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

Tres Seaver tseaver at palladion.com
Mon Jun 18 16:01:00 EDT 2007


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Perry wrote:
> 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.

FieldIndex uses persistent subobjects, mostly BTree variants, to manage
its data structures;  those objects, once populated, supply the conflict
resolution.


Tres.
- --
===================================================================
Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFGduR8+gerLs4ltQ4RAoEUAKDGCnnbjcgMi8m9PnRAR3zPnJmNcQCfTnpt
UsTJZxlw1G2QAQk7LwQtZ/E=
=FHIS
-----END PGP SIGNATURE-----



More information about the Zope-CMF mailing list