

I am about to integrate Mondrian in my SDMX project and I came across this message. I would vote for the use of Maven in the Mondrian project. The advantages are huge like little build configuration files (convention over configuration), excellent integration in IDE

[Julian Hyde]

Erik VanIngen wrote:

I am about to integrate Mondrian in my SDMX project and I came across this
message. I would vote for the use of Maven in the Mondrian project. The
advantages are huge like little build configuration files (convention over
configuration), excellent integration in IDE's and Continuous Integration
servers and so on.

Best I can say is the following. I have noted the enthusiasm for Maven in
our community. We will consider Maven as an option next time there is a need
& opportunity to change our build system. For now, our build system works,
doesn't require a lot of maintenance, and does a lot of useful stuff that we
don't want to have to re-build.

Meantime, as Tom also pointed out, Maven projects can use Mondrian and
olap4j (and other Pentaho libraries) because we deploy components to a
Maven-compatible repository.

Julian

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[VanIngen, Erik (FIPS)]

Hi Mondrian,

I am prototyping with a system that will generate SDMX from Mondrian. As in input it will probably use the RolapSchemes.

Therefore a few questions:

(1) Is there a Java binding available for this xsd /mondrian-src/mondrian-3.2.1.13885/lib/mondrian.xsd ? If not, how is a RolapScheme un-marshalled in Mondrian?

(2) When publishing the RolapScheme in Mondrian, is it available through an URL?

(3) Is Mondrian publishing the list of Rolapschemes as a webservice?

Cheers,
Erik




_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Michele Rossi]

[ re sending to the whole list as requested by Julian ]

Hi Julian,
I've completed the first stage of the xmla-over-olap4j work.

I still haven't found out how to create patch files - it can probably be
done using the p4 client, I will look at it tomorrow.

For now I am attaching to this email the three files that I updated and an
example web.xml that shows how the servlet could be deployed.
You can find most of my changes easily by searching for [MROSSI].

Initially I tried to split out the servlet from the rest of the Mondrian
codebase but the dependencies are many and go fairly deep.
I am not sure that such an endeavour would be very valuable.
After all there is nothing wrong in just using the whole mondrian jar as it
is.

I've tested my code using Excel and the SimbaO2X adapter.
I can successfully connect to a Foodmart olap database in the following way:

Excel-->Simba-->My Server with the modified DefaultXmlaServlet-->Olap4j Xmla
Driver-->A standard mondrian installation with a standard xmla servlet.

I will need to make some more changes to handle the credentials passed by
Excel in the XMLA requests.
I did most of the work last year but never contributed it back.

What do you think?
How do you think I should proceed from this point?

Many thanks!
Michele



On 11 March 2011 17:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:

>
>
> ------------------------------
> *From:* Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
> *Sent:* Friday, March 11, 2011 1:43 AM
> *To:* mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
> *Subject:* Re: [Mondrian] xmla over olap4j server
>
> [re-sending from my private email address as it's not working from my work
> address]
>
>
>> Julian,
>> I have a few questions for you:
>>
>> 1. How do I get started?
>> Can you create an account on perforce for me with write permissions?
>>
> Please submit your changes as patches attached to jira cases. We don't give
> people committer privileges until they have made a few successful
> contributions.
>
> 2. Olap4j drillthrough
>> The mondrian olap4j driver implements drillthrough via the "executeQuery"
>> method which returns a java.sql.ResultSet right?
>> Can we not leverage that method to implement drillthrough on the xmla
>> server?
>>
> Possibly. Depends on your requirements. Mondrian's XMLA clients expect more
> in the XMLA response than is currently available in the ResultSet returned
> by that method. Therefore the XMLA server calls a method in XmlaExtra. The
> default implementation of XmlaExtra calls executeQuery. Same effect, longer
> route.
>
>
>>
>
>> 3. The new project:
>> We will need a new "olap4j xmla server" project with its separate build an
>> dependencies.
>> Can you think of a good name for it?
>> Perhaps Olap4jXmlaServer could be a good candidate
>>
> Sounds reasonable.
>
> 4. How to build the new project:
>> I know that mondrian is built using Ant.
>>
>> Have you ever thought about starting to use Maven?
>> I've used Maven successfully for years and I've totally forgot how to use
>> ant.
>>
>> I think it would also be beneficial in terms of linking olap4j releases
>> with server releases.
>> We could then distribute both olap4j, mondrian and the xmla server on
>> public maven repositories.
>>
> At this point I don't want to create a new project. I would like to work
> with the xmla server code in situ in the mondrian code base, to learn what
> the necessary changes are, and where would be the appropriate cut points.
> Then I will help you factor it into another project. But first, let's get it
> working in situ.
>
> Re. maven, see below.
>
>
>> 5. Proposed solution
>> I can put together a webapp project quickly using the following
>> ingredients
>>
>> a. maven build
>>
>> b. unit tests based on mondrian:
>> You create an in-process mondrian instance and connect to it using the
>> mondrian olap4j driver.
>> Then you hit the new server using the olap4j xmla driver.
>> You can then compare results making assertions on the equality of metadata
>> and values.
>>
>> c. The output artifact would a standard .WAR file
>>
>> d. Jetty launcher
>> I propose the creation of a jetty launcher too.
>> I can create such launcher using maven reasonably quickly.
>> The result would be a tar.gz file with a number of sub-folders, one of
>> them containing the .war file discussed above, others containing shared
>> jetty libraries and finally the .bat and .sh launchers.
>>
>> We could then have a "cfg" folder with a template .properties file where a
>> user would have to put the details of his/her favourite olap4j driver and
>> the connection details.
>>
> All of the above sounds fine. In due course. But please, don't make big
> changes as the first step. (I've found that the most successful committers
> are the ones who submit small patches at first.)
>
> In this case, the patches would be whatever hacks to mondrian's xmla server
> are necessary to build your flavor of the server. I will learn a lot from
> those patches.
>
> When time comes to create the new project, we can discuss using maven.
> You'd have to make a strong case, because it would be a Pentaho project
> (containing about 15k of mondrian source code, plus unit tests) and Pentaho
> projects have standardized on using an ant+ivy+subfloor infrastructure.
>
> Julian
>

