
Sequential Consistency in Practice - ldelossa
https://www.ldelossa.is/blog/sequential-consistency-in-practice
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grogers
> Proc-3 Observes: W(x),W(z),W(y), R() => y

> Proc-4 Observes: W(y),W(x),W(z), R() => z

Sequential consistency implies a total order on writes, not just that
processes see the writes in an order consistent with the order each individual
writer used. This history is not valid according to sequential consistency. It
_IS_ valid for the two processors to see different values, if one read is
stale, but it wouldn't see a different order of writes.

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ldelossa
Hello Grogers,

Thank you for the feedback. When reading the literature I came to the
impression that a single processor need not agree with others on which valid
interleaving is observed. I could be wrong about this. Can you provide me any
sources that helped you come to your conclusion? I will read thru and edit the
post accordingly.

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ldelossa
a quick post clearing up what sequential consistency looks like in distributed
systems.

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lukevp
Should valid example 2 be y x z? I don’t understand the 2 y write processing
so if I misinterpreted this, I would appreciate it if you could explain in
more detail.

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ReactiveJelly
Yeah, looks like a typo. There should be 3 valid order: xzy, xyz, and yxz, if
I understood the premise right.

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ldelossa
yes, fixed. thanks!

