Greg Stark wrote:
And I don't see why you discard "visibility" as unimportant. All the
transaction isolations are defined in terms of the results if the
transactions. Those results include both the database state and the data
returned by the queries. Otherwise "phantom read" is a meaningless concept.
Basically, if he wants to make a rigid argument that some scenario
violates the serializability promise, then it is necessary to prove:
(1) There is no serial schedule for the set of transactions that
achieves the same outcome. (This proof is probably hard to work out, as
many "there is no" proofs are.)
- or -
(2) A phantom read situation occurs.
His original argument uses terms like "window" where something is
"visible" (to whom?), which can probably be transformed into a proof for
(2), but is not convincing (to me) by itself.
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