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Julian Hyde]

Michele,

I have checked in your changes as change 14208. I moved things around a bit
-- I moved your olap4j connection factory out of XmlaServlet into a new
derived class, Olap4jXmlaServlet. And the previous functionality, to start
an embedded mondrian server, is in a new subclass MondrianXmlaServlet.

I hope that I have preserved the intent of your changes.

Thanks for the contribution. It definitely moves us down the road to an XMLA
server that is independent of mondrian.

Other users (including Pentaho BI server team), take note: Applications that
used DefaultXmlaServlet should probably now use MondrianXmlaServlet.

Julian


_____

From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
Sent: Friday, April 15, 2011 1:36 AM
To: Mondrian developer mailing list
Cc: jhyde (AT) pentaho (DOT) com
Subject: Re: [Mondrian] xmla over olap4j server


[ re sending to the whole list as requested by Julian ]

Hi Julian,
I've completed the first stage of the xmla-over-olap4j work.

I still haven't found out how to create patch files - it can probably be
done using the p4 client, I will look at it tomorrow.

For now I am attaching to this email the three files that I updated and an
example web.xml that shows how the servlet could be deployed.
You can find most of my changes easily by searching for [MROSSI].

Initially I tried to split out the servlet from the rest of the Mondrian
codebase but the dependencies are many and go fairly deep.
I am not sure that such an endeavour would be very valuable.
After all there is nothing wrong in just using the whole mondrian jar as it
is.

I've tested my code using Excel and the SimbaO2X adapter.
I can successfully connect to a Foodmart olap database in the following way:

Excel-->Simba-->My Server with the modified DefaultXmlaServlet-->Olap4j Xmla
Driver-->A standard mondrian installation with a standard xmla servlet.

I will need to make some more changes to handle the credentials passed by
Excel in the XMLA requests.
I did most of the work last year but never contributed it back.

What do you think?
How do you think I should proceed from this point?

Many thanks!
Michele



On 11 March 2011 17:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:





_____

From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
Sent: Friday, March 11, 2011 1:43 AM
To: mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
Subject: Re: [Mondrian] xmla over olap4j server


[re-sending from my private email address as it's not working from my work
address]



Julian,
I have a few questions for you:

1. How do I get started?
Can you create an account on perforce for me with write permissions?

Please submit your changes as patches attached to jira cases. We don't give
people committer privileges until they have made a few successful
contributions.

2. Olap4j drillthrough
The mondrian olap4j driver implements drillthrough via the "executeQuery"
method which returns a java.sql.ResultSet right?
Can we not leverage that method to implement drillthrough on the xmla
server?

Possibly. Depends on your requirements. Mondrian's XMLA clients expect more
in the XMLA response than is currently available in the ResultSet returned
by that method. Therefore the XMLA server calls a method in XmlaExtra. The
default implementation of XmlaExtra calls executeQuery. Same effect, longer
route.






