Hi all, As a follow-up to Djoerd's response and my questions about releases, let me say a little bit more about certain activities and sketch an analogy which we might mimick. We are trying to get many people enthusiastic about XML databases and XML-IR, as offered by MonetDB/XQuery in particular. To achieve some visibility for our work, I have for example started several activities in building production applications on top of MonetDB/XQuery and which use PF/Tijah. For example, I promised a demonstration in january to university-wide decision makers of the UT of a publication management application which uses XML-exports from our E-Prints system including the full-text of the papers. I hope it will be accepted as a production application used by all researchers of the UT next to E-Prints, which will over time demonstrate more advanced features and take over more and more functionality of E-Prints. As Djoerd pointed out, porting PF/Tijah to the algebra-backend in the proper way, is more a matter of a year than of a few months. However, it would be certain death to such production applications if the support for developing them would stop (since algebra-only means without PF/Tijah for a long time). Furthermore, many students following our courses and doing our projects are very interested in XML databases including XML-IR and probabilistic XML. A significant portion would be rather discouraged if they would not be able to grab a stable release to start working and get some bugs fixed. Microsoft once had the problem that they had ideas for a fundamentally different operating system kernel (NT). It was infeasible to make it fully backward-compatible with Windows 95 (on top of MSDOS), but it could also not abandon a large part of their userbase if their applications would not work anymore. Therefore, they had two release streams: one NT-based and one MSDOS-based. Both knew their releases until in the end. When most of the applications were ported or at least working on the new technology, they stopped releasing in the MSDOS-based stream. The algebra-backend is our `new technology', so can't we do something similar? Have an algebra-based release stream of MonetDB/XQuery (starting with 0.22) capable of running a significant portion of applications, and an mps-based release stream needed to serve the PF/Tijah- and ProbXML-applications. It would mean an extra package under "Download" on SF. Of course the algebra-based releases will have priority, but it would make it possible to have a new release for for example PF/Tijah when it is needed. Of course we will put in the required effort, but cannot do this alone. What do you think of this? Maurice. Djoerd Hiemstra wrote:
Dear all,
Very good: no more milprinting! In absence of Jan, please let me add the plans for PF/Tijah. To make things slightly more complicated: The PF/Tijah team would like to use the algebra release for porting our proprietary search extensions to XQuery Full-text, see: http://www.w3.org/TR/xquery-full-text/ Some initial design decisions that we like to follow have been made by Stefan Klinger at the University of Konstanz. The consequences of such a port would be:
1. XQuery syntax will be extended for text search queries (now only via user-defined functions) 2. All algebra operations must be score aware (i.e., if a score column exists, scores have to be propagated and aggregated)
We are aware that this affects everyone, although, only the extended queries will produce a score column, and algebra operations remain exactly the same if score columns are not there. The time goal of this release is XMAS 2008. In the mean time, we might not port the current PF/Tijah extensions to the algebra.
Best, Djoerd.
On Tue, 16 Oct 2007, Martin Kersten wrote:
LS,
Good to see this discussion. Although the topic is primarily MonetDB/XQuery it is good to keep an eye on the global picture. Releases include more stuff and requires a lot of time to prepare. (the release itself easily consumes several months of full time work, many delivered by free (weekend) time!!!!) Good planning and long-term internal use are a prerequisite. Something we still have to learn. Once the release cycle starts, the train can not stop and full power is/should be in the hands of a single person. The release manager currently is Sjoerd, one of the project admins!
As soon as a RC is available, those with a non-standard platform (windows, sun, mac, vista) should immediately double check to assure it basically works. This holds for all addressed and developers.
In this respect, the time frame mentioned below is overly optimistic. Anyone close to the core group should work on the HEAD to help uncover problems from day 1. Code changes should *not* be collected by individual programmers until release time . This is a major source of frustration, because you simply may not expect your team members to spent day and night to fight the 'last' bugs. Let alone to quick-test your latest feature or performance improvement. PLEASE, check-in daily your changes and make sure you have at least ran mtest on your platform. And most of all, know that your changes are scrutinized for potential quality problems by others. It is the best way to avoid many bugs.
Furthermore, changes in the interfaces visible to users and the effect on their databases should be kept to a minimum. Backward compatibility is a must as long as it is manageable. Beware that a change in storage structure may help a few extreme users, but may affects hundreds or thousands in their daily use. E.g. one of our users would have to unload/reload a 0.5Tb business critical application.
MonetDB/Query and MonetDB/SQL are intertwined. This creates responsibility both ways.
Peter Boncz wrote:
Stefan suggested rightly to move this discussion to the mailing list. I also changed the language into english for that purpose.
