gabotechs opened a new pull request, #19759:
URL: https://github.com/apache/datafusion/pull/19759
## Which issue does this PR close?
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- Closes #.
## Rationale for this change
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Why are you proposing this change? If this is already explained clearly in
the issue then this section is not needed.
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Even if the api on the `MemoryPool` does not require `&mut self` for
growing/shrinking the reserved size, the api on `MemoryReservation` does,
making simple implementations irrepresentable without synchronization
primitives. For example, the following would require a `Mutex` for concurrent
access to the `MemoryReservation` in different threads, even though the
`MemoryPool` doesn't:
```rust
let mut stream: SendableRecordBatchStream = SendableRecordBatchStream::new();
let mem: Arc<MemoryReservation> = Arc::new(MemoryReservation::new_empty());
let mut builder = ReceiverStreamBuilder::new(10);
let tx = builder.tx();
{
let mem = mem.clone();
builder.spawn(async move {
while let Some(msg) = stream.next().await {
mem.try_grow(msg.unwrap().get_array_memory_size());
tx.send(msg).unwrap();
}
});
}
builder
.build()
.inspect_ok(|msg| mem.shrink(msg.get_array_memory_size()));
```
## What changes are included in this PR?
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There is no need to duplicate the description in the issue here but it is
sometimes worth providing a summary of the individual changes in this PR.
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Make the methods in `MemoryReservation` require `&self` instead of `&mut
self` for allowing concurrent shrink/grows from different tasks for the same
reservation.
## Are these changes tested?
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2. Serve as another way to document the expected behavior of the code
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they covered by existing tests)?
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yes, by current tests
## Are there any user-facing changes?
Users can now safely call methods of `MemoryReservation` from different
tasks without synchronization primitives.
This is a backwards compatible API change, as it will work out of the box
for current users, however, depending on their clippy configuration, they might
see some new warnings about "unused muts" in their codebase.
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updated before approving the PR.
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