3. The new project:
We will need a new "olap4j xmla server" project with its separate build an
dependencies.
Can you think of a good name for it?
Perhaps Olap4jXmlaServer could be a good candidate

Sounds reasonable.

4. How to build the new project:
I know that mondrian is built using Ant.


Have you ever thought about starting to use Maven?
I've used Maven successfully for years and I've totally forgot how to use
ant.


I think it would also be beneficial in terms of linking olap4j releases with
server releases.
We could then distribute both olap4j, mondrian and the xmla server on public
maven repositories.

At this point I don't want to create a new project. I would like to work
with the xmla server code in situ in the mondrian code base, to learn what
the necessary changes are, and where would be the appropriate cut points.
Then I will help you factor it into another project. But first, let's get it
working in situ.

Re. maven, see below.




5. Proposed solution
I can put together a webapp project quickly using the following ingredients


a. maven build


b. unit tests based on mondrian:
You create an in-process mondrian instance and connect to it using the
mondrian olap4j driver.
Then you hit the new server using the olap4j xmla driver.
You can then compare results making assertions on the equality of metadata
and values.


c. The output artifact would a standard .WAR file


d. Jetty launcher
I propose the creation of a jetty launcher too.
I can create such launcher using maven reasonably quickly.
The result would be a tar.gz file with a number of sub-folders, one of them
containing the .war file discussed above, others containing shared jetty
libraries and finally the .bat and .sh launchers.


We could then have a "cfg" folder with a template .properties file where a
user would have to put the details of his/her favourite olap4j driver and
the connection details.

All of the above sounds fine. In due course. But please, don't make big
changes as the first step. (I've found that the most successful committers
are the ones who submit small patches at first.)

In this case, the patches would be whatever hacks to mondrian's xmla server
are necessary to build your flavor of the server. I will learn a lot from
those patches.

When time comes to create the new project, we can discuss using maven. You'd
have to make a strong case, because it would be a Pentaho project
(containing about 15k of mondrian source code, plus unit tests) and Pentaho
projects have standardized on using an ant+ivy+subfloor infrastructure.


Julian




_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Andy Grohe]

What are the advantages of splitting out xmla from Mondrian to the community? At this time, they seem linked in my mind.

Sent from my iPhone

On Apr 18, 2011, at 11:20 PM, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:

