Github user HyukjinKwon commented on a diff in the pull request: https://github.com/apache/spark/pull/23266#discussion_r240073831 --- Diff: sql/core/src/main/java/org/apache/spark/sql/sources/v2/SupportsBatchRead.java --- @@ -20,14 +20,27 @@ import org.apache.spark.annotation.Evolving; import org.apache.spark.sql.sources.v2.reader.Scan; import org.apache.spark.sql.sources.v2.reader.ScanBuilder; +import org.apache.spark.sql.types.StructType; /** - * An empty mix-in interface for {@link Table}, to indicate this table supports batch scan. - * <p> - * If a {@link Table} implements this interface, its {@link Table#newScanBuilder(DataSourceOptions)} - * must return a {@link ScanBuilder} that builds {@link Scan} with {@link Scan#toBatch()} - * implemented. - * </p> + * A mix-in interface for {@link Table} to provide data reading ability of batch processing. */ @Evolving -public interface SupportsBatchRead extends Table { } +public interface SupportsBatchRead extends Table { + + /** + * Returns the schema of this table. + */ + StructType schema(); + + /** + * Returns a {@link ScanBuilder} which can be used to build a {@link Scan} later. The built + * {@link Scan} must implement {@link Scan#toBatch()}. Spark will call this method for each data + * scanning query. + * <p> + * The builder can take some query specific information to do operators pushdown, and keep these + * information in the created {@link Scan}. + * </p> + */ + ScanBuilder newScanBuilder(DataSourceOptions options); --- End diff -- +1
--- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org