Result Type Support

HarborSQL encodes Databricks SQL connector result pages directly from Arrow arrays. The current Thrift result type matrix is explicit:

Arrow/DataFusion type	Databricks type metadata	Thrift value representation
Boolean	boolean	boolean
Int8	tinyint	int
Int16	smallint	int
Int32	int	int
Int64, UInt8, UInt16, UInt32	bigint	bigint
UInt64	bigint	bigint only when the value fits in signed i64
Float32	float	double
Float64	double	double
Utf8, LargeUtf8, Utf8View	string	string
Date32, Date64	date	string
Timestamp	timestamp	string
Binary, LargeBinary, FixedSizeBinary	binary	binary
Decimal128, Decimal256	decimal with precision/scale qualifiers	string
List, LargeList, FixedSizeList	array	string
Map	map	string
Struct	struct	string

Decimal and nested values are rendered in the compact Databricks-style display form expected by connector compatibility tests. Arrays render as bracketed values, maps and structs render as JSON-like objects, string values are quoted, and nested date/timestamp values use Databricks-style textual dates and timestamps.

Unsupported Arrow types, including interval, dictionary, duration, list views, and time-only values, return UNSUPPORTED_RESULT_TYPE instead of being coerced.

Query Surface

The default runtime is intentionally read-only. It targets SELECT workloads against Unity Catalog Delta tables and does not currently provide Cloud Fetch, durable result storage, streaming result storage, or broad Databricks SQL protocol coverage.