diff --git a/rust/lancedb/src/remote/table.rs b/rust/lancedb/src/remote/table.rs index 16c546147..d43bab9db 100644 --- a/rust/lancedb/src/remote/table.rs +++ b/rust/lancedb/src/remote/table.rs @@ -3101,7 +3101,13 @@ impl BaseTable for RemoteTable { // loop can re-execute the plan (and re-stream the body) on each retry. // This mirrors the old `send_streaming(with_retry=true)` path, which // likewise buffered the reader to support retries. - let batches = new_data.collect::, _>>()?; + let schema = RecordBatchReader::schema(new_data.as_ref()); + let mut batches = new_data.collect::, _>>()?; + // An empty reader still carries a schema. Keep it in an empty batch so + // the buffered source remains scannable and can be replayed on retries. + if batches.is_empty() { + batches.push(RecordBatch::new_empty(schema)); + } let source: Box = Box::new(batches); let rescannable = source.rescannable(); let input: Arc = @@ -4801,6 +4807,104 @@ mod tests { } } + #[rstest] + #[case::no_batches_insert(false, false)] + #[case::empty_batch_insert(true, false)] + #[case::no_batches_delete(false, true)] + #[case::empty_batch_delete(true, true)] + #[tokio::test] + async fn test_merge_insert_empty_source( + #[case] has_batch: bool, + #[case] delete_unmatched: bool, + ) { + let mut fields = vec![Field::new("id", DataType::Int64, false)]; + if !delete_unmatched { + fields.extend([ + Field::new("k", DataType::Int64, false), + Field::new( + "vector", + DataType::FixedSizeList( + Arc::new(Field::new("item", DataType::Float32, true)), + 2, + ), + true, + ), + Field::new("s", DataType::Utf8, true), + ]); + } + let schema = Arc::new(Schema::new_with_metadata( + fields, + HashMap::from([("source".to_string(), "empty".to_string())]), + )); + let batches = if has_batch { + vec![Ok(RecordBatch::new_empty(schema.clone()))] + } else { + vec![] + }; + let data: Box = + Box::new(RecordBatchIterator::new(batches, schema.clone())); + let attempts = Arc::new(AtomicUsize::new(0)); + let attempts_ref = attempts.clone(); + let num_deleted_rows = if delete_unmatched { 3 } else { 0 }; + + let table = Table::new_with_handler("my_table", move |request| { + assert_eq!(request.method(), "POST"); + assert_eq!(request.url().path(), "/v1/table/my_table/merge_insert/"); + assert_eq!(request.headers()[CONTENT_TYPE], ARROW_STREAM_CONTENT_TYPE); + let params = request.url().query_pairs().collect::>(); + assert_eq!(params["on"], "id"); + assert_eq!( + params["when_not_matched_insert_all"], + (!delete_unmatched).to_string() + ); + assert_eq!( + params["when_not_matched_by_source_delete"], + delete_unmatched.to_string() + ); + + let body = request.body().unwrap().as_bytes().unwrap(); + let reader = StreamReader::try_new(Cursor::new(body), None).unwrap(); + assert_eq!(reader.schema(), schema); + for batch in reader { + assert_eq!(batch.unwrap().num_rows(), 0); + } + + // The empty source must retain its schema when replayed after a conflict. + if attempts_ref.fetch_add(1, Ordering::SeqCst) == 0 { + http::Response::builder() + .status(409) + .body(String::new()) + .unwrap() + } else { + http::Response::builder() + .status(200) + .body( + json!({ + "version": 43, + "num_deleted_rows": num_deleted_rows, + "num_inserted_rows": 0, + "num_updated_rows": 0, + }) + .to_string(), + ) + .unwrap() + } + }); + + let mut merge = table.merge_insert(&["id"]); + if delete_unmatched { + merge.when_not_matched_by_source_delete(None); + } else { + merge.when_not_matched_insert_all(); + } + let result = merge.execute(data).await.unwrap(); + assert_eq!(attempts.load(Ordering::SeqCst), 2); + assert_eq!(result.version, 43); + assert_eq!(result.num_deleted_rows, num_deleted_rows); + assert_eq!(result.num_inserted_rows, 0); + assert_eq!(result.num_updated_rows, 0); + } + #[tokio::test] async fn test_merge_insert_composite_key() { let batch = RecordBatch::try_new(