Dataflow: Improve standard order through easier type check elimination. #9134
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aschackmull
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MathiasVP
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May 12, 2022
| * tracked object. The final type indicates the type of the tracked object. | ||
| */ | ||
| abstract private class AccessPath extends TAccessPath { | ||
| private class AccessPath extends TAccessPath { |
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Can I conclude from this that when I'm creating a QL class that wraps an IPA type, it's better (from the compiler's point of view) to make the type non-abstract? Or is there something special about the AccessPath type that means I can't apply this in general?
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Yes, you can indeed conclude that.
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A candidate for a QL4QL query.
hvitved
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May 12, 2022
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Semantically this is a noop, but making
AccessPathmore obviously equal toTAccessPathmeans that the optimiser is able to eliminate a bunch of type checks that otherwise interferes badly with the join order in the standard order inpathStep(they cause the usual prev-before-delta mess).