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From Michael Dürig <mdue...@apache.org>
Subject Re: [jr3 microkernel] Write skew
Date Thu, 01 Dec 2011 15:20:14 GMT


On 1.12.11 15:10, Jukka Zitting wrote:
>>> If I understand the paper correctly, also this approach requires
>>> synchronization to establish the serialization order of transactions.
>>
>> No I don't think so. What it does is, it cancels problematic transactions.
>> Detecting these requires finding certain read-write conflicts between
>> transactions.
>
> But if there are two concurrent transactions, the commit of the other
> one needs to wait until the first one has been processed before it can
> complete the check against conflicts. Otherwise how can a conflicting
> commit be made to fail?
>

I see, that's right. Unless the other transaction has access to the 
operations of the first transaction. In that case - and if it decides to 
abort due to a conflict and later the first also decides to abort - the 
other transaction would have aborted unnecessarily. That shouldn't hurt 
too much though.

Michael

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