Re: [Zope-dev] Preliminary findings: Zope 2.7 leakage caused by errors
Andreas Jung wrote at 2004-5-20 10:02 +0200: >I have not followed the discussion but is this leak as serious as it should >be resolved >before the next 2.7.1 beta1 release? I doubt that it is a Zope bug... I am unable to reproduce any leak in connection with error handling. Otherwise, we can only answer your question when we know the reason for the leakage. -- Dieter ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
Re: [Zope-dev] Preliminary findings: Zope 2.7 leakage caused by errors
I have not followed the discussion but is this leak as serious as it should
be resolved
before the next 2.7.1 beta1 release?
Andreas
--On Donnerstag, 20. Mai 2004 9:52 Uhr +0200 Dieter Maurer
<[EMAIL PROTECTED]> wrote:
[EMAIL PROTECTED] wrote at 2004-5-19 14:44 -0400:
...
Right now I've focused on finding out why the Requests are still around.
Using the gc module, I've found that all leaked requests are being held
by a dictionary. If I look at said dictionaries, this is what they
might look like:
{'REQUEST': },
{'REQUEST': },
These dictionaries look like the "instance dict"s of
the "ZPublisher.BaseRequest.RequestContainer"s.
When you have any cycle involving an AcquisitionWrapper,
then its reference to the "RequestContainer" will keep this alive
together with its instance dict.
You may analyse the content of your requests.
Do they contain acquisition wrapped objects (or other objects
with (maybe indirect) references to this dict)?
If not, "REQUEST" does not seem to be the root of your cycles
but rather a side effect.
More important notes:
* When you see "AcquisitionWrapper"s in the reference information
in "Control_Panel --> Debug Information", then
there *must* also be other prominent ExtensionClass'es --
the "aq_base" of these wrappers.
These classes may provide a valuable clue towards the cause
of the cycles -- of global variables (by the way).
* The reference information in "Control_Panel" covers only
instance objects but not elementary Python data types.
Thus, when cycles are caused by elementary Python objects,
we may not directly see them in the list.
GC's "DEBUG_LEAK" may provide some information.
* The leaks may not be caused by cycles at all (though it is
the most likely cause) but could result from a global
cache containing references to acquisition wrapped objects.
Such a cache should never exist -- global variables and
class attributes must never directly or indirectly reference
persistent objects -- as this results in nasty persistency bugs.
Nevertheless, sometimes software is buggy. I noticed
such a cache in Archetypes 1.3a2 (fixed in newer versions).
Said dictionary does not seem to be referred to by anything, at least not
anything the gc module can find (gc.get_referrers()).
That's probably because "RequestContainer" is an ExtensionClass
and ExtensionClasses are not yet (only from Zope 2.8 on) GC aware.
...
Also I
understand zope.org suffers from this? :)
Leaks can have innumerable causes. It is by no means clear
that your leak and the one on Zope.org has the same cause.
Based on this information also, I have no reason to believe this is
caused by product code ... I have to guess it's a Zope bug?
I do not observe leaks in my Zope installation -- even when
I make an error stress test.
This does not mean it could not be a Zope bug --
but it implies that such a bug does not surface regularly, at most
under special conditions.
In some ways this is motivating me to reduce the number of errors that
could occur, but because ALL errors seems to cause the problem, I
ultimately have no control over it and under certain circumstances I
suffer heavily from this. 404's alone probably cause this (I'm plannign
to test that explicitely as well).
It does not here
Something is special with your installation -- maybe "Localizer" as
Tres suggested, maybe another misbehaving product.
___
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Re: [Zope-dev] Preliminary findings: Zope 2.7 leakage caused by errors
[EMAIL PROTECTED] wrote at 2004-5-19 14:44 -0400:
> ...
>Right now I've focused on finding out why the Requests are still around.
>
>Using the gc module, I've found that all leaked requests are being held by a
>dictionary. If I look at said dictionaries, this is what they might look
>like:
>
>{'REQUEST': URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
>_site/francais/mapsatoz>},
> {'REQUEST': URL=/VirtualHostBase/http/atlastest2.ccrs.nrcan.gc.ca:80/VirtualHostRoot/_vh
>_site/francais/mapsatoz>},
These dictionaries look like the "instance dict"s of
the "ZPublisher.BaseRequest.RequestContainer"s.
When you have any cycle involving an AcquisitionWrapper,
then its reference to the "RequestContainer" will keep this alive
together with its instance dict.
You may analyse the content of your requests.
Do they contain acquisition wrapped objects (or other objects
with (maybe indirect) references to this dict)?
If not, "REQUEST" does not seem to be the root of your cycles
but rather a side effect.
More important notes:
* When you see "AcquisitionWrapper"s in the reference information
in "Control_Panel --> Debug Information", then
there *must* also be other prominent ExtensionClass'es --
the "aq_base" of these wrappers.
These classes may provide a valuable clue towards the cause
of the cycles -- of global variables (by the way).
* The reference information in "Control_Panel" covers only
instance objects but not elementary Python data types.
Thus, when cycles are caused by elementary Python objects,
we may not directly see them in the list.
GC's "DEBUG_LEAK" may provide some information.
* The leaks may not be caused by cycles at all (though it is
the most likely cause) but could result from a global
cache containing references to acquisition wrapped objects.
Such a cache should never exist -- global variables and
class attributes must never directly or indirectly reference
persistent objects -- as this results in nasty persistency bugs.
Nevertheless, sometimes software is buggy. I noticed
such a cache in Archetypes 1.3a2 (fixed in newer versions).
>Said dictionary does not seem to be referred to by anything, at least not
>anything the gc module can find (gc.get_referrers()).
That's probably because "RequestContainer" is an ExtensionClass
and ExtensionClasses are not yet (only from Zope 2.8 on) GC aware.
> ...
>Also I
>understand zope.org suffers from this? :)
Leaks can have innumerable causes. It is by no means clear
that your leak and the one on Zope.org has the same cause.
>Based on this information also, I have no reason to believe this is caused
>by product code ... I have to guess it's a Zope bug?
I do not observe leaks in my Zope installation -- even when
I make an error stress test.
This does not mean it could not be a Zope bug --
but it implies that such a bug does not surface regularly, at most
under special conditions.
>In some ways this is motivating me to reduce the number of errors that could
>occur, but because ALL errors seems to cause the problem, I ultimately have
>no control over it and under certain circumstances I suffer heavily from
>this. 404's alone probably cause this (I'm plannign to test that
>explicitely as well).
It does not here
Something is special with your installation -- maybe "Localizer" as
Tres suggested, maybe another misbehaving product.
--
Dieter
___
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Re: [Zope-dev] Preliminary findings: Zope 2.7 leakage caused by errors
[EMAIL PROTECTED] wrote at 2004-5-19 14:44 -0400: > ... >In following to the discussions regarding the leakage zope.org and my site >suffer from, I've done some testing, and here's what I've found. > >First of all, the leak does seem to occur when errors occur. Unlike what >Chris suggested, I still suffer from this leak even when I completely >remove standard_error_message. I tried to reproduce this behaviour -- but failed. Despite errors and a standard "standard_error_meesage" nothing leaked... -- Dieter ___ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
