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From "David Nuescheler" <da...@day.com>
Subject Re: Jackrabbit = Kick Ass Tool (was: Jackrabbit = Big Trouble??)
Date Tue, 07 Aug 2007 16:03:00 GMT
Hi Mark,

I think this is an excellent idea, thanks a lot for putting in the effort.

I think the case that someone would like to store all their content
within the same RDBMS is common enough that we even should
have a blueprint example config in the documentation.

thanks again,
david


On 8/7/07, Mark Waschkowski <mwaschkowski@gmail.com> wrote:
> Hi David,
>
> I would like to update the wiki with the below information, as I think its
> quite valuable and would help new users without having to scour the mailing
> list. If you verify the following, I will update the wiki.
>
> -----For wiki:
> Using DBFileSystem as specified in the repository.xml:
> <Repository>
>         <FileSystem ...>
>
> and using the same database any of the PersistenceManager entries, the only
> things that need to be backed up are:
> 1) repository.xml
> 2) the database
>
> Then, to restore from a backup, all that would need to be done is to use the
> backed up repository.xml, restore the database using the backup, and the
> indexes will rebuild themselves when the system restarts. This will properly
> handle versioning as well.
>
> Note: rebuilding of indexes may take a significant amount of time
> ----end
>
> If all that looks correct, I'll fill in an example FileSystem and update the
> wiki. As well, any suggestions for the 'significant amount of time part'?
>
> Thanks,
>
> Mark
>
> On 7/30/07, David Nuescheler <david@day.com> wrote:
> >
> > Hi Bruce,
> >
> > thanks for your comment.
> >
> > > I am not fired by index problems. -)
> > > I just want to everybody realize it is very critical issue to back up
> > your repository.
> > > Currently, the solution is:
> > > 1) Backup DB data.
> > > 2) Backup your file system and you can delete all indexes of them.
> > > However, it is still a bug that JackRabbit v1.3 can not rebuild
> > everything from DB, in
> > > case your hard driver dies with all your repository file system.
> > Shouldn't that be solved by the DBFileSystem.
> > http://yukatan.fi/2007/1.4/org/apache/jackrabbit/core/fs/db/DbFileSystem.html
> >
> >
> > This allows you to store everything that is necessary for a complete
> > restore
> > in the DB, which means your DB backup is the only thing (beyond the
> > repository.xml) that you need to restore a complete JR instance.
> >
> > > My concerns are two:
> > > 1) Performance of navigation of Nodes which relates cache manager
> > resizing
> > I appreciate the performance issue. I am still not convinced that this
> > is related
> > with the cache manager resizing...
> >
> > > 2) Logic backup repository using JCR export/import API.
> > I agree that it would be desirable to have a built-in backup/restore
> > mechanism on a higher level.
> >
> > The JCR export/import is probably not the right layer,
> > since it only covers the content in a single workspace and has no
> > means to address things like nodetypes, versions or the
> > namespace registry.
> > And I think your most pressing issue should be addressed
> > by the DBFileSystem.
> >
> > regards,
> > david
> >
> > > -----Original Message-----
> > > From: bdelacretaz@gmail.com [mailto:bdelacretaz@gmail.com] On Behalf Of
> > Bertrand Delacretaz
> > > Sent: Friday, July 27, 2007 3:15 AM
> > > To: users@jackrabbit.apache.org
> > > Subject: Jackrabbit = Kick Ass Tool (was: Jackrabbit = Big Trouble??)
> > >
> > > Hi,
> > >
> > > I hate to play grumpy old man once again, but the recent trend towards
> > > Loud Subjects That Catch Peoples Attention does not really help the
> > > discussion, so let's rename this thread ;-)
> > >
> > > Bruce, if I read your message correctly, it looks like you have three
> > > problems with Jackrabbit:
> > >
> > > 1) Cache Manager resizes seem to slow your app down
> > > 2) You're going to be fired because you lost your index (or Jackrabbit
> > did)
> > > 3) You're not sure about which application pattern/content model to use
> > >
> > > So let's please tackle these one at a time, ideally in separate
> > > threads so that people can contribute efficiently to the discussion.
> > >
> > > Sorry if I'm being a bit harsh, but IMHO you started it with the
> > > choice of your message's subject ;-)
> > > -Bertrand
> > >
> > >
> > > On 7/27/07, Bruce Li < bli@tirawireless.com> wrote:
> > > > I have been in this Jackrabbit Community for a couple of months since
> > I joined repository project two months ago.
> > > >
> > > >
> > > >
> > > > First, I respect and appreciate all hard works contributed in current
> > JackRabbit project and definitely I am sure a lot of developers benefit from
> > this project. There are some people contribute their JackRabbit working
> > experience like David Nuescheler, who collects "7 DR Rules", which is
> > precious since current lack of document of JackRabbit, and they are "real"
> > working experiences.
> > > >
> > > >
> > > >
> > > > However, I also heard some negative voice from this community like
> > "JackRabbit is dead (for us)" from Frédéric Esnault. I suffer some troubles
> > from JackRabbit and it seems foundational problems. I would like to share
> > all my experience with you, and any feedback or good suggestion is
> > definitely what I want.
> > > >
> > > >
> > > >
> > > > Since these troubles are "big" troubles for enterprise use of
> > JackRabbit 1.3, let's discuss it from beginning.
> > > >
> > > >
> > > >
> > > > Question 1:
> > > >
> > > > Why do you select JackRabbit rather than Database as your repository
> > solution?
> > > >
> > > >
> > > >
> > > > There are a lot of answers for this question and it seems that
> > everybody who joins this community has already known the answers (It may be
> > formal document which was approved by your CTO).  However, my opinion, this
> > is the basic question really need to be discussed here.
> > > >
> > > >
> > > >
> > > > To answer this question, some technical key words to support
> > Jackrabbit may be "JCR API", "Lucene Search Engine" and so on. However, as
> > the user of JackRabbit, I would like to list the two key concerns why I
