- Zope - Zope lists

RE: [Zope] Multiple Processes
by Martijn Pieters 29 Feb '00

29 Feb '00

From: David Binger [mailto:binger@centre.edu] > What prevents id collisions in Zope? > It looks like the the ObjectManager.py code > checks to see if the id is taken, and then > it reserves the id. > Is there a danger that 2 processes/threads > (z2.py -t 4?) could both check and reserve > the same id? > Is there something in Zope that prevents this > (improbable, but perhaps possible) problem? > > Is there certain way to find an > object id that is not taken? The ZODB takes care of concurrency and conflicts. I fyou want to know the technical details, see the UML model of the ZODB: http://www.zope.org/Documentation/Developer/Models/ZODB/ -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

1 0

Product Related Questions
by James W. Howe 29 Feb '00

29 Feb '00

Recently I created a new product in the Products folder. When I first created the product, I didn't have any python code so I didn't create a directory for the product in the Products directory. I simply used the "Add" button from the Products folder to create a new product. I then populated my Product with a couple of ZClasses. Yesterday I decided that I needed a new ZClass with a new Python base. I then created a directory under Products which had the same name as my Product. I added an __init__.py and a file containing my Python base class. In the __init__, I added my new Python class as a base class. I restarted Zope and expected to be able to add a new ZClass with a base class of my new base class. However, my base class didn't show up in the list. I looked at my Products directory and noticed that my python code had been compiled, so I knew that something happened. I tried a couple of different things and the base class never showed up. Finally, I moved my python code to a new directory and restarted. This time, a new product showed up in the Products list and my base class was now visible. My question is why? Why didn't things work when I created a directory in Products which matched a current Product name? On a related issue, I wanted to export my product so that I could import it into another Zope installation. However, my product doesnt have an "import/export" tab. Instead it has a "Distribution" tab. Using the Distribution tab, I can create a .tar file which includes an __init__.py, a product.dat and a version file. How do you use a distribution? Why can't I export my Product? If I add a new Product to the list, why doesn't Zope automatically create a subdirectory under Products to accommodate potential Python extensions? Thanks. James W. Howe mailto:jwh@allencreek.com Allen Creek Software, Inc. pgpkey: http://ic.net/~jwh/pgpkey.html Ann Arbor, MI 48103

1 0

RE: [Zope] Fourth request for help - Win2K+Zope
by Martijn Pieters 29 Feb '00

29 Feb '00

From: Jeff K. Hoffman [mailto:jeff.hoffman@goingv.com] > On Mon, 28 Feb 2000, Martijn Pieters wrote: > > > I am glad that this is solved. I ponder at the > case-sensitivity though. > > Maybe Python doesn't detect the OS properly? I am not fully > sure as to how > > Python decides when to ignore case, but it is clearly > broken on your Win2k > > install. Also, the lack of error messages was very vexing > and confusing. > > This is discussed partially in Guido's essay on the Python Package > mechanism. This is why you must specify the __all__ symbol in > a package's > __init__.py if you want it to behave well in a cross-platform > situation. > > At least, that's my take on it. ;-) Except that there are no 'import *'s from _packages_ in Zope, where __all__ would be needed. __all__ would only increase the maintenance overhead here. The PYTHONCASEOK might be a better idea, or better still, #undef-ing CHECK_IMPORT_CASE. We'll investigate first. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

2 1

a Zsql Method
by Alessandra Pessolano 29 Feb '00

29 Feb '00

Hello, I have the following DTML method: <dtml-var standard_html_header> <form action="ricercaxmodello" method="get"> <h2><dtml-var document_title></h2> Enter query parameters:<br><table> <tr><td ALIGN=LEFT>MODEL <select NAME="LISTA" multiple size="3"> <option VALUE="9000/779/C160L">C160L</option> <option VALUE="9000/770/J200">J200</option> <option VALUE="9000/770/J210">J210</option> </select></td></tr> <tr><td><input type="SUBMIT" name="SUBMIT" value="Submit Query"> </td></tr> </table> </form> <dtml-var standard_html_footer> I would make a Zsql Method, but I don't Know what is the right argument in the Zsql Method when there is a "select" and then I have some problems with the query template. Thanks in advance

