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RE: [Zope] zope vs. memory [was Re: Refcounts, ZODB Cache and memory leaks?]
by Dieter Maurer 30 May '05

30 May '05

Please stay on the list! Readded... Dylan Jay wrote at 2005-5-29 23:31 +1000: >> >- Memory grows and mostly doesn't shrink. >> >> That's normal behavior. > >Normal as in desirable or normal as in known bug? Normal as in "extremely difficult to avoid". When you read a book about memory management and look at the operating system provided API for memory management you will understand why. >> >- Its not due to objects that can't be collected by the GC >> >- Its not due to the ZODB cache >> > >> >That leaves the following causes I think >> >- RAMCache etc and module/class variables. Either mine, plone's or >> zope's. If the reference counts as shown by "Control_Panel --> Debug information" do not show them, then the leaked objects are neither class nor "ExtensionClass" instances and are probably elementary Python types. Some moths ago, I found such a leak in the "TempStorage" implementation. However, this is fixed in recent Zope versions (I think since 2.7.5). > ... >> Python has no big chance. The memory management options of the >> underlaying operating systems are quite limited and Python >> uses the C memory management at its lowest level. >> Thus, it must live with what "C" provides. > >I don't really understand the implications of what your saying. Are you >saying that oses don't allow python to free memory? Something like that: "posix" provides two ways to add address space for a process: "brk" and "mmap". "brk" allows to add and release space at the *end* of the address space. You cannot release such space unless a complete range is free at the very end! "mmap" can add (and release) space anywhere but only in large chunks and only at corresponding boundaries. You can use "mmap" only for large memory blocks managed atomically (i.e. allocated and released as a whole). The "C" "malloc" usually uses "brk" to allocate large chunks of memory and subdivides them as needed (for efficiency reasons). While it would be possible to check for the possibility to release such blocks again, it would be expensive (and not so often successful). Therefore, it is rarely done. Read more in a book about memory management! > ... >am I right in saying that using >the catalog involves lots of btree objects which are objects and would not >be affected by the memory issue above? "BTree" objects are objects and would be counted in the "Reference Counts" display of "Control_Panel --> Debug Information". You should be able to detect leaks involving them by analysing this display (do not forget to flush the caches before you trust the reference counts!). > ... >> Did I not tell you about a special Python build to >> analyse memory leaks? > >No. You can build Python to account for any allocated object. However, all extensions must then be build with this same option (otherwise, the object structures do not agree and chaos results). You will need many hours to analyse the thousands of objects to distinguish between the leaked objects and the one rightfully used by the application... -- Dieter

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Re: [Zope] DTML in Zope 2 vs Zope 3
by Jaroslav Lukesh 30 May '05

30 May '05

Dne čtvrtek, 26. května 2005 22:03 Greg Fischer <retheoff(a)gmail.com> napsal(a): > I am just curious, why is DTML not good? It does 9 out of 10 things I > want quite easily. From my perspective, I really dont want to learn > new ways of doing things if this works. I also have no desire to do > templating. I can see the need for it in a large development shop,but > for me, a 1 guy operation, I have no desire to complicate things. > DTML works so easy for me. > > I do use Python scripts here and there for small and odd things that > would be difficult or impossible to do in DTML, but like I said, > that's maybe only 10% max of the functionality that I need to provide. > (probably 5-6%) Having to move everything in Python is a hassle that I > dont plan on doing for a few years. I'll just keep using Zope 2. > > I'd also be curious to know from all you other developers, what > percentage of tasks that you need to perform or functionality you need > to provide can be provided simply with DTML? Like for me, I can do > quickly and easily do 90% of what I need in DTML. > > Is DTML really that much harder to use? > > I understand the whole idea of separating the logic and the > presentation, and I guess, is that part of the reason why DTML is not > as good? But, for me, that separation is more complicated. DTML is > easier for me. (partly because I know it) > > I dont know, DTML and the "everythings an object" concept in Zope are > the very things that make Zope so attractive for a small time operator > like me. I hate to see them deprecated just because it doesnt work > for the larger companies out there. Of course, I may be totally > ignorant about all this, huh? I absolutelly agree with you, it is like my words. But separation of logic and presentation could be done successfully in DTML too. ZPT, which have "separation argument" is not as easy to make totally separated design as marketing says, for example see Plone - try to customize plone site to absolutelly different custom design - it is near impossible. -- Jaroslav Lukesh ----------------------------------------------------------- This e-mail can not contain any viruses because I use Linux