> > select JackRabbit as repository solution from Product Point of View:
> > > >
> > > >
> > > >
> > > > 1.      Quick and effective data search/fetch from volume content
> > repository
> > > > 2.      Build-in content version/revision control without extra code
> > > >
> > > >
> > > >
> > > > Now let me describe the big troubles I met in my use:
> > > >
> > > > 1.      Quick and effective data search or fetch from volume content
> > repository
> > > >
> > > >
> > > >
> > > > Experience: There are not many data on my repository which contains
> > hundreds of two major object nodes, each node (object) contains less than 20
> > properties (fields), including the other 5 child nodes (nested small
> > objects) and one of two major nodes(object) has one binary data (up to 1
> > megabyte). Unfortunately, the performance is not acceptable when I navigate
> > nodes of the major nodes. The main problem is the build-in Cache Manager of
> > JackRabbit resizes which costs uncertain time, which result the operation
> > very slow sometimes.  It is not easy to read those codes when debugging
> > Jackrabbit for performance tuning because there is no document about the
> > logic behind the index resizing.
> > > >
> > > >
> > > >
> > > > 2.      Content version/revision control
> > > >
> > > > Experience: This function works well on Jackrabbit v1.3. The main
> > problem is that all revision (except base revision) of node are lost when
> > export/import data from one repository to another repository. I am
> > discussing this issue because it concerns the repository backup.
> > > >
> > > >
> > > >
> > > > I just found in JackRabbit v1.3, there is no way to backup repository
> > using DB as persistence manager. I mean that there is no way to re-index
> > based on data on DB. The following is my case:
> > > >
> > > >
> > > >
> > > > In one repository server, the index (in file system) is corrupt which
> > causes all search failure. However, all data (in DB) is still alive, where
> > you can iterate all of them. After clean the whole repository file system
> > (most of them are index information), Jackrabbit can not correctly re-build
> > index based on the data on DB. If it happens on production repository, it
> > means: "My God, I am going to be fired". As I know, Jackrabbit v1.1 can
> > successfully re-index (creating totally new repository index (file system)
> > based on DB data).
> > > >
> > > >
> > > >
> > > > As the alternative solution to backup repository, I try to
> > export/import all nodes from repository to another repository using JCR
> > Export API (exportSystemView). The good news is that JackRabbot v1.3successfully
builds index (the whole file system) during the importing
> > process; the bad news is that it lost all revision of all versioning nodes.
> > Can you image how frustrate I am when I realize there is no way to backup
> > repository based on DB data?
> > > >
> > > >
> > > >
> > > > I just got the answer for the re-index issue for Jackrabbit v1.3: You
> > CAN NOT delete all file system. Only delete all indexes but keep the other
> > folders. Jackrabbit can re-index successfully when it starts up.
> > > >
> > > >
> > > >
> > > > Question 2:
> > > >
> > > > How can developer correctly use Jackrabbit (JCR) as their repository
> > solution?
> > > >
> > > >
> > > >
> > > > The expert of jackrabbit may see that I use object to describe node
> > and you may think it is not the pattern you are using Jackrabbit. So the
> > question is raised as "Which is the best practices (pattern) to use
> > Jackrabbit (JCR) as repository solution."
> > > >
> > > >
> > > >
> > > > From this community, I see a lot of developers use Jackrabbit by
> > fetching contents by path. It means that they do not need treat node as
> > object, instead, they put content on repository as asset, which can be
> > easily and effectively retrieved by a given path. This pattern exactly meets
> > the truth of "The simplicity is the best".
> > > >
> > > >
> > > >
> > > > My use of Jackrabbit is based on the business requirement, which need
> > to navigate most of nodes and reference nodes, check child nodes and
> > properties to find the proper content by a couple of business rules. I would
> > like to say that all performance issues are raised by nodes iteration
> > process. Even more, I have created generic classes using java reflect
> > package for bi-directory mapping between nodes and objects. For performance
> > improvement, the mapping supports generic child nodes lazy loading. However,
> > it seems all these jobs do not solve the performance problem although they
> > sound pretty "professional".  You may ask me: if you have such business
> > requirement, why not go to DB and build the full relationship for your
> > business model? J2EE developers all know how powerful java-db world is: the
> > mature ORM tool ( e.g. Hibernate), transaction management, batch data
> > fetching, performance tuning and so on. However, my question is: "Is there
> > any good pattern in current jackrabbit to effectively handle data fetching
> > with week relationship?"
> > > >
> > > >
> > > >
> > > > Now it is time to say some words to the jackrabbit developers and
> > contributors what I really want to say for the whole community:
> > > >
> > > >
> > > >
> > > > My begs:
> > > >
> > > > Guide, document and sample code is the king for any open source. How
> > frustrating for Jackrabbit developers find the incorrect pattern is applied
> > by users on their projects. On the other hand, how frustrating for
> > JackRabbit users can not find the good pattern to follow, which can save
> > their bunch of time. From product point of view, the search by XPath or
> > XQuery or SQL is not foundational issue. The foundational issue is one
> > effective search means covers most of important requirements from real world
> > and the document can be found in jackrabbit web site.
> > > >
> > > >
> > > >
> > > >
> > > >
> > > > I do believe Jackrabbit is qualified project and I really hope all
> > "best features" are documented, demoed and used by the whole community.
> > > >
> > > >
> > > >
> > > > Thanks
> > > >
> > > >
> > > >
> > > > Bruce
> > >
> >
>
>
>
> --
> Best,
>
> Mark Waschkowski
>

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