Magma October 2006

magma@lists.squeakfoundation.org

10 participants
32 discussions

Re: Head on MagmaCollection
by Chris Muller 07 Nov '06

07 Nov '06

Not directly, because only #where: is something for MagmaCollection's which returns a Reader. Depending on your indexes, you can use & (and) to maximize query performance. But still nesting support is a very good idea so that MagmaCollections and Readers are 'symmetrical" w.r.t. where querying. To that end, it is something I have already been working on and am very close. Depending on whether you use "luxury" features like distinct: true or sorting on a non-optimized attribute, it must give you back a Reader on a *new* MagmaCollection. So if you then ask the reader for this new collection you can then do further where: query's on that. But I should probably take it one step further so you can use #where: on a reader, good idea.. ----- Original Message ---- From: Hilaire Fernandes <hilaire2006(a)laposte.net> To: magma(a)lists.squeakfoundation.org Sent: Friday, October 27, 2006 1:47:46 PM Subject: Re: Head on MagmaCollection Chris Muller a écrit : > If you have not explored MagmaCollections yet you should know they > provide Magma the much of the benefits of relational databases > without losing its ODBMS transparency at all. Central to this > philosophy is the fact that the where: syntax, for quickly creating > subsets of massive collections is, in most cases, identical to Is it correct to nest where: method? I guess it could be useful to speed up a query when your select criterias are deep in the tree. Hilaire _______________________________________________ Magma mailing list Magma(a)lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/magma

2 1

Re: Magma with 3.9 : Outage when creating repository
by Chris Muller 01 Nov '06

01 Nov '06

Hi Florent, I'm with you! In working on Magma's next release, I believe I have found the cause of this problem. As I've mentioned, I think the cause of the problem was that 3.9 opens files in "text" mode insteaad of binary mode by default. Opening a file in binary mode, closing it, then reopening it, puts it back to text mode! So I have fixed this. Please load the latest version of MagmaServerLoader from the Magma project on SqueakSource and I do not think you will encounter this problem again. - Chris ----- Original Message ---- From: florent trolat <trolat.florent(a)laposte.net> To: magma(a)lists.squeakfoundation.org Sent: Monday, October 23, 2006 4:29:38 AM Subject: Magma with 3.9 : Outage when creating repository Hello, I've an Outage when I try : MagmaRepositoryController create: 'c:\myMagmaFolder' root: Dictionary new ,I've seen this probleme has been already discuss in the mailing list but I've not understood the solution! I have to load another version of magma? (at this moment my version is the server version from squeaksource repository) Thank you. Florent. _______________________________________________ Magma mailing list Magma(a)lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/magma

2 2

Re: MagmaCollection and MagmaCollectionIndex
by Chris Muller 31 Oct '06

31 Oct '06

You couldn't inherit Object>>#hash, the identity hash, because it is not unique or consistent between images. If a class overrides with its own hash, I suppose you could use it but.. the hashes are used in where: query lookups and typically don't see querying on #hash: myCollection where: [ : each | each hash between: 123 and: 456 ] because it does not seem very meaningful; except in a MagmaSet or MagmaDictionary perhaps? ----- Original Message ---- From: Hilaire Fernandes <hilaire2006(a)laposte.net> To: magma(a)lists.squeakfoundation.org Sent: Monday, October 30, 2006 11:12:00 AM Subject: MagmaCollection and MagmaCollectionIndex Hello, Looking at the MagmaCollectionIndex, I am wondering what could prevent from using a general, default MagmaCollectionIndex implemented with the method: MaDefaultIndex>>indexHashForIndexObject: anObject ^ anObject hash I am sure there are plenty of reason to not do so, but I am note sure about. Hilaire _______________________________________________ Magma mailing list Magma(a)lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/magma

1 0

MagmaCollection and MagmaCollectionIndex
by Hilaire Fernandes 30 Oct '06

30 Oct '06

Hello, Looking at the MagmaCollectionIndex, I am wondering what could prevent from using a general, default MagmaCollectionIndex implemented with the method: MaDefaultIndex>>indexHashForIndexObject: anObject ^ anObject hash I am sure there are plenty of reason to not do so, but I am note sure about. Hilaire

1 0

MagmaCollection vs Smalltalk collection
by Hilaire Fernandes 30 Oct '06

30 Oct '06

In the situation of small read-only collection (<200) are there any good reason to not just use a standard Collection as OreredCollection and an appropriate ReadStrategy? I am in a situation where for some collection I need to search for collection elements from very long string attribute (>100 characters), a learning competency description. Hilaire

