On 28.12.09 18:54 , Kevin Grittner wrote:
To give some idea of the scope of development, Michael Cahill added SSI to InnoDB by modifying 250 lines of code and adding 450 lines of code; however, InnoDB already had the S2PL option and the prototype implementation isn't as sophisticated as I feel is necessary for real production use (particularly regarding the granularity of SIREAD locks). I'm assuming it would take more to reach real production quality in PostgreSQL. My SWAG would be to multiply by two or three.
I believe the hard part of implementing true serializability is not the actual SSI or S2PL algorithm, but rather the necessary predicate locking strategy. So I think checking how InnoDB tackles that and how much of it's code is invovled might give a more realistic estimate of the effort required. best regards, Florian Plug
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