Support multi diskRanges for ChunkReader #1955
Description
Is your feature request related to a problem or challenge? Please describe what you are trying to do.
related to #1775
When i implement page index skipping #1792 , i found
/// The ChunkReader trait generates readers of chunks of a source.
/// For a file system reader, each chunk might contain a clone of File bounded on a given range.
/// For an object store reader, each read can be mapped to a range request.
pub trait ChunkReader: Length + Send + Sync {
type T: Read + Send;
/// get a serialy readeable slice of the current reader
/// This should fail if the slice exceeds the current bounds
fn get_read(&self, start: u64, length: usize) -> Result<Self::T>;
}
it assume read whole column chunk bytes array, but when facing like
* rows col1 col2 col3
* ┌──────┬──────┬──────┐
* 0 │ p0 │ │ │
* ╞══════╡ p0 │ p0 │
* 20 │ p1(X)│------│------│
* ╞══════╪══════╡ │
* 40 │ p2 │ │------│
* ╞══════╡ p1(X)╞══════╡
* 60 │ p3(X)│ │------│
* ╞══════╪══════╡ │
* 80 │ p4 │ │ p1 │
* ╞══════╡ p2 │ │
* 100 │ p5 │ │ │
* └──────┴──────┴──────┘
read col1 page1 and page3 we need skip other pages
we should pass two offsets
Describe the solution you'd like
pass multi strart and length
fn get_read(&self, start: vec<u64>, length: vec<usize>) -> Result<Self::T>;
Describe alternatives you've considered
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Additional context
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