[ZODB-Dev] deadlock prevention for ZODB3 / Zope 2.6

[Jeremy Hylton]

>>>>> "BAH" == Bakhtiar A Hamid <Bakhtiar> writes:

  BAH> http://lists.zope.org/pipermail/zodb-dev/2002-November/003671.html
  BAH> ref the link

  BAH> while trying out zope2.6 from cvs branch, i got a lot of
  BAH> messages that refers to "missing sortKey() at psycopgDA
  BAH> instance"

  BAH> a Q at #zope later, SteaveA pointed me to the above links.  Q -
  BAH> will this be in the next 2.6.1 release?  coz i think this will
  BAH> break a lot of DAs (as zopezen pointed out at #zope)

We intend to include this change in Zope 2.6.1.  Note that the log
message warns of a potential problem, but nothing should actually
break.  It looks like ZPsycdopgDA's data manager (_p_jar) inherits
from Shared.DC.ZRDB.TM.  It may be necessary to add a sortKey() method
to this base class.  

My one worry is that it probably isn't possible to pick a good
sortKey() in the base class.  But maybe the DA's don't use Python
locks around the 2PC, in which case it doesn't really matter.  If
anyone can say more about what kind of locking is done by DAs, that
would help.

Jeremy