[ZODB-Dev] [ZEO] Storage error with big transactions.

[Jim Fulton]

On Feb 12, 2007, at 12:25 PM, Andreas Jung wrote:

> I have the following script to emulate a long running writing ZEO  
> client
> by writing 100MB to a page template:
>
> import transaction
>
> pt = app.foo
> while 1:
>    data = '*'*100000000
>    T = transaction.begin()
>    pt.pt_edit(data, 'text/html')
>    T.commit()
>    print 'done'
>
> This script fails badly during during the first commit() call. Is  
> this a bug
> or feature? I am using Zope 2.10.2 on MacOSX Intel.

Based on the traceback you gave, this looks like a bug.  I've  
noticed, however, that large database records can lead to memory  
errors at sizes much smaller than I would expect.  If the problem is  
ultimately traced to a hidden memory error, there's not much that can  
be done.  In the long run, I expect we'll advise that "large" objects  
be put in blobs, where "large" might be smaller than one might  
expect.  For example, I've seen 90MB records lead to memory errors  
even on machines with a hundreds of megabytes free.

Jim

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