Add more debug logging for CloudFetch (#227)

Signed-off-by: Levko Kravets <levko.ne@gmail.com>

Author: kravets-levko

internal/rows/arrowbased/arrowRows.go

@@ -115,7 +115,12 @@ func NewArrowRowScanner(resultSetMetadata *cli_service.TGetResultSetMetadataResp
 	var bl BatchLoader
 	var err2 dbsqlerr.DBError
 	if len(rowSet.ResultLinks) > 0 {
+		logger.Debug().Msgf("Initialize CloudFetch loader, row set start offset: %d, file list:", rowSet.StartRowOffset)
+		for _, resultLink := range rowSet.ResultLinks {
+			logger.Debug().Msgf("- start row offset: %d, row count: %d", resultLink.StartRowOffset, resultLink.RowCount)
+		}
 		bl, err2 = NewCloudBatchLoader(context.Background(), rowSet.ResultLinks, rowSet.StartRowOffset, cfg)
+		logger.Debug().Msgf("Created CloudFetch concurrent loader, rows range [%d..%d]", bl.Start(), bl.End())
 	} else {
 		bl, err2 = NewLocalBatchLoader(context.Background(), rowSet.ArrowBatches, rowSet.StartRowOffset, schemaBytes, cfg)
 	}

internal/rows/arrowbased/batchloader.go

@@ -18,6 +18,7 @@ import (
 	"github.com/databricks/databricks-sql-go/internal/cli_service"
 	dbsqlerrint "github.com/databricks/databricks-sql-go/internal/errors"
 	"github.com/databricks/databricks-sql-go/internal/fetcher"
+	"github.com/databricks/databricks-sql-go/logger"
 )
 
 type BatchIterator interface {
@@ -126,15 +127,22 @@ var _ BatchLoader = (*batchLoader[*localBatch])(nil)
 
 func (cbl *batchLoader[T]) GetBatchFor(rowNumber int64) (SparkArrowBatch, dbsqlerr.DBError) {
 
+	logger.Debug().Msgf("batchLoader.GetBatchFor(%d)", rowNumber)
+
 	for i := range cbl.arrowBatches {
+		logger.Debug().Msgf("  trying batch for range [%d..%d]", cbl.arrowBatches[i].Start(), cbl.arrowBatches[i].End())
 		if cbl.arrowBatches[i].Contains(rowNumber) {
+			logger.Debug().Msgf("  found batch containing the requested row %d", rowNumber)
 			return cbl.arrowBatches[i], nil
 		}
 	}
 
+	logger.Debug().Msgf("  batch not found, trying to download more")
+
 	batchChan, _, err := cbl.fetcher.Start()
 	var emptyBatch SparkArrowBatch
 	if err != nil {
+		logger.Debug().Msgf("  no batch found for row %d", rowNumber)
 		return emptyBatch, dbsqlerrint.NewDriverError(cbl.ctx, errArrowRowsInvalidRowNumber(rowNumber), err)
 	}
 
@@ -143,17 +151,22 @@ func (cbl *batchLoader[T]) GetBatchFor(rowNumber int64) (SparkArrowBatch, dbsqle
 		if !ok {
 			err := cbl.fetcher.Err()
 			if err != nil {
+				logger.Debug().Msgf("  no batch found for row %d", rowNumber)
 				return emptyBatch, dbsqlerrint.NewDriverError(cbl.ctx, errArrowRowsInvalidRowNumber(rowNumber), err)
 			}
 			break
 		}
 
 		cbl.arrowBatches = append(cbl.arrowBatches, batch)
+		logger.Debug().Msgf("  trying newly downloaded batch for range [%d..%d]", batch.Start(), batch.End())
 		if batch.Contains(rowNumber) {
+			logger.Debug().Msgf("  found batch containing the requested row %d", rowNumber)
 			return batch, nil
 		}
 	}
 
+	logger.Debug().Msgf("  no batch found for row %d", rowNumber)
+
 	return emptyBatch, dbsqlerrint.NewDriverError(cbl.ctx, errArrowRowsInvalidRowNumber(rowNumber), err)
 }