1 0

RE: [Zope] Options for handling concurrency?
by Martijn Pieters 29 Feb '00

29 Feb '00

From: Michel Pelletier [mailto:michel@digicool.com] > Tony McDonald wrote: > > > > > > It's MySQL, but using the latest DA - I'm pretty sure I'm doing more > > than one query at a time as I set off a ZSQL query that takes 9 > > seconds from the MySQL command line, and then started to use aspects > > of the site that I *know* use MySQL lookups. BTW, the 9 second SQL > > query isn't used in the site! :) > > > > Oh one more thing, I'm pretty certain that the MySQL DA serializes ALL > requests because the MySQL library for python is not thread-safe. > Not Andy Dustmans MySQL DA. CodeCatalog.com is ver very fast, and it uses Andy's MySQL DA. Python wrote his own python libraries, specifically to make MySQL access thread safe. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

2 1

RE: [Zope] Options for handling concurrency?
by Martijn Pieters 29 Feb '00

29 Feb '00

From: Tony McDonald [mailto:tony.mcdonald@ncl.ac.uk] > At 9:43 am +0100 27/2/00, Martijn Pieters wrote: > > > >- Have a look at /Control_Panel/manage_debug. It'll show you > reference > >counts and currenlty open connections, which can be very helpful in > >targeting hotspots. > > Aye carumba! - what a lot of information. I'm going to start delving > around there and see what happens. Is there any additional > documentation available on what the info. means? - I've looked in the > ApplicationManager.py code is a wee bit over my head. It shows you reference counts, and how they change over time. Reference counts are how many references there are to classes and methods. This generally lets you see how many instances there are of those classes. It allows you to see where the hotspots might be. > > As an aside (to the list), looking around the ApplicationManager.py > reveals something called manage_profile. It looks like the main Zope > functions are being profiled here (ie not at the object level). It's > interesting, but it does seem to be a resource hog... But so is something in your app. You might want to run it and see what analysis you get. For more documentation of the data the profiler returns, see: http://www.python.org/doc/lib/profile.html > > >- Also, what DBMS are you using? If you are using a level 1 > or 2 DA (see > >http://www.zope.org/Members/petrilli/DARoadmap) then you can > do only one DB > >query at a time. It might be time to choose a different DB, > or if you are > >using the old MySQL DA, to upgrade. > > It's MySQL, but using the latest DA - I'm pretty sure I'm doing more > than one query at a time as I set off a ZSQL query that takes 9 > seconds from the MySQL command line, and then started to use aspects > of the site that I *know* use MySQL lookups. BTW, the 9 second SQL > query isn't used in the site! :) > This only shows that MySQL is multithreaded, not that the DA is. Run the expensive, 9 second query in a ZSQL Method. Then try and access another ZSQL Method on the same Zope server. If it is multithreaded, you should get results about as fast as when the heavy one isn't running. If it is the old MySQL DA, you'll have to wait until the 9 sec query is finished. > >- If you are using ZSQL a lot, do you use caching? Even a > cache expiry of 1 > >second would help a heavily hit site tremendously, noone > will notice the > >data returned being at most 1 second out of date.But all > hits with equal > >parameters on the same thread in Zope within that second > need only one DB > >query. > > I do use caching Martijn, but I must admit that it's been a hit and > miss affair. I'm trying to do as many of my SQL queries in external > methods (ironically for the performance), so I may well be losing a > lot of the caching performance breakthrough there .... hmmm. I wonder > if I could do something like... This shouldn't make any difference. Only in doing excessive loops in loops and the like, would an External Method be any use. -- Martijn Pieters, Software Engineer | Digital Creations http://www.digicool.com | Creators of Zope http://www.zope.org | mailto:mj@digicool.com ICQ: 4532236 | PGP: http://wwwkeys.nl.pgp.net:11371/pks/lookup?op=get&search=0xA8A32149 -------------------------------------------

