[ZODB-Dev] Re: ZODB Benchmarks

[Godefroid Chapelle]

Jim Fulton wrote:
> 
> On Nov 6, 2007, at 2:40 PM, Sidnei da Silva wrote:
> 
>>> Despite this change there are still a huge amount
>>> of unexplained calls to the 'persistent_id' method of the ObjectWriter
>>> in serialize.py.
>>
>> Why 'unexplained'? 'persistent_id' is called from the Pickler instance
>> being used in ObjectWriter._dump(). It is called for each and every
>> single object reachable from the main object, due to the way Pickler
>> works (I believe). Maybe persistent_id can be analysed and optimized
>> for the most common cases?
> 
> Yup.
> 
> Note that there is a undocumented feature in cPickle that I added years 
> ago to deal with this issue but never got around to pursuing.  Maybe 
> someone else would be able to spend the time to try it out and report back.
> 
> If you set inst_persistent_id, rather than persistent_id, on a pickler, 
> then the hook will only be called for instances.  This should eliminate 
> that vast majority of the calls.
> 
> Note that this feature was added back when testing was minimal or 
> non-existent, so it is untested, however, the implementation is simple 
> enough.  :) 

Do you mean that the ZODB has enough tests now that making the change 
and running the tests might already be a good proof ?

Or should we be more prudent ?

> If it would,

What do you mean by 'If it would' ?

> then of course we should contribute 
> documentation and a test to the Python source tree.
> 
> Jim
> 
> -- 
> Jim Fulton
> Zope Corporation
> 

-- 
Godefroid Chapelle (aka __gotcha) http://bubblenet.be