[Zope-dev] FW: Zope & optimistic transactions.

[Clark OBrien]

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[Clark OBrien]  I  think I was sending to zope-dev@zope.COM my mistake- but
an easy one to make. 
> From: 	Clark OBrien  
> Sent:	Monday, November 05, 2001 7:14 AM
> To:	'chrism@zope.com'; 'k_vertigo@yahoo.com'
> Cc:	'zope@zope.org'
> Subject:	Zope & optimistic transactions.
> 
> 
> Chris,
> I set up a test harness to exercise zopes optimistic transaction
> management.
> My test immediatly caused a ZODB exception.
> 
> I am running zope 2.42. on win 2k, the scripts are attached.
> Results below:
> 
> As you recall I posed the following question:
> 
> What if you had a directory structure like:
> Folder1
>     Folder-2
>        Folder-3
>           ...
>             ..
>                 Folder-n
> Each folder had an attribute foo and there were two scripts, script1 and
> script2. 
> script1 modified foo on one Folder only while script2 traversed all the
> folders modifying the attribute foo on each one of them.
> Would the script2 ever commit while the fist while script1 was
> continuously called. This is interesting because a call to  script2 would
> never finish before several calls to  script1 finished.
> 
> I set up a simple test with only 10 folders. I then wrote the script below
> changeLevel2 that is my scri1 above and changeFolders that is my script2
> above.
> I ran changeLevel2 in a loop using the following code:
> ----------------------------------------script----------------------------
> -------------------
> import urllib
> params = urllib.urlencode({'theText': 'Vitamin D'})
> while 1:
>  f = urllib.urlopen("http://localhost:8080/Test/changeLevel2?%s" % params)
>  print f.read()
> -----------------------------------------script---------------------------
> ---------------------
> 
> 
> I then ran the script changeFolders from my browsers.
> The result was the following error message:
> 
> ------------------------------------------------------------
> ZODB.POSException.ConflictError
> 
> Sorry, a site error occurred.
> 
> Traceback (innermost last):
>   File C:\zope\lib\python\ZPublisher\Publish.py, line 223, in
> publish_module
>   File C:\zope\lib\python\ZPublisher\Publish.py, line 200, in publish
>   File C:\zope\lib\python\ZPublisher\Publish.py, line 200, in publish
>   File C:\zope\lib\python\ZPublisher\Publish.py, line 200, in publish
>   File C:\zope\lib\python\ZPublisher\Publish.py, line 195, in publish
> ----------------------------------------------------------
> 
> 
> 
>  <<scripts.txt>> 

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Content-Type: text/plain;
	name="scripts.txt"
Content-Disposition: attachment;
	filename="scripts.txt"

-----------------------------changeFolder ------------------------------------------------------
#changeFolder
#params list:  theFolder,theText

theFolder.manage_changeProperties({'foo':theText})

----------------------------------end changeFolder-----------------------------------------------




-----------------------------------changeFolders--------------------------------------------------
#changeFolders
#Paramater list: myString
# this method changes the attribute foo on several folders.


newFolder = context.getChild("TestFolder" )
newFolder.manage_changeProperties({'foo':myString})
import string 

for i in range(1,10):
 newFolder = newFolder.getChild("TestFolder" )
 for i in range(1,10):
  # lets do something expansive
  #for j in range(1,100):
   #string.find("its a great day to code python","day")
  newFolder.manage_changeProperties({'foo':myString})


return "all properties changed"
----------------------------------------------end changeFolders----------------------------------------

---------------------------------------------changeLevel2------------------------------------------------
#changeLevel2
#paramater list: theText
theFolder = context.getChild("TestFolder" )
context.changeFolder(theFolder,theText)
return 'ok'
---------------------------------------------end changeLevel2--------------------------------------------




---------------------------------------------createFolders-----------------------------------------------
temp = context.manage_addFolder('TestFolder','TestFolder')
newFolder = context.getChild("TestFolder" )
newFolder.manage_addProperty("foo","this is a test string", "string")

for i in range(1,10):
 newFolder.manage_addFolder("TestFolder","TestFolder")
 newFolder = newFolder.getChild("TestFolder" )
 newFolder.manage_addProperty("foo","this is a test string", "string")
--------------------------------------------end createFolders -----------------------------------------------

---------------------------------getChild-------------------------------------------------------------------
#getChild
#param list: child

"""
getChild: Utility function

Returns ObjectManagerItem whose ID matches child parameter.
Context must be ObjectManager.
"""
for (oid, obj) in context.objectItems():
    if oid == child:
        return obj
else:
    return None
----------------------------------------end getChild -----------------------------------------------------

----------------------------------------makeNewFolder-----------------------------------------------------
#makeNewFolder
#param list: root

root.manage_addFolder('TestFolder','TestFolder')
root.manage_addProperty('foo','The world is round only to those who know it',"string")
return root.getChild('TestFolder')

--------------------------------------end makeNewFolder-----------------------------------------------











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