> Michele,
>
> I have checked in your changes as change 14208. I moved things around a bit -- I moved your olap4j connection factory out of XmlaServlet into a new derived class, Olap4jXmlaServlet. And the previous functionality, to start an embedded mondrian server, is in a new subclass MondrianXmlaServlet.
>
> I hope that I have preserved the intent of your changes.
>
> Thanks for the contribution. It definitely moves us down the road to an XMLA server that is independent of mondrian.
>
> Other users (including Pentaho BI server team), take note: Applications that used DefaultXmlaServlet should probably now use MondrianXmlaServlet.
>
> Julian
>
> From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
> Sent: Friday, April 15, 2011 1:36 AM
> To: Mondrian developer mailing list
> Cc: jhyde (AT) pentaho (DOT) com
> Subject: Re: [Mondrian] xmla over olap4j server
>
> [ re sending to the whole list as requested by Julian ]
>
> Hi Julian,
> I've completed the first stage of the xmla-over-olap4j work.
>
> I still haven't found out how to create patch files - it can probably be done using the p4 client, I will look at it tomorrow.
>
> For now I am attaching to this email the three files that I updated and an example web.xml that shows how the servlet could be deployed.
> You can find most of my changes easily by searching for [MROSSI].
>
> Initially I tried to split out the servlet from the rest of the Mondrian codebase but the dependencies are many and go fairly deep.
> I am not sure that such an endeavour would be very valuable.
> After all there is nothing wrong in just using the whole mondrian jar as it is.
>
> I've tested my code using Excel and the SimbaO2X adapter.
> I can successfully connect to a Foodmart olap database in the following way:
>
> Excel-->Simba-->My Server with the modified DefaultXmlaServlet-->Olap4j Xmla Driver-->A standard mondrian installation with a standard xmla servlet.
>
> I will need to make some more changes to handle the credentials passed by Excel in the XMLA requests.
> I did most of the work last year but never contributed it back.
>
> What do you think?
> How do you think I should proceed from this point?
>
> Many thanks!
> Michele
>
>
>
> On 11 March 2011 17:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:
>
>
> From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
> Sent: Friday, March 11, 2011 1:43 AM
> To: mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
> Subject: Re: [Mondrian] xmla over olap4j server
>
> [re-sending from my private email address as it's not working from my work address]
>
>
> Julian,
> I have a few questions for you:
>
> 1. How do I get started?
> Can you create an account on perforce for me with write permissions?
> Please submit your changes as patches attached to jira cases. We don't give people committer privileges until they have made a few successful contributions.
> 2. Olap4j drillthrough
> The mondrian olap4j driver implements drillthrough via the "executeQuery" method which returns a java.sql.ResultSet right?
> Can we not leverage that method to implement drillthrough on the xmla server?
> Possibly. Depends on your requirements. Mondrian's XMLA clients expect more in the XMLA response than is currently available in the ResultSet returned by that method. Therefore the XMLA server calls a method in XmlaExtra. The default implementation of XmlaExtra calls executeQuery. Same effect, longer route.
>
>
> 3. The new project:
> We will need a new "olap4j xmla server" project with its separate build an dependencies.
> Can you think of a good name for it?
> Perhaps Olap4jXmlaServer could be a good candidate
> Sounds reasonable.
> 4. How to build the new project:
> I know that mondrian is built using Ant.
>
> Have you ever thought about starting to use Maven?
> I've used Maven successfully for years and I've totally forgot how to use ant.
>
> I think it would also be beneficial in terms of linking olap4j releases with server releases.
> We could then distribute both olap4j, mondrian and the xmla server on public maven repositories.
> At this point I don't want to create a new project. I would like to work with the xmla server code in situ in the mondrian code base, to learn what the necessary changes are, and where would be the appropriate cut points. Then I will help you factor it into another project. But first, let's get it working in situ.
>
> Re. maven, see below.
>
> 5. Proposed solution
> I can put together a webapp project quickly using the following ingredients
>
> a. maven build
>
> b. unit tests based on mondrian:
> You create an in-process mondrian instance and connect to it using the mondrian olap4j driver.
> Then you hit the new server using the olap4j xmla driver.
> You can then compare results making assertions on the equality of metadata and values.
>
> c. The output artifact would a standard .WAR file
>
> d. Jetty launcher
> I propose the creation of a jetty launcher too.
> I can create such launcher using maven reasonably quickly.
> The result would be a tar.gz file with a number of sub-folders, one of them containing the .war file discussed above, others containing shared jetty libraries and finally the .bat and .sh launchers.
>
> We could then have a "cfg" folder with a template .properties file where a user would have to put the details of his/her favourite olap4j driver and the connection details.
> All of the above sounds fine. In due course. But please, don't make big changes as the first step. (I've found that the most successful committers are the ones who submit small patches at first.)
>
> In this case, the patches would be whatever hacks to mondrian's xmla server are necessary to build your flavor of the server. I will learn a lot from those patches.
>
> When time comes to create the new project, we can discuss using maven. You'd have to make a strong case, because it would be a Pentaho project (containing about 15k of mondrian source code, plus unit tests) and Pentaho projects have standardized on using an ant+ivy+subfloor infrastructure.
>
> Julian
>
>
> _______________________________________________
> Mondrian mailing list
> Mondrian (AT) pentaho (DOT) org
> http://lists.pentaho.org/mailman/listinfo/mondrian

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Michele Rossi]

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Andy Grohe]

I think that states it clearly.

Now we just need more olap4j implementations that Mondrian.

So the xmla server requires an olap4j implementation in the engine side?

Thanks

Sent from my iPhone

On Apr 19, 2011, at 8:00 AM, Michele Rossi <m.rossi (AT) iontrading (DOT) com> wrote:

