[ZODB-Dev] Re: ReadConflictError while re-indexing big fat index

[Jim Fulton]

Chris Withers wrote:
> Casey Duncan wrote:
> 
>>> 1. What is the above error message really trying to tell me?
>>>    (it's a pretty obscure message ;-)
>>
>>
>> It is telling you that an ISet object in the PathIndex was changed and
>> commited by another client since the transaction began. In order to
>> protect data integrity, ZODB does not allow such "dirty reads", instead
>> it raises a ReadConflict error.
> 
> 
> Heh, now that I finally understand this, it seems like ZODB isn't as 
> perfect as I thought ;-) You kinda take this stuff for granted with any 
> RDB, the I in ACID and all that...

It is not uncommon for databases to about transactions to provide isolation.
The important property here is that one transactions execution is not
affected by another transaction that commits while the first one
is executing.

Jim


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