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How to modify 'title' of an object
by Rares Vernica 29 May '05

29 May '05

Hi, How can I modify the 'title' of an object in DTML? Thanks in advance, Rares _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com

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Receiving mails
by Varun Parange 28 May '05

28 May '05

hi, i have downloaded an SMTP server and using it i can send mails with the help of Zope MailHost.... however i would also like to recieve mails.... how do i do this..... which additional products do i need to download... regards, varun __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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strftime and timezone
by Hong Yaun 28 May '05

28 May '05

My zope application accesses a Postgres table with a timestamp field 'create_date' through ZPsycopgDA and I want to use strftime to format the date the way I like. However, I find that strftime returns a value that is not the same time as the original one, very likely due to some behind-scene timezone adjustment, which I don't understand and don't know how to control. The following PythonScript code is an illustration of my problem: msg=context.get_some_message t=msgs.create_date print t print t.strftime('%Y-%m-%d %H:%M:%S') return printed When called, the script returns: 2005/03/09 03:36:45 US/Central 2005-03-09 17:36:45 The question is, where does the 'create_date' object get the timezone information for the formatting, and how to achieve my desired output, that is '2005-03-09 03:36:45'? By the way, 'create_date' doesn't seem to be a Zope DateTime object, for when I tested with: t=DateTime() print t print t.strftime('%Y-%m-%d %H:%M:%S') The two prints give the same time value. For your information, in my ZPsycopgDA property, I have choosen the option: 'Use Zope's internal DateTime module (instead of mxDateTime)'. My zope version: 2.7.4 under Linux. Thanks for your help. Hong Yuan

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LDAPUserFolder at Zope root
by Oscar Figueiredo 28 May '05

28 May '05

Hello, this might be trivial but I just can't find a way to do it. How does one replace the initial UserFolder at Zope root with a LDAPUSerFolder ? I tried the dummy way : delete the acl_users with an intent to instanciate a LDAPUSerFolder afterwards but that locked me out in a way I could do nothing but recreate a new Zope instance... skip-authentication-checking in etc/zope.conf didn't help... Zope 2.7 debian testing package. Oscar

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Re: [Zope] Create a list using DTML.
by Fernando Lujan 28 May '05

28 May '05

On 24/05/05, J Cameron Cooper <zope-l(a)jcameroncooper.com> wrote: > Personally, I'd probably just do something like:: > "{1,2,3}"[1:-1].split(',') This code works as expected... Thanks! :) -- Fernando Lujan

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Opening .doc files in zope
by Allen Huang 27 May '05

27 May '05

Is there any way to open a .doc files using dtml or script and print them?? --------------------------------- Yahoo! Mail Stay connected, organized, and protected. Take the tour

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Uploading rst docs & Put_factory
by Andrew Malcolmson 27 May '05

27 May '05

I want to upload a restructured text (rst) document to my Zope server via FTP and have its content type recognized. I understand that I need to make an entry in PUT_factory.py but I need some guidance here. The following attempt didn't have any effect (that is, the type of the uploaded file is still just 'text/plain'): elif typ.endswith('rst'): ob= ReStructuredTextDocument(name)

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Zope MailHost Query
by Varun Parange 27 May '05

27 May '05

hi, how do i receive mails using Zope mailhost?? --------------------------------- Do You Yahoo!? Yahoo! Small Business - Try our new Resources site!

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