[Zope] Re: Long transactions and conflict errors

[Tres Seaver]

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Pascal Peregrina wrote:
| Hi,
|
| During a long transaction that reads lots of ZODB objects in order to
| generate a report, I get Conflict Errors, which is not a suprise as other
| users keep accessing some of the same objects.
|
| I would like to know if during a transaction there is a way to "unlock"
| objects from which I read some values but that I don't need anymore
for the
| rest of the transaction execution.

ZODB 3.3 attacks this problem using "multi-version concurrency control",
~ which allows for "generational reads" of objects as they were at the
start of the transaaction.   MVCC eliminates the classic ReadConflict
problem, because all reads are made from a transactionally-consistent
timepoint.

ZODB 3.3 is available from SVN, or as part of one of the Zope 2.8 alphas.

Tres.
- --
===============================================================
Tres Seaver                                tseaver at zope.com
Zope Corporation      "Zope Dealers"       http://www.zope.com
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