2 1

Options for handling concurrency?
by tony 29 Feb '00

29 Feb '00

Hi all, One of my Zope sites is used by classes of students - up to 60 or so at a time. When they use the site the response time is really slow - they could be waiting minutes between clicks. The site uses ZSQL methods *extensively* and external methods. I realise that part of this problem is because of our Sun iron (2400 pystones - my *iMac* does 4400, and a PIII 500MHz does 5500), but as I can't get this site onto another box in the near future, I'm after other ideas. Can anyone give me some pointers (even just rule of thumb) to improve the response time? I was going to set the threads to be something like 32, but I've read other posts suggesting that wouldn't help too much. Is there someway I can profile what's going on for example? Any thought gratefully received. tone

5 9

(hopefully)last GUF question: authentication but no permission
by Lucas Vogel 29 Feb '00

29 Feb '00

I think I finally have it! My GUF prompts me with a login prompt that asks for a username and pasword(I would rather use the docLogin, but for some reason it doesn't. ?) I type in a valid username and password, it validates it with the database, and I get this in my console: 2000-02-29T13:41:35 INFO(0) GUF Successful authentication for user august (http://vogel.fdns.net:8080/aspire/models/acl_users) But I get a message box back from Netscape, saying 'Authorization failed. Retry?'. When I press cancel, it says: Zope Error Zope has encountered an error while publishing this resource. Unauthorized You are not authorized to access docLoginSuccess. My user is grouped as 'Authoriser', which is the same proxy name that has permissions to Login and logout, access contents information, and Use Database Methods for just about everything in the acl_users directory, which is also where my SQL Methods are. Authoriser has those permissions from the root down; why isn't it authenticating? Thanks -- Lucas Vogel lucas7(a)home.com ICQ: 44697169

1 0

programatically deleting ZClass instances?
by Darran Edmundson 29 Feb '00

29 Feb '00

Could someone send me a code snippet showing how to delete a ZClass instance? I've been trying to use manage_delObjects([ids, REQUEST]) - Delete a subordinate object. The objects specified in ids get deleted. without success. (If it matters, the ZClass instances I want to delete are children of a container ZClass.) I'd even settle for a DTML solution although I would like to see how to use the above method ... Cheers, Darran.

1 0

Re: [Zope] Using SQL aggregate functions
by Tres Seaver 29 Feb '00

29 Feb '00

John Williams wrote: > > >>>>> "Tres" == Tres Seaver <tseaver(a)palladion.com> writes: > > Tres> John Williams <J.A.R.Williams(a)aston.ac.uk> asked: > >> Date: 28 Feb 2000 08:17:42 +0000 > >> > >> I have been trying to use SQL aggregate functions in SQL > >> Methods to calculate some statistics e.g. something like > >> > >> SELECT id,count(id) from data group by field > >> > >> I am using MySQL, and the query works if entered directly from > >> another client, however Zopes SQL method returns an error. Is > >> this a known problem. Is there a known workaround or patch? > > Tres> I believe that the aggregate column has a "name" which the > Tres> DA doesn't like. Try aliasing it (the syntax for this > Tres> depends on your RDBMS):: > > Tres> SELECT id,count(id) as count_id from data group by field > > I was in fact using an alias, and this isn't cure the problem. I have > since looked in a bit more detail and the problem appears to occur > only when I use a join in the query, so it is a bit more subtle than I > originally thought. I saw another post with a patch for mySQL to cope with a column whose type was coming back "unhandled". Perhaps it would shed some light? Also, the SQL you posted looks a little odd: the non-aggregate column 'id' is not one of the 'group by' columns, which will cause Oracle at least to barf on the statement. -- ========================================================= Tres Seaver tseaver(a)palladion.com 713-523-6582 Palladion Software http://www.palladion.com

1 0