[Zope-dev] ZODB Competing read/writes: How to find out which attribute?

Roger Ineichen dev at projekt01.ch
Fri Oct 9 15:44:12 EDT 2009


Hi Hermann

> Betreff: Re: [Zope-dev] ZODB Competing read/writes: How to 
> find out which attribute?
> 
> Hermann Himmelbauer wrote:
> > Hi,
> > I once in the while get the following warning in my Zope 3 
> log, which 
> > I'd like to resolve:
> > 
> > 2009-10-07T14:35:41 WARNING ZopePublication Competing 
> writes/reads at 
> > 
> /BSPSite/act/++vh++http:zis.act.at:80/bankneu/++/c/acc/booklis
t/index.html:
> > database conflict error (oid 0x7a5d, class BTrees.OOBTree.OOBTree, 
> > serial this txn started with 0x0381388ca6804966 2009-10-07 
> > 12:28:39.023700, serial currently committed 0x03813893b087d0cc 
> > 2009-10-07 12:35:41.374343)
> 
> That URL looks like it should only be reading the database, 
> but the fact that you get a conflict error suggests that the 
> code behind that URL is writing to the database.  If I were 
> you, I would first ensure that read operations never write to 
> the database.

just a hint, sometimes session get accessed with session[key]
wich will force a write operation. If so, you can prevent creating
a new session by using session.get(key, someDefaultValue)

Regards
Roger Ineichen

> Shane
> 
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