On 3/3/08, devs-request@xwiki.org <devs-request@xwiki.org> wrote:

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Today's Topics:

  1. Re: Profiling: Why do attachments require so      much    memory
     (Sergiu Dumitriu)
  2. [VOTE] Change the attachment archive storage (Sergiu Dumitriu)
  3. Re: [VOTE] Change the attachment archive storage (Vincent Massol)
  4. Re: [VOTE] Change the attachment archive storage (Sergiu Dumitriu)
  5. [Proposal] XE 1.3 final release date (Vincent Massol)
  6. Re: Xwiki Enterprise 1.3 RC1 release date? (Vincent Massol)
  7. Re: About GSoC 2008 (Asiri Rathnayake)
  8. Re: Xwiki Enterprise 1.3 RC1 release date? (Sergiu Dumitriu)

----------------------------------------------------------------------

Message: 1
Date: Mon, 03 Mar 2008 17:28:21 +0100
From: Sergiu Dumitriu <sergiu@xwiki.com>
Subject: Re: [xwiki-devs] Profiling: Why do attachments require so
       much    memory
To: XWiki Developers <devs@xwiki.org>
Message-ID: <47CC2725.40707@xwiki.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Vincent Massol wrote:
> Nice work Sergiu. We should transform this into a jira issue to not
> forget it.
>

We should vote for it first.

> One other idea: store attachments on the file system and not in the DB.
>
> Thanks
> -Vincent
>
> On Feb 27, 2008, at 3:48 PM, Sergiu Dumitriu wrote:
>
>> Hi devs,
>>
>> Last night I checked what happens when uploading a file, and why does
>> that action require huge amounts of memory.
>>
>> So, whenever uploading a file, there are several places where the file
>> content is loaded into memory:
>> - as an XWikiAttachment as byte[] ~= filesize
>> - as an XWikiAttachmentArchive as Base64 encoded string ~=
>> 2*4*filesize
>> - as hibernate tokens that are sent to the database, clones of the
>> XWikiAttachment and XWikiAttachmentArchive data ~= 9*filesize
>> - as Cached attachments and attachment archive, clones of the same 2
>> objects ~= 9*filesize
>>
>> Total: ~27*filesize bytes in memory.
>>
>> So, out of a 10M file, we get at least 270M of needed memory.
>>
>> Worse, if this is not the first version of the attachment, then the
>> complete attachment history is loaded in memory, so add another
>> 24*versionsize*versions of memory needed during upload.
>>
>> After the upload is done, most of these are cleared, only the cached
>> objects will remain in memory.
>>
>> However, a problem still remains with the cache. It is a LRU cache
>> with
>> a fixed capacity, so even if the memory is full, the cached
>> attachments
>> will not be released.
>>
>> Things we can improve:
>> - Make the cache use References. This will allow cached attachments to
>> be removed from memory when there's a need for more memory
>> - Do a better attachment archive system. I'm not sure it is a good
>> idea
>> to have diff-based versioning of attachments. In theory, it saves
>> space
>> when versions are much alike, but it does not really work in practice
>> because it does a line-diff, and a base64 encoded string does not have
>> newlines. What's more, the space gain would be efficient when there
>> are
>> many versions, as one version alone takes 4 times more space than a
>> binary dump of the content.
>>
>> Suppose we switch to a "one version per table row" for attachment
>> history, with direct binary dump, then the memory needed for uploading
>> would be 6*filesize, which is much less.

--
Sergiu Dumitriu
http://purl.org/net/sergiu/

------------------------------

Message: 2
Date: Mon, 03 Mar 2008 17:34:07 +0100
From: Sergiu Dumitriu <sergiu@xwiki.com>
Subject: [xwiki-devs] [VOTE] Change the attachment archive storage
To: XWiki Developers <devs@xwiki.org>
Message-ID: <47CC287F.9090609@xwiki.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi devs,

As detailed in another mail
(http://lists.xwiki.org/pipermail/devs/2008-February/005344.html), the
current attachment archive mechanism is very inefficient. We should
write a new one, which stores attachment versions as plain binary data,
and see if the current core is pluggable enough to allow the old
mechanism to be preserved as a plugin, and possibly define other storage
mechanisms, like a filesystem based one.

