December 1999 - Zope

RE: [Zope] Cache question
by Michel Pelletier 09 Dec '99

09 Dec '99

> -----Original Message----- > From: Alexander Limi [mailto:alexander@mp3.no] > Sent: Thursday, December 09, 1999 10:15 AM > To: Michel Pelletier > Cc: zope(a)zope.org > Subject: RE: [Zope] Cache question > > From: zope-admin(a)zope.org [mailto:zope-admin@zope.org]On Behalf Of > > Michel Pelletier > > > In that case you would be able to hold your entire object > database in > > memory. If you have that kind of memory, go for it. > > Is there a quick and easy way to compute the size of your > objects? Am I > wrong to assume this is just the size of the ZODB/Data.fs? After a pack, yes. Unfortunately, there are not many database inspection tools. > Or > does Zope use > a lot more memory when there is activity in the DB? Oh you mean the runtime size of your objects? That's not really easily computable. An object may be small on disk, but dynamicly allocate megs of memory. -Michel

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RE: [Zope] Zope woes continue - server going down regularly. (pos sible solution)
by Michel Pelletier 09 Dec '99

09 Dec '99

> -----Original Message----- > From: Cayce Ullman [mailto:c_ullman@yahoo.com] > Sent: Wednesday, December 08, 1999 9:53 PM > To: Michel Pelletier; 'Tres Seaver'; zope(a)zope.org > Cc: Michel Pelletier; Cayce Ullman; panda(a)skinnyhippo.com > Subject: RE: [Zope] Zope woes continue - server going down regularly. > (pos sible solution) > > > > > Well, I'm not suprised to find out that it was > something I was doing wrong. However, the > symptons still sound fairly similar and I wouldn't > be suprised it someone his site is doing something > similar. Also, I tried : > x = Zope.app() > x.close() > > And it complains that x has no attribute close. > I talked more to Jim about this and we decided that it is a bad idea to open another connection in an external method. The reason is because when you're in an external method, you are allready bound to an object that has a connection, opening another and mixing changes between the wo connections is probably a bad idea. To get the *top level* root object in Zope, unwraped (no acquisition), do: self._p_jar.root()['Application'] The wraped object can come from PARENTS[-1] or you can walk up self._aq_parent. -Michel

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ZClasses, inheritance & other stuff.
by Alexander Limi 09 Dec '99

09 Dec '99

Zopistas, After fooling around a bit (a rather big bit, I might add (possibly even a byte)), I have come across something not mentioned in the docs. (Surprise!) My starting point is this: I want to create a superclass, which has the properties inherited by all the subclasses, like this: Software | |--Application | |--Game All software has properties that can (and should) be superclassed, like software_title, software_publisher etc. I tried to create ZClasses within ZClasses, but when I instantiate an object of the type Game, I can only edit the variables set specifically in Game, not the properties that should be inherited from Software. I want to superclass as many variables as possible, to avoid duplication of work. Most of the subclasses have 2 or 3 unique variables, all others are common. I am familiar with common OO parlance, but Zope is weird in some ways. I suppose the properties are inherited in the above example, but I want to be able to override the values from Software with instance variables/properties/whatever. And to edit them (the inherited properties) from the built-in zope manage form. How do I do this? Additionally, is there a way to automagically generate an addForm method AFTER editing the propertysheet for that class, to reflect the new variables (I'm getting tired of updating the HTML by hand every time :) Regards, Alexander.

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RE: [Zope] Cache question
by Michel Pelletier 09 Dec '99

09 Dec '99

> -----Original Message----- > From: Bruno Mattarollo [mailto:brunomadv@ciudad.com.ar] > Sent: Wednesday, December 08, 1999 11:29 AM > To: Michel Pelletier; zope(a)zope.org > Subject: Re: [Zope] Cache question > > > Hi Michel... > > Yes I saw that and read the ZCMG document... but what I > was asking, I > forgive me if I didn't express myself correctly in english > ;-) is: if I > raise the "target size", can I cause some problems to the > normal operation > of my Zope server? I mean, it's a production system and I > don't want to > bring it down... :-) If Zope tried to activate an object and doesn't have enough virtual memory you will get a memory error. If your cache is consuming all of your virtual memory like that though, you should seriously consider turning down your cache size or shortening the access time so that Zope is more agressive about keeping the cache size smaller. I disussed with Jim the possibility of Zope trying to recover from such a memory error by trying to flush the cache, but we decided that a memory error is kinda hard to allways get away from cleanly every time. In fact, I think that if your running out of memory, even just the process of trying to recover from that could cause more memory errors, which would sorta blow your exception logic out of the water. > I have aprox. 1200 objets, the target size is set to the > default (400) > ... I have 1019 objects in the cache... Should I raise the > target size to > 1200? In that case you would be able to hold your entire object database in memory. If you have that kind of memory, go for it. -Michel

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Re: Zope 2.1 does NOT work with NT Apache!
by Alexandre Ratti 09 Dec '99