> hi,
> The xmla servlet is not actually being split from the mondrian codebase (at least for now).
> However its functionality is very distinct from Mondrian and refactoring the two functional areas is a matter of clean design and separation of concerns.
>
> Having an XMLA Servlet that can rely on a standard OLAP4J driver instead of the native mondrian API will allow other OLAP engines that have an OLAP4J driver to be exposed via XMLA.
>
> Another angle on this is that until now mondrian has been both a server (xmla) and an aggregation engine.
> The idea is to split the two things.
> Mondrian can keep being an engine, and the XMLA Servlet allows anyone with an OLAP driver to become an OLAP Server.
>
> Julian can probably put it in a better way.
>
> thanks,
> Michele
>
>
>
>
> On 19 April 2011 14:17, Andy Grohe <agrohe21 (AT) gmail (DOT) com> wrote:
> What are the advantages of splitting out xmla from Mondrian to the community? At this time, they seem linked in my mind.
>
> Sent from my iPhone
>
> On Apr 18, 2011, at 11:20 PM, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:
>
>> Michele,
>>
>> I have checked in your changes as change 14208. I moved things around a bit -- I moved your olap4j connection factory out of XmlaServlet into a new derived class, Olap4jXmlaServlet. And the previous functionality, to start an embedded mondrian server, is in a new subclass MondrianXmlaServlet.
>>
>> I hope that I have preserved the intent of your changes.
>>
>> Thanks for the contribution. It definitely moves us down the road to an XMLA server that is independent of mondrian.
>>
>> Other users (including Pentaho BI server team), take note: Applications that used DefaultXmlaServlet should probably now use MondrianXmlaServlet.
>>
>> Julian
>>
>> From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
>> Sent: Friday, April 15, 2011 1:36 AM
>> To: Mondrian developer mailing list
>> Cc: jhyde (AT) pentaho (DOT) com
>> Subject: Re: [Mondrian] xmla over olap4j server
>>
>> [ re sending to the whole list as requested by Julian ]
>>
>> Hi Julian,
>> I've completed the first stage of the xmla-over-olap4j work.
>>
>> I still haven't found out how to create patch files - it can probably be done using the p4 client, I will look at it tomorrow.
>>
>> For now I am attaching to this email the three files that I updated and an example web.xml that shows how the servlet could be deployed.
>> You can find most of my changes easily by searching for [MROSSI].
>>
>> Initially I tried to split out the servlet from the rest of the Mondrian codebase but the dependencies are many and go fairly deep.
>> I am not sure that such an endeavour would be very valuable.
>> After all there is nothing wrong in just using the whole mondrian jar as it is.
>>
>> I've tested my code using Excel and the SimbaO2X adapter.
>> I can successfully connect to a Foodmart olap database in the following way:
>>
>> Excel-->Simba-->My Server with the modified DefaultXmlaServlet-->Olap4j Xmla Driver-->A standard mondrian installation with a standard xmla servlet.
>>
>> I will need to make some more changes to handle the credentials passed by Excel in the XMLA requests.
>> I did most of the work last year but never contributed it back.
>>
>> What do you think?
>> How do you think I should proceed from this point?
>>
>> Many thanks!
>> Michele
>>
>>
>>
>> On 11 March 2011 17:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:
>>
>>
>> From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
>> Sent: Friday, March 11, 2011 1:43 AM
>> To: mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
>> Subject: Re: [Mondrian] xmla over olap4j server
>>
>> [re-sending from my private email address as it's not working from my work address]
>>
>>
>> Julian,
>> I have a few questions for you:
>>
>> 1. How do I get started?
>> Can you create an account on perforce for me with write permissions?
>> Please submit your changes as patches attached to jira cases. We don't give people committer privileges until they have made a few successful contributions.
>> 2. Olap4j drillthrough
>> The mondrian olap4j driver implements drillthrough via the "executeQuery" method which returns a java.sql.ResultSet right?
>> Can we not leverage that method to implement drillthrough on the xmla server?
>> Possibly. Depends on your requirements. Mondrian's XMLA clients expect more in the XMLA response than is currently available in the ResultSet returned by that method. Therefore the XMLA server calls a method in XmlaExtra. The default implementation of XmlaExtra calls executeQuery. Same effect, longer route.
>>
>>
>> 3. The new project:
>> We will need a new "olap4j xmla server" project with its separate build an dependencies.
>> Can you think of a good name for it?
>> Perhaps Olap4jXmlaServer could be a good candidate
>> Sounds reasonable.
>> 4. How to build the new project:
>> I know that mondrian is built using Ant.
>>
>> Have you ever thought about starting to use Maven?
>> I've used Maven successfully for years and I've totally forgot how to use ant.
>>
>> I think it would also be beneficial in terms of linking olap4j releases with server releases.
>> We could then distribute both olap4j, mondrian and the xmla server on public maven repositories.
>> At this point I don't want to create a new project. I would like to work with the xmla server code in situ in the mondrian code base, to learn what the necessary changes are, and where would be the appropriate cut points. Then I will help you factor it into another project. But first, let's get it working in situ.
>>
>> Re. maven, see below.
>>
>> 5. Proposed solution
>> I can put together a webapp project quickly using the following ingredients
>>
>> a. maven build
>>
>> b. unit tests based on mondrian:
>> You create an in-process mondrian instance and connect to it using the mondrian olap4j driver.
>> Then you hit the new server using the olap4j xmla driver.
>> You can then compare results making assertions on the equality of metadata and values.
>>
>> c. The output artifact would a standard .WAR file
>>
>> d. Jetty launcher
>> I propose the creation of a jetty launcher too.
>> I can create such launcher using maven reasonably quickly.
>> The result would be a tar.gz file with a number of sub-folders, one of them containing the .war file discussed above, others containing shared jetty libraries and finally the .bat and .sh launchers.
>>
>> We could then have a "cfg" folder with a template .properties file where a user would have to put the details of his/her favourite olap4j driver and the connection details.
>> All of the above sounds fine. In due course. But please, don't make big changes as the first step. (I've found that the most successful committers are the ones who submit small patches at first.)
>>
>> In this case, the patches would be whatever hacks to mondrian's xmla server are necessary to build your flavor of the server. I will learn a lot from those patches.
>>
>> When time comes to create the new project, we can discuss using maven. You'd have to make a strong case, because it would be a Pentaho project (containing about 15k of mondrian source code, plus unit tests) and Pentaho projects have standardized on using an ant+ivy+subfloor infrastructure.
>>
>> Julian
>>
>>
>> _______________________________________________
>> Mondrian mailing list
>> Mondrian (AT) pentaho (DOT) org
>> http://lists.pentaho.org/mailman/listinfo/mondrian
>
> _______________________________________________
> Mondrian mailing list
> Mondrian (AT) pentaho (DOT) org
> http://lists.pentaho.org/mailman/listinfo/mondrian
>
>
>
>
> --
>
>
> Michele Rossi
>
> <image001.jpg>
>
> Via San Martino, 52, 56125 Pisa, ITALY
> T: +39 050 220 3894
> m.rossi (AT) iontrading (DOT) com
> http://www.iontrading.com
>
>
> _______________________________________________
> Mondrian mailing list
> Mondrian (AT) pentaho (DOT) org
> http://lists.pentaho.org/mailman/listinfo/mondrian

