[Tech] Re: MemoryErrors

[Eli Beckerman]

Not all that helpful, from  http://www.zettai.net/Support/Howto/MemoryErrors

Zope Memory Errors Howto
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When you see a MemoryError on your Zope-based website it means your
Zope instance has hit its hard RAM limit. Zope, and even more so
Plone, can use a lot of RAM and RAM being a limited resource, you can
sometimes get these errors.

Zope and Plone Need Lots of Memory

The first thing you should know is that Zope and and Plone is that
they need a lot of memory. Zope 2.8 and Plone 2.1 just to start will
need nearly 80MB of RAM. That number can easily go much higher once
you start adding new Products.

What to do About MemoryErrors: Short Term

The first thing you should do when you see a Zope MemoryError is
restart your Zope instance. Please follow the instructions below for
your respective account type.

Shared Zope & Plone Accounts: Only support can restart the Zope
instance your account is on. Please wait 5-10 minutes and if the
problem continues, kindly file a support ticket with the details.

Zope Instance and Server Accounts: If you are unable to login to the
ZMI of your Zope and click the Shutdown (Restart) button then login
via ssh and run:

zopectl restart

You can request we put monitors in place that should automatically and
smoothly restart your Zope instance before it hits its RAM limit.
These are already in place for Zope 2.7 instances.

What to do About MemoryErrors: Long Term

After your Zope instance is working again, you will have time to
consider some longer term solutions (these do not apply to shared Zope
& Plone accounts). They include:

Consider upgrading to Zope 2.7.3 or above if you are not already using
it. Zope 2.7.3 patches a memory leak in some previous versions of Zope
and can radically reduce your Zope's RAM usage in some cases.

Upgrade to a more recent version of Zwiki. Some previous versions had
a memory leak.

Remove some Zope Products that you don't need or aren't using. Please
note that its probably not true that Placeless Translation Service
causes Zope to leak memory.

You might try packing your Zope but the effect will surely be very minimal.
Upgrade your Zope Hosting Plan to one that has more RAM - maybe that's
just what your application(s) need.

Related Error: Proxy Error

You may sometimes see a Proxy Error after restarting your Zope, when
Zope is not accepting/responding to requests. This error does not come
from Zope but instead comes from Apache.

If this error persists for more than 5 minutes you should login via
SSH and see if your Zope is down, deadlocked, or why it is not
accepting requests. Perhaps your Zope just needs to be restarted. If
your zope does not respond after you have run 'zopectl restart', then
feel free to file a support ticket with all the relevant details if
you need help at this point.