Maurice' original questions were:
(a) whether the new release would be algebra-only (short answer: hopefully).
In my opinion this can only be answered if the algebra version, in its full glory (without mps) is used for several months internally, e.g. using students for stress testing.
(b) whether our talk of a new release also refers to submodules, such as probxml and pftijah (short answer: yes)
Submodules basically follow their own release cycle. Regardless the source, e.g. datacells geom, .... Keeping in line is the responsibility of their owners, and the core developers should be aware that their changes may break the work of others. Or at least drain a possibly substantial amount of time.
(c) whether all issues on the wiki, see: http://www.pathfinder-xquery.org/wiki/index.php/Jupiter:_The_Algebra_Release needed for this action, have already been resolved (short answer: no)
The pathfinder wiki is a good example of team documentation.
I am looking forward to the upcoming release. The next one might be this year, but not necessarily includes everything on the drawing board.
regards, Martin
On Tue, Oct 16, 2007 at 05:23:43PM +0200, Peter Boncz wrote:
Hi Maurice, et al,
The release of (hopefully) this week will still be mps based. I also anticipate at least one bug-fix release (ie 0.20.2), or even more. However, the next major release (0.22) should be algebra based, in my opinion. I am certainly reluctant to keep investing any more effort in mps. I would aim for an mps-free release, yes.
The time-goal of that release is "XMAS 2007", as far as we are concerned. For the work of built-in functions I have good hope that with the help of Lefteris we can come a long way.
I hope and think updates can also be ported by joerd in that time-frame. As for pftijah, if Jan Flokstra has time, it should be possible to port that as well in 2-3 months.
There are some hairy issues, one of them being free-form recursion (needed by you), another one being precompiled modules (needed by XRPC). The resolution of these needs assistance from Munich, and maybe related. It needs a method to compile certain functions into scripted procedures (here MIL) and calling them. One algorithm is to do this for all functions in modules, as well as for all recursive functions. The issue to resolve is the representation of the parameters.
Depending on how much time Jan Rittinger has available for this, we will have to find creative solutions for this. Indeed, a backup solution would be to keep handling certain queries for the time being with mps, but that surely is ugly.
Peter
-----Original Message----- From: Keulen, M. van (Maurice) [mailto:m.vankeulen@utwente.nl] Sent: dinsdag 16 oktober 2007 16:38 To: Peter Boncz [CWI]; Stefan Manegold [CWI] Cc: Djoerd Hiemstra; Jan Flokstra; Henning Rode; Abdel Kader, R. (Riham) Subject: Nieuwe releases en mps-backend
Hoi,
Sorry dat ik niet bij de Skype-sessie van vandaag kon zijn, maar Riham vertelde me dat het onderwerp van nieuwe releases en de mps-backend ter sprake is geweest. Het riep wat specifieke vragen bij me op die ze niet allemaal kon beantwoorden:
a.. Is het de bedoeling dat een nieuwe release de mps-backend helemaal niet meer bevat of alleen maar de algebra-backend als default heeft? b.. Als jullie praten over "nieuwe release", bedoel je dan alleen een package van alle modules van MonetDB/XQuery? Maw zegt het niets over eventuele `subreleases' van individuele modules?
c.. Op de wiki hebben we een pagina met open issues voor de algebra-release. Wat is de status van die open issues? Ik zie namelijk op de pagina nergens dat bepaalde issues al opgelost/geïmplementeerd zijn. Ik Cc deze e-mail even aan de PF/Tijah-mensen, want hoewel er levendige discussies zijn hoe PF/Tijah naar de algebra-backend to porten, ik heb niet het idee dat er oplossingen zijn die op korte termijn realiseerbaar zijn. Evenzo het recursie-vraagstuk. Het lijkt me bijvoorbeeld voor de zichtbaarheid naar buiten toe onwenselijk als deze features ineens zouden wegvallen voor non-insiders. Of andere onwenselijke consequenties van het niet meer (sub)releasen van modules die gebaseerd zijn op de mps-backend.
Groetjes, Maurice.
-- ---------------------------------------------------------------------- Dr.Ir. M. van Keulen - Assistant Professor, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: m.vankeulen@utwente.nl, Phone: +31 534893688, Fax: +31 534892927 Room: ZI 3039, WWW: http://www.cs.utwente.nl/~keulen
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-- ---------------------------------------------------------------------- Dr.Ir. M. van Keulen - Assistant Professor, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: m.vankeulen@utwente.nl, Phone: +31 534893688, Fax: +31 534892927 Room: ZI 3039, WWW: http://www.cs.utwente.nl/~keulen