_______________________________________________
Mondrian mailing list
Mondrian (AT) pentaho (DOT) org
http://lists.pentaho.org/mailman/listinfo/mondrian

[Michele Rossi]

_______________________________________________
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[Paul Stoellberger]

there will be a oracle olap driver at some point too. luc said its on his todo list.

but i'd rather use the olap4j api directly than exposing my olap4j as xmla. this is only beneficial if you have a nice existing xmla client that you want to use for accessing system.

i think julians point with this refactoring is to hide the mondrian api and making the olap4j api the only one that matters.
and as a nice side effect you get an xmla server for all olap4j compatible systems.

i would expect the xmla-servlet code to move to olap4j at some point.

paul


Am 19.04.2011 um 14:56 schrieb Michele Rossi <m.rossi (AT) iontrading (DOT) com>:

> you're right, at the moment the only open source implementation of olap4j that I know of is mondrian.
> But for example we have decided to use Olap4j as API for our internal proprietary system too.
> In the future there might be more "mondrians" out there.. unlikely but who knows.
>
> Michele
>
>
> On 19 April 2011 15:44, Andy Grohe <agrohe21 (AT) gmail (DOT) com> wrote:
> I think that states it clearly.
>
> Now we just need more olap4j implementations that Mondrian.
>
> So the xmla server requires an olap4j implementation in the engine side?
>
> Thanks
>
> Sent from my iPhone
>
> On Apr 19, 2011, at 8:00 AM, Michele Rossi <m.rossi (AT) iontrading (DOT) com> wrote:
>
>> hi,
>> The xmla servlet is not actually being split from the mondrian codebase (at least for now).
>> However its functionality is very distinct from Mondrian and refactoring the two functional areas is a matter of clean design and separation of concerns.
>>
>> Having an XMLA Servlet that can rely on a standard OLAP4J driver instead of the native mondrian API will allow other OLAP engines that have an OLAP4J driver to be exposed via XMLA.
>>
>> Another angle on this is that until now mondrian has been both a server (xmla) and an aggregation engine.
>> The idea is to split the two things.
>> Mondrian can keep being an engine, and the XMLA Servlet allows anyone with an OLAP driver to become an OLAP Server.
>>
>> Julian can probably put it in a better way.
>>
>> thanks,
>> Michele
>>
>>
>>
>>
>> On 19 April 2011 14:17, Andy Grohe <agrohe21 (AT) gmail (DOT) com> wrote:
>> What are the advantages of splitting out xmla from Mondrian to the community? At this time, they seem linked in my mind.
>>
>> Sent from my iPhone
>>
>> On Apr 18, 2011, at 11:20 PM, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:
>>
>>> Michele,
>>>
>>> I have checked in your changes as change 14208. I moved things around a bit -- I moved your olap4j connection factory out of XmlaServlet into a new derived class, Olap4jXmlaServlet. And the previous functionality, to start an embedded mondrian server, is in a new subclass MondrianXmlaServlet.
>>>
>>> I hope that I have preserved the intent of your changes.
>>>
>>> Thanks for the contribution. It definitely moves us down the road to an XMLA server that is independent of mondrian.
>>>
>>> Other users (including Pentaho BI server team), take note: Applications that used DefaultXmlaServlet should probably now use MondrianXmlaServlet.
>>>
>>> Julian
>>>
>>> From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
>>> Sent: Friday, April 15, 2011 1:36 AM
>>> To: Mondrian developer mailing list
>>> Cc: jhyde (AT) pentaho (DOT) com
>>> Subject: Re: [Mondrian] xmla over olap4j server
>>>
>>> [ re sending to the whole list as requested by Julian ]
>>>
>>> Hi Julian,
>>> I've completed the first stage of the xmla-over-olap4j work.
>>>
>>> I still haven't found out how to create patch files - it can probably be done using the p4 client, I will look at it tomorrow.
>>>
>>> For now I am attaching to this email the three files that I updated and an example web.xml that shows how the servlet could be deployed.
>>> You can find most of my changes easily by searching for [MROSSI].
>>>
>>> Initially I tried to split out the servlet from the rest of the Mondrian codebase but the dependencies are many and go fairly deep.
>>> I am not sure that such an endeavour would be very valuable.
>>> After all there is nothing wrong in just using the whole mondrian jar as it is.
>>>
>>> I've tested my code using Excel and the SimbaO2X adapter.
>>> I can successfully connect to a Foodmart olap database in the following way:
>>>
>>> Excel-->Simba-->My Server with the modified DefaultXmlaServlet-->Olap4j Xmla Driver-->A standard mondrian installation with a standard xmla servlet.
>>>
>>> I will need to make some more changes to handle the credentials passed by Excel in the XMLA requests.
>>> I did most of the work last year but never contributed it back.
>>>
>>> What do you think?
>>> How do you think I should proceed from this point?
>>>
>>> Many thanks!
>>> Michele
>>>
>>>
>>>
>>> On 11 March 2011 17:56, Julian Hyde <jhyde (AT) pentaho (DOT) com> wrote:
>>>
>>>
