[ZODB-Dev] How to avoid ConflictErrors in BTrees ?

[Jim Fulton]

On Feb 1, 2008, at 9:49 AM, Tarek Ziadé wrote:

>
>
> Jim Fulton wrote:
>>
>> ...
>>> Since BTrees are written in C, I couldn't add my own conflict
>>> manager to try
>>> to merge buckets. (and this is
>>> way over my head)
>> That doesn't really matter, because conflict-resolution can only
>> operate on one object at a time.
>>
>
> Is the class I have shown to Andreas is the way to go for conflict
> resolution
> (beside the fact that it shouldn't occur with a better design) ?

I doubt it.  I don't want to work that hard.

>
>
>
> Jim Fulton wrote:
>>
>> ..
>> A similar and common mistake is
>> to allocate keys sequentially.  A better solution is to allocate keys
>> randomly (or sequentially within threads with random starting  
>> points).
>>
>
> Is it possible to have some kind of thread-safe next_id() function ?
> like what some database systems provides


There are numerous examples of this. It isn't provided by ZODB because  
this is an application issue.  Look at the way ids are generated in  
the Zope 3 intid utility and in the Zope 2 catalog.

Jim

--
Jim Fulton
Zope Corporation