chaoqin-li1123 opened a new pull request, #45977:
URL: https://github.com/apache/spark/pull/45977
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### What changes were proposed in this pull request?
SimpleDataSourceStreamReader is a simplified version of the
DataSourceStreamReader interface.
There are 3 functions that needs to be defined
1. Read data and return the end offset.
_def read(self, start: Offset) -> (Iterator[Tuple], Offset)_
2. Read data between start and end offset, this is required for exactly once
read.
_def read2(self, start: Offset, end: Offset) -> Iterator[Tuple]_
3. initial start offset of the streaming query.
_def initialOffset() -> dict_
The implementation wrap the SimpleDataSourceStreamReader instance in a
DataSourceStreamReader that prefetch and cache data in latestOffset. The record
prefetched in python process will be sent to JVM as arrow record batches in
planInputPartitions() and cached by block manager.
### Why are the changes needed?
Compared to DataSourceStreamReader interface, the simplified interface has
some advantages.
It doesn’t require developers to reason about data partitioning.
It doesn’t require getting the latest offset before reading data.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Add unit test and integration test.
### Was this patch authored or co-authored using generative AI tooling?
No.
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