09 Dec '99

At 10:31 08/12/1999 -0800, you wrote: >Date: Wed, 08 Dec 1999 17:42:57 +0100 >From: Rik Hoekstra <RikHoekstra(a)bigfoot.com> >Subject: [Zope] Zope 2.1 does NOT work with NT Apache! >To: zope(a)zope.org <snip> > > The documention is insufficient, because it is unix-specific; it talks > > about passing command line options to Zope, but Zope on NT can be ran as > > a Service, and how to pass command line options then? > > > >Um, you;ll have to hack the registry for that. Look in >HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ > <Service Name>\Parameters\start Well I'm not sure but there is also a Startup Parameters field in the NT Control Panel > Services dialog. Maybe you can use it to pass options. Alexandre

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RE: [Zope] Zope woes continue - server going down regularly. (pos sible solution)
by Michel Pelletier 09 Dec '99

09 Dec '99

> -----Original Message----- > From: Cayce Ullman [mailto:c_ullman@yahoo.com] > Sent: Wednesday, December 08, 1999 9:53 PM > To: Michel Pelletier; 'Tres Seaver'; zope(a)zope.org > Cc: Michel Pelletier; Cayce Ullman; panda(a)skinnyhippo.com > Subject: RE: [Zope] Zope woes continue - server going down regularly. > (pos sible solution) > > > Well, I'm not suprised to find out that it was > something I was doing wrong. However, the > symptons still sound fairly similar and I wouldn't > be suprised it someone his site is doing something > similar. Also, I tried : > x = Zope.app() > x.close() > > And it complains that x has no attribute close. Sorry, x is the application object. '_p_jar' is the database connection object. x._p_jar.close() BTW, all objects have an _p_jar that represents the connection to the database where they came from. In the multi-database future, this is good to know. -Michel

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Micro Soft SQL-Server
by Joachim Schmitz 09 Dec '99

09 Dec '99

How can one access an MS SQL running on NT server from Zope running on Unix ? Mit freundlichen Grüßen Joachim Schmitz WWW-Consultant email: js(a)ac-copy.net tel: +49-241-89491-0 fax: +49-241-89491-29

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RE: [Zope] Micro Soft SQL-Server
by Rob Page 09 Dec '99

09 Dec '99

> > If the SQL Server is v6.5 you can use the Sybase client libraries (and > > therefore the Sybase DA for Zope) on Unix. I don't believe tht anyone > > has figured out how to access an MSSQLv7 Server from Unix. > > > See http://odbc.linuxbox.com Yes, and Zope can be both an XML-RPC server and XML-RPC client so this would work. A possible downside -- depending on the application, is that you're almost sure to lose transaction integrity over any non-stateful connection (e.g., XML-RPC) to the database. --Rob

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Multi tier partitioning meaningful in some Zope apps ?
by Nitin Borwankar 09 Dec '99

09 Dec '99

All, After struggling for a while with all of the parts of the Zope framework in all it's complex and stark beauty a light seems to have gone off inside. Does the foll "application architecture" make sense Function Zope Tier (analogous) ======== =============== ============== =========== Visual -> DTML-Docs -> Light Middleware (JSP-like visual+some logic) Biz Logic -> DTML-methods -> Heavy Middleware (EJB-like non-visual all logic) Data Access -> ZSQL-methods -> Data API (JDBC-like) This stretches the truth somewhat especially in comparison to Java technologies. (EJB focuses on transactions a lot, with the intention of making them transparent). And of course Zope offers other component technologies that this does not encompass, but is this a viable way of a) Thinking about application architecture for the first set of apps while learning Zope ? b) Actually developing apps ? c) Partitioning tasks for distribution across skill sets ? I understand this will need addition usage conventions so as to "reduce the degrees of freedom" in Zope to a manageable subset for this "methodology" - such as :- "Use REQUEST['fieldname'] to extract data in the middle-tier and then call ZSQL, rather than using REQUEST['fieldname'] directly in the ZSQLMethod." The latter would make it a two-tier application which also may be useful structure for smaller apps where two of the tiers could be collapsed together. I would also welcome how/whether this "n-tier" partitioning would also be useful for thinking about the internals of Products and ZClasses when designing them. In the case of Products and ZClasses all layers may not be present. e.g. the ZODBC DA is primarily Data API layer only (management interface not withstanding). Comments/debate/flames invited Nitin Borwankar nitin(a)borwankar.com

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RE: [Zope] Micro Soft SQL-Server
by Roelof Naudé 09 Dec '99

09 Dec '99

> > How can one access an MS SQL running on NT server from Zope > running on > > Unix ? > > If the SQL Server is v6.5 you can use the Sybase client libraries (and > therefore the Sybase DA for Zope) on Unix. I don't believe tht anyone > has figured out how to access an MSSQLv7 Server from Unix. > See http://odbc.linuxbox.com Regards Roelof

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