[Dev] ZODB for object persistence [Was: ZODB is not a Storage Technology]

[Jeremy Hylton]

>>>>> "JA" == John Anderson <john@osafoundation.org> writes:

  JA> My test program for object creation using ZODB4 goes from
  JA> somewhere around 20,000 objects created per second to 300 per
  JA> second once you throw in transactions. I'd like to use
  JA> transactions for undo and resource exaustion recovery.

How did you throw in transactions?  If, for example, you added a
commit after every object creation, I think I'd be happy if you could
achieve 300 creations/sec <0.3 wink>.

A transaction is a relatively heavyweight operation and object
creation is an incredibly lightweight operation.  I'm sure transaction
commits can be optimized, but it's still going to be a big hit if you
use very fine-grained transactions.  Do you think that's necessary for
you application?

I'd also note that important parts of ZODB4, notably the object cache,
are still using throw-away code written in Python.  There's a reason
we haven't released ZODB4 yet.  For the Dec. alpha release, we'll have
an object cache written in C that should improve performance.  If
you're looking to benchmark code, ZODB 3.1 will give you more
realistic numbers.

Jeremy

PS My own crude benchmark (creation an object passing two args to
__init__) was:

classic class      118000 creations/sec
new-style class     66700 creations/sec
Persistent class      181 create+commit/sec (using FileStorage)