Artem, do you think you can help, as this is something related to what
you've been working on?
--
Sergiu Dumitriu
http://purl.org/net/sergiu/

------------------------------

Message: 3
Date: Mon, 3 Mar 2008 17:40:39 +0100
From: Vincent Massol <vincent@massol.net>
Subject: Re: [xwiki-devs] [VOTE] Change the attachment archive storage
To: XWiki Developers <devs@xwiki.org>
Message-ID: <D5354D29-6FB9-41CB-A450-C77DE4E9BB54@massol.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

On Mar 3, 2008, at 5:34 PM, Sergiu Dumitriu wrote:

> Hi devs,
>
> As detailed in another mail
> (http://lists.xwiki.org/pipermail/devs/2008-February/005344.html), the
> current attachment archive mechanism is very inefficient. We should
> write a new one, which stores attachment versions as plain binary
> data,
> and see if the current core is pluggable enough to allow the old
> mechanism to be preserved as a plugin, and possibly define other
> storage
> mechanisms, like a filesystem based one.
>
> Artem, do you think you can help, as this is something related to what
> you've been working on?

My only worry is that last time we changed the database format we
spent several months stabilizing it... since there were lots of
problems. I'm not even sure we've finished stabilizing it fully...

So is there any chance that this would be simpler? :)

Thanks
-Vincent

------------------------------

Message: 4
Date: Mon, 03 Mar 2008 18:00:12 +0100
From: Sergiu Dumitriu <sergiu@xwiki.com>
Subject: Re: [xwiki-devs] [VOTE] Change the attachment archive storage
To: XWiki Developers <devs@xwiki.org>
Message-ID: <47CC2E9C.8070404@xwiki.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Vincent Massol wrote:
> On Mar 3, 2008, at 5:34 PM, Sergiu Dumitriu wrote:
>
>> Hi devs,
>>
>> As detailed in another mail
>> (http://lists.xwiki.org/pipermail/devs/2008-February/005344.html), the
>> current attachment archive mechanism is very inefficient. We should
>> write a new one, which stores attachment versions as plain binary
>> data,
>> and see if the current core is pluggable enough to allow the old
>> mechanism to be preserved as a plugin, and possibly define other
>> storage
>> mechanisms, like a filesystem based one.
>>
>> Artem, do you think you can help, as this is something related to what
>> you've been working on?
>
> My only worry is that last time we changed the database format we
> spent several months stabilizing it... since there were lots of
> problems. I'm not even sure we've finished stabilizing it fully...
>
> So is there any chance that this would be simpler? :)
>
> Thanks
> -Vincent
>

It should be simpler, as attachments are just binary blobs, while the
XML history is much too fragile.
--
Sergiu Dumitriu
http://purl.org/net/sergiu/

------------------------------

Message: 5
Date: Mon, 3 Mar 2008 18:18:18 +0100
From: Vincent Massol <vincent@massol.net>
Subject: [xwiki-devs] [Proposal] XE 1.3 final release date
To: XWiki Developers <devs@xwiki.org>
Message-ID: <FE2B2F15-5128-47CC-90B7-CAF96398BADE@massol.net>
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

Hi,

I'm proposing to revise the 1.3 Final release date to this Friday 7th
of March 2007.

We've already fixed the major issues raised in 1.3RC1 but I think we
need a few days to let people report any issues they might have had
with 1.3RC1.

Let me know what you think and especially if you don't agree. I'm
proposing to do the release.

Thanks
-Vincent

------------------------------

Message: 6
Date: Mon, 3 Mar 2008 18:23:39 +0100
From: Vincent Massol <vincent@massol.net>
Subject: Re: [xwiki-devs] Xwiki Enterprise 1.3 RC1 release date?
To: XWiki Developers <devs@xwiki.org>
Message-ID: <161441E7-DC86-48ED-A91A-A8F143A2FC4B@massol.net>
Content-Type: text/plain; charset="us-ascii"

On Feb 27, 2008, at 3:17 PM, Everitt, Glenn wrote:

> Is the plan to provide a  xwiki-enterprise-web1-1.3-rc1.war file on
> the Xwiki Download page?  When do you think this would be
> available?  Would it be better to pull it directly from svn?  If I
> get it from svn how is the RC1 release marked?
>
It's been released a few days ago...
> I noticed that you were looking at using GWT Html editor.  Doesn't
> GWT Html editor just wrap the FCKEditor?  What is the advantage of
> using GWT Html Editor instead of just using the FCKEditor?
>
I have no idea. Anyone knows?

