[ZODB-Dev] Re: Concurrent transactions

[Jim Fulton]

On Jun 1, 2007, at 6:07 AM, Kai Diefenbach wrote:

> Stefan H. Holek <stefan at epy.co.at> wrote:
>
>> Counting in the ZODB is more or less a no-go. You will get write
>> conflicts, and your ZODB will grow (too) quickly.

I kind of doubt that updating a little counter will make the database  
grow "too" quickly, but that might depend on how often the counter  
was updated and how you defined "too". :)

An issue with current ZODB storage implementations is that they  
require explicit packing to remove old revisions and, in the case of  
the file storage implementation, packing is rather expensive.  (I  
think the FileStorage pack implementation could be improved quite a  
bit in this regard.) If you have a very busy counter, you might have  
to pack more often then you otherwise would.

> But what's an alternative?

That depends on the underlying use case.  If you want to track  
traffic, there's always log analysis. :)

> In general I don't like the thought to use a RDBMS in parallel to  
> Zope's
> ZODB approach. And more than ever for a counter.

If the counter if updated a lot, then transactional databases,  
including most RDBMSs and ZODB are likely to be too slow, again, for  
some definition of "too".

Jim

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