2 1

Re: Head on MagmaCollection
by Chris Muller 27 Oct '06

27 Oct '06

> I would like to use it seriously in a pet project. It is a kind of e-learning application composed of two blocks: a local morphic application with pedagogical activites and a distant data base repository. The two applications could be on different network location > on the Internet. Hi Hilaire, it sounds like a really cool project which would benefit greatly from MagmaCollections. The standard collections can of course be used in domain models but if they grow beyond a few hundred count then performance can suffer a lot. Further, concurrency issues can arise among these "popular" collections that multiple sessions want to add to frequently. (This could be improved for Sets and Dictionary's but, notwithstanding, MagmaCollections are still best for large). If you have not explored MagmaCollections yet you should know they provide Magma the much of the benefits of relational databases without losing its ODBMS transparency at all. Central to this philosophy is the fact that the where: syntax, for quickly creating subsets of massive collections is, in most cases, identical to standard select: block syntax (see the Swiki page for details about this). A lot of work has gone into making MagmaCollections work well and fast, and they do indeed. If you have any questions about them please, of course, feel free to ask here. - Chris

2 1

backing up
by Chris Muller 25 Oct '06

25 Oct '06

Although the fix for the "outage has occurred" error in 3.9 was in there, the other feature, the new file pooling, is still not ready. I shouldn't have posted it and I have withdrawn it from squeaksource until it can be finished. Until that time, if you are using 3.9, you may load the individual package: Magma server-cmm.183 for just the fix of the "outage has occurred" error. Sorry for the confusion, I'll try to get this fixed up real soon..

1 0

Head on MagmaCollection
by Hilaire Fernandes 24 Oct '06

24 Oct '06

Hi! It is fun to experiment with Magma and persistency. Thanks Chris for this great piece of software. I would like to use it seriously in a pet project. It is a kind of e-learning application composed of two blocks: a local morphic application with pedagogical activites and a distant data base repository. The two applications could be on different network location on the Internet. The data base repository contains knowledge representations and a very sharp log of the learner activity. So bascily after each learning act on the morphic application, a batch of log is saved on the distant database. The learner log is a tree populated with different Smalltlak objects (learningConcept, moprh, numbers, stream,...). So far I have implemented all the persistency with the use of standard Smalltalk collection. Now I am thinking about optimizing the data flow between the morphic application and the database. In particulary when a learner log need to be recorded in the data base. As implemented right now -- just standard collection and no readStrategy -- I guess that inserting a new log in the learner log tree imply first fetching a lot of the tree locally then adding the new entries. It is not wise and it is bit slow. Now I am wondering if the MagmaCollection is something that could help. Will it be possible to do a distant querry on the data base server to fetch the exact object from where I need to hook my new learner log? Of course I could used readStrategy to fully load locally major part of the learner log tree -- and probably I will do that -- but I am currious about the MagmaCollection options. Hilaire

1 0

Re: [Seaside / Magma] lost of session?
by florent trolat 23 Oct '06

23 Oct '06

Thank you very much for your help!!! I've tried to load Magma-Seaside, but the same probleme!! After that I've load Seaside-Examples-Store-Magma. I try to enter by seaside/config but I obtain : MagmaEnvironmentError: D:\esia\AOOA\SQ\Squeak3.9g-7055\magma image\magma\objects not found. I must create the magmaRepository ? How can I do this? thanks FLORENT. Keith Hodges a écrit : > florent trolat wrote: > > Dear Florent, > perhaps you need the package Magma-Seaside from repository http://www.squeaksource.com/MagmaTester > > You may also wish to load Seaside-Examples-Store-Magma in order to get the store example working to prove the system. > > best regards > > Keith > >> When I try to get an object from the magma database to my system I connot, after that, access to my seaside application. >> I obtain : >> "Request handling aborted; reload to retry" >> >> I 've inspect: I get a right object, but the seaside application seems to be lost. >> >> Someone can give me an idea to solve that? >> >> thank. >> >> PS: I've read that Seaside must use WAMagmaSession... I have not this class, it's a problem? >> _______________________________________________ >> Magma mailing list >> Magma(a)lists.squeakfoundation.org >> http://lists.squeakfoundation.org/mailman/listinfo/magma >> > > Send instant messages to your online friends http://uk.messenger.yahoo.com _______________________________________________ > Magma mailing list > Magma(a)lists.squeakfoundation.org > http://lists.squeakfoundation.org/mailman/listinfo/magma

1 0

[Seaside / Magma] lost of session?
by florent trolat 23 Oct '06

23 Oct '06

When I try to get an object from the magma database to my system I connot, after that, access to my seaside application. I obtain : "Request handling aborted; reload to retry" I 've inspect: I get a right object, but the seaside application seems to be lost. Someone can give me an idea to solve that? thank. PS: I've read that Seaside must use WAMagmaSession... I have not this class, it's a problem?

2 1

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

Magma October 2006