[Zope-CMF] is there a conflict error resistent index

Perry js at aixtraware.de
Mon Jun 18 07:56:31 EDT 2007

Dieter Maurer schrieb:
> Joachim Schmitz wrote at 2007-6-16 13:35 +0200:
>> ...
>> during our recent search for the cause of the many conflict errors, we 
>> discovered that nearly all of them where caused during indexing the 
>> portal_catalog, when the same values are indexed. This can happen easily 
>> with date_indexes, since the dates are only stored with a resolution of 
>> 1 minute.
> Usually, this will not cause a conflict -- only when in addition
> the first objects that use a new date value are created
> in concurrent transactions. I expect that the probability is not
> too high for this....
That was certainly the case with the date_indexes. We could get rid of 
those conflict errors by using the QueueCatalog. But still we are 
getting conflict errors on the indexes, we are updating immediatly for 
example the review_state.

>> Even more conflict error prone is the reviewstate. Since there 
>> are only a few reviewstates.
> Again, only the initial "filling" of the document list for
> a given state is critical. Once there is a document list,
> this list (an "IITreeSet", usually) can concurrently add elements
> (using application specific conflict resolution -- reducing the
> conflict probability by a factor of about 120).

I didn't find any application specific conflict resolution in the 
fieldindex ? Are you saying, that once there is one document created 
within a review_state, conflict errors for that review_state are very 
unlikely, even under heavy load.

> For one of our internal projects, I have created a set
> of "conflict reduced indexes". These indexes do not delete
> a document list one it has been created. However, it turned
> out that this additional conflict protection is not worth the effort.
> My special indexes have been phased out meanwhile....


Gruß Joachim

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