Thanks
-Vincent

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Message: 7
Date: Mon, 3 Mar 2008 22:57:55 +0530
From: "Asiri Rathnayake" <asiri.rathnayake@gmail.com>
Subject: Re: [xwiki-devs] About GSoC 2008
To: "XWiki Developers" <devs@xwiki.org>
Message-ID:
       <9fd36c290803030927g202b5c93l4e104d1744f4e8ef@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"

Hi Vincent,

On Mon, Mar 3, 2008 at 6:23 PM, Vincent Massol <vincent@massol.net> wrote:

>
> On Mar 2, 2008, at 7:03 AM, Asiri Rathnayake wrote:
>
> Hi,
>
> On Sat, Mar 1, 2008 at 7:54 PM, Vincent Massol <vincent@massol.net> wrote:
>
> >
> > On Mar 1, 2008, at 3:12 PM, Asiri Rathnayake wrote:
> >
> > Hi All,
> >
> > Sorry if this is the wrong place / time to ask this question.
> >
> > I wanted to know whether XWiki will participate in GSoC 2008<http://code.google.com/soc/2008/>.
> > ( care to hint some project ideas ? )
> >
> >
> > answer is yes!
> >
> > We all need to think about cool project ideas we want to achieve. We
> > could start by reviewing the leftovers from last year + add some new ones.
> >
>
> Do we have syntax highlighting in XEclipse ? I think this is one of the
> leftovers. But I'm not sure whether itself alone be enough for a summer
> project.
>
>
> No we don't have it AFAIK. However I don't think it's complex to do since
> there's a velocity editor plugin. It should simply be a matter of using it.
> As you say this sounds like something a bit too small. However if you have
> other large ideas that you could add with this, then it's worth proposing
> them on http://dev.xwiki.org/xwiki/bin/view/GoogleSummerOfCode/
>

Once i thought it would be nice to have off-line rendering of pages (no need
to be connected to view the results) in XEclipse (is this possible ?). But
now I'm wondering if it's worth putting another GSoC project on XEclipse
(?), since fabio seems to be doing a great great great job on XEclipse ....

I personally would like to get familiar in core xwiki development (in
contrast to add-on development), but i got no idea that would suite a summer
project yet :(

Hope you (core developers) will put up something cool (and challenging) soon
:)

Thanks a lot.

- Asiri

>
> Thanks
> -Vincent
>
> Thanks.
>
> - Asiri
>
>
> > If anyone has cool ideas please send them on this list. I'll organize a
> > new space for collating them on xwiki.org in a few days.
> >
> > Thanks
> > -Vincent
> >
>
> _______________________________________________
> devs mailing list
> devs@xwiki.org
> http://lists.xwiki.org/mailman/listinfo/devs
>
>
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Message: 8
Date: Mon, 03 Mar 2008 18:37:24 +0100
From: Sergiu Dumitriu <sergiu@xwiki.com>
Subject: Re: [xwiki-devs] Xwiki Enterprise 1.3 RC1 release date?
To: XWiki Developers <devs@xwiki.org>
Message-ID: <47CC3754.3090906@xwiki.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Vincent Massol wrote:
>
> On Feb 27, 2008, at 3:17 PM, Everitt, Glenn wrote:
>
>> Is the plan to provide a  xwiki-enterprise-web1-1.3-rc1.war file on
>> the Xwiki Download page?  When do you think this would be available?
>> Would it be better to pull it directly from svn?  If I get it from svn
>> how is the RC1 release marked?
>>
> It's been released a few days ago...
>>
>> I noticed that you were looking at using GWT Html editor.  Doesn't GWT
>> Html editor just wrap the FCKEditor?  What is the advantage of using
>> GWT Html Editor instead of just using the FCKEditor?
>>
> I have no idea. Anyone knows?

We're not planning on using an existing GWT editor, but to write our
own, so that it is tightly integrated with XWiki. And since it will be
written in java, we won't have the current problem with different
look/behavior between view, edit in wiki and edit in wysiwyg.

And FCK is not suited for XWiki, as it is a HTML editor, and we need a
wiki editor.
--
Sergiu Dumitriu
http://purl.org/net/sergiu/

------------------------------

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