feat(rust)!: define cancellation in a sensible way#3905
feat(rust)!: define cancellation in a sensible way#3905lidavidm wants to merge 1 commit intoapache:mainfrom
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lidavidm
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Any concerns here? |
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I started looking at the code and got confused. Are you going to cancel any statement currently running in the connection or do I get one handle per |
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One per statement (the handle has a weak reference to the specific statement) |
abonander
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abonander
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This seems all right, the inheritance can be implemented using tokio_util::sync::CancellationToken::child_token().
Just a few questions about the detailed semantics.
| /// Cancel the in-progress operation on a connection. | ||
| fn try_cancel(&self) -> Result<()>; |
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Are the try_ prefix and the default to NoOpCancellationHandle meant to imply that this is on a best-effort basis only? Can that be more clearly documented?
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It's only sort-of implied by
arrow-adbc/c/include/arrow-adbc/adbc.h
Lines 2130 to 2131 in e8642f8
| /// | ||
| /// This is a separated handle because otherwise it would be impossible to | ||
| /// call a `cancel` method on a connection or statement itself. | ||
| pub trait CancelHandle: Send { |
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arrow-adbc/c/include/arrow-adbc/adbc.h
Lines 2133 to 2134 in e8642f8
"thread-safe" implies that this handle should be Sync as well since there isn't really a distinction between "can be moved between threads" and "can be called concurrently from multiple threads" in C.
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| impl CancelHandle for NoOpCancellationHandle { | ||
| fn try_cancel(&self) -> Result<()> { | ||
| Ok(()) |
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Should the default be to return ADBC_STATUS_UNKNOWN to indicate that the operation cannot be cancelled per
arrow-adbc/c/include/arrow-adbc/adbc.h
Line 2143 in e8642f8
| fn get_cancel_handle(&self) -> Box<dyn CancelHandle> { | ||
| Box::new(NoOpCancellationHandle {}) | ||
| } |
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Are you going to introduce AdbcDatabaseCancel() to the C API? Otherwise I don't see why this needs to exist.
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Closes #3454.