>>> From: Michele Rossi [mailto:michele.rossi (AT) gmail (DOT) com]
>>> Sent: Friday, March 11, 2011 1:43 AM
>>> To: mondrian (AT) pentaho (DOT) org; jhyde (AT) pentaho (DOT) com
>>> Subject: Re: [Mondrian] xmla over olap4j server
>>>
>>> [re-sending from my private email address as it's not working from my work address]
>>>
>>>
>>> Julian,
>>> I have a few questions for you:
>>>
>>> 1. How do I get started?
>>> Can you create an account on perforce for me with write permissions?
>>> Please submit your changes as patches attached to jira cases. We don't give people committer privileges until they have made a few successful contributions.
>>> 2. Olap4j drillthrough
>>> The mondrian olap4j driver implements drillthrough via the "executeQuery" method which returns a java.sql.ResultSet right?
>>> Can we not leverage that method to implement drillthrough on the xmla server?
>>> Possibly. Depends on your requirements. Mondrian's XMLA clients expect more in the XMLA response than is currently available in the ResultSet returned by that method. Therefore the XMLA server calls a method in XmlaExtra. The default implementation of XmlaExtra calls executeQuery. Same effect, longer route.
>>>
>>>
>>> 3. The new project:
>>> We will need a new "olap4j xmla server" project with its separate build an dependencies.
>>> Can you think of a good name for it?
>>> Perhaps Olap4jXmlaServer could be a good candidate
>>> Sounds reasonable.
>>> 4. How to build the new project:
>>> I know that mondrian is built using Ant.
>>>
>>> Have you ever thought about starting to use Maven?
>>> I've used Maven successfully for years and I've totally forgot how to use ant.
>>>
>>> I think it would also be beneficial in terms of linking olap4j releases with server releases.
>>> We could then distribute both olap4j, mondrian and the xmla server on public maven repositories.
>>> At this point I don't want to create a new project. I would like to work with the xmla server code in situ in the mondrian code base, to learn what the necessary changes are, and where would be the appropriate cut points. Then I will help you factor it into another project. But first, let's get it working in situ.
>>>
>>> Re. maven, see below.
>>>
>>> 5. Proposed solution
>>> I can put together a webapp project quickly using the following ingredients
>>>
>>> a. maven build
>>>
>>> b. unit tests based on mondrian:
>>> You create an in-process mondrian instance and connect to it using the mondrian olap4j driver.
>>> Then you hit the new server using the olap4j xmla driver.
>>> You can then compare results making assertions on the equality of metadata and values.
>>>
>>> c. The output artifact would a standard .WAR file
>>>
>>> d. Jetty launcher
>>> I propose the creation of a jetty launcher too.
>>> I can create such launcher using maven reasonably quickly.
>>> The result would be a tar.gz file with a number of sub-folders, one of them containing the .war file discussed above, others containing shared jetty libraries and finally the .bat and .sh launchers.
>>>
>>> We could then have a "cfg" folder with a template .properties file where a user would have to put the details of his/her favourite olap4j driver and the connection details.
>>> All of the above sounds fine. In due course. But please, don't make big changes as the first step. (I've found that the most successful committers are the ones who submit small patches at first.)
>>>
>>> In this case, the patches would be whatever hacks to mondrian's xmla server are necessary to build your flavor of the server. I will learn a lot from those patches.
>>>
>>> When time comes to create the new project, we can discuss using maven. You'd have to make a strong case, because it would be a Pentaho project (containing about 15k of mondrian source code, plus unit tests) and Pentaho projects have standardized on using an ant+ivy+subfloor infrastructure.
>>>
>>> Julian
>>>
>>>
>>> _______________________________________________
>>> Mondrian mailing list
>>> Mondrian (AT) pentaho (DOT) org
>>> http://lists.pentaho.org/mailman/listinfo/mondrian
>>
>> _______________________________________________
>> Mondrian mailing list
>> Mondrian (AT) pentaho (DOT) org
>> http://lists.pentaho.org/mailman/listinfo/mondrian
>>
>>
>>
>>
>> --
>>
>>
>> Michele Rossi
>>
>> <image001.jpg>
>>
>> Via San Martino, 52, 56125 Pisa, ITALY
>> T: +39 050 220 3894
>> m.rossi (AT) iontrading (DOT) com
>> http://www.iontrading.com
>>
>>
>> _______________________________________________
>> Mondrian mailing list
>> Mondrian (AT) pentaho (DOT) org
>> http://lists.pentaho.org/mailman/listinfo/mondrian
>
> _______________________________________________
> Mondrian mailing list
> Mondrian (AT) pentaho (DOT) org
> http://lists.pentaho.org/mailman/listinfo/mondrian
>
>
>
>
> --
>
>
> Michele Rossi
>
> <image001.jpg>
>
> Via San Martino, 52, 56125 Pisa, ITALY
> T: +39 050 220 3894
> m.rossi (AT) iontrading (DOT) com
> http://www.iontrading.com
>
>
> _______________________________________________
> Mondrian mailing list
> Mondrian (AT) pentaho (DOT) org
> http://lists.pentaho.org/mailman/listinfo/mondrian

