RE: Global snapshots - Mailing list pgsql-hackers

Hello, Andrey-san, all,


Based on the request at HighGo's sharding meeting, I'm re-sending the information on Commitment Ordering that could be
usedfor global visibility.  Their patents have already expired.
 



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Have anyone examined the following Multiversion Commitment Ordering (MVCO)?  Although I haven't understood this yet, it
insiststhat no concurrency control information including timestamps needs to be exchanged among the cluster nodes.  I'd
appreciateit if someone could give an opinion.
 



Commitment Ordering Based Distributed Concurrency Control for Bridging Single and Multi Version Resources.
 Proceedings of the Third IEEE International Workshop on Research Issues on Data Engineering: Interoperability in
MultidatabaseSystems (RIDE-IMS), Vienna, Austria, pp. 189-198, April 1993. (also DEC-TR 853, July 1992)
 
https://ieeexplore.ieee.org/document/281924?arnumber=281924



The author of the above paper, Yoav Raz, seems to have had strong passion at least until 2011 about making people
believethe mightiness of Commitment Ordering (CO) for global serializability.  However, he complains (sadly) that
almostall researchers ignore his theory, as written in his following  site and wikipedia page for Commitment Ordering.
Doesanyone know why CO is ignored?
 


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* Or, maybe we can use the following Commitment ordering that doesn't require the timestamp or any other information to
betransferred among the cluster nodes.  However, this seems to have to track the order of read and write operations
amongconcurrent transactions to ensure the correct commit order, so I'm not sure about the performance.  The MVCO paper
seemsto present the information we need, but I haven't understood it well yet (it's difficult.)  Could you anybody
kindlyinterpret this?
 



Commitment ordering (CO) - yoavraz2
https://sites.google.com/site/yoavraz2/the_principle_of_co



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Could you please try interpreting MVCO and see if we have any hope in this?  This doesn't fit in my small brain.  I'll
catchup with understanding this when I have time.
 



MVCO - Technical report - IEEE RIDE-IMS 93 (PDF; revised version of DEC-TR 853)
https://sites.google.com/site/yoavraz2/MVCO-WDE.pdf



MVCO is a multiversion member of Commitment Ordering algorithms described below:



Commitment ordering (CO) - yoavraz2
https://sites.google.com/site/yoavraz2/the_principle_of_co



Commitment ordering - Wikipedia
https://en.wikipedia.org/wiki/Commitment_ordering



Related patents are as follows.  The last one is MVCO.



US5504900A - Commitment ordering for guaranteeing serializability across distributed transactions
https://patents.google.com/patent/US5504900A/en?oq=US5504900



US5504899A - Guaranteeing global serializability by applying commitment ordering selectively to global transactions
https://patents.google.com/patent/US5504899A/en?oq=US5504899



US5701480A - Distributed multi-version commitment ordering protocols for guaranteeing serializability during
transactionprocessing
 
https://patents.google.com/patent/US5701480A/en?oq=US5701480


Regards
Takayuki Tsunakawa