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[Julian Hyde]

Michele Rossi wrote:

you're right, at the moment the only open source implementation of olap4j
that I know of is mondrian.

Well, there's the XMLA driver for olap4j. You can use that to talk to a lot
of databases, including the open source OLAP database, Palo.

And there is your use case: using the XMLA driver plus server to build a
proxy. Pretty useless on its own, but you could extend it to do some cool
architectural things: access control, routing, caching.

But for example we have decided to use Olap4j as API for our internal
proprietary system too.
In the future there might be more "mondrians" out there.. unlikely but who
knows.

Of course one hopes that there will be multiple implementations of a
specification. But a good spec it is useful in itself; it saves a lot of
design time if someone has already designed an API, test suite and tool set
for you. That's why I would advise others building OLAP capabilities to
implement the olap4j spec.

Other reasons to split out the XMLA server from mondrian:

1. Mondrian is a large piece of code. It is difficult to maintain and
especially difficult to contribute to. If we can carve it up into smaller
modules, we get more contributions.

2. The XMLA server was using mondrian's legacy API. We want to remove that
API someday.

3. The olap4j API is intentionally similar to XMLA. You'll find similarly
named classes and attributes in both. Making the XMLA server run on top of
the olap4j API.

4. Modularizing the XMLA server (i.e. removing unnecessary dependencies on
Mondrian) allows new architectural options. I had never dreamed that someone
would want to build an XMLA proxy.

5. Mondrian is an embeddable engine, but it doesn't quite have the services
necessary to make it a full server. (The ability to run as a service, e.g.
start up when the O/S starts; Authentication; Assignment of roles based on
who is making the connection; A repository of schemas.) Mondrian's XMLA
server had some of those services. Refactoring forced us to make those
services explicit, and pluggable.

Julian


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