Types

Chunk Headers, Timeseries Metadata, and Table Schemas use a single-byte data_type identifier:

Value	Name	Physical or logical meaning
0	BOOLEAN	Boolean value
1	INT32	Signed 32-bit integer
2	INT64	Signed 64-bit integer
3	FLOAT	IEEE 754 binary32
4	DOUBLE	IEEE 754 binary64
5	TEXT	Length-prefixed byte string
6	VECTOR	Physical type marker used by an aligned Time Chunk
7	UNKNOWN	Unknown type marker
8	TIMESTAMP	Signed 64-bit integer; the upper layer defines the time unit
9	DATE	Signed 32-bit integer in decimal YYYYMMDD form
10	BLOB	Arbitrary byte string
11	STRING	UTF-8 string
12	OBJECT	Byte representation of an object value

For example, the physical DATE value for 2026-07-27 is the decimal integer 20260727, not a Unix epoch day.

The data type determines the additional Statistics fields and the input type of the value encoder. See Encodings for wire representations of values.

Physical and Logical Types

A data type describes the value domain; the encoding determines how those values become bytes. TIMESTAMP and DATE also assign a meaning to the underlying integer:

• TIMESTAMP has the same signed 64-bit value domain as INT64. The time unit is supplied by the protocol or dataset using the file; TsFile v4 does not serialize that unit.
• DATE has the same integer encoder interface as INT32, but valid logical values use decimal YYYYMMDD form.
• TEXT is a length-delimited byte string. STRING uses the same physical binary container but has UTF-8 string semantics. BLOB is uninterpreted binary data.
• OBJECT stores object bytes. The applications exchanging the file agree on how to reconstruct an object from them.

VECTOR is a physical marker for the shared time column of aligned data. It is not a scalar value type and does not define a standalone value-stream encoding. UNKNOWN is a sentinel, not a valid type for a decodable measurement Page.

Type Consistency

The same series type is repeated at different levels so a reader can enter the file through the footer or through a sequential scan. These copies must agree:

• A non-aligned or aligned Value Chunk Header uses the measurement's scalar data_type.
• Its Timeseries Metadata uses the same data_type.
• Statistics are decoded using that type and contain no independent type byte.
• An aligned Time Chunk uses VECTOR; its decoded values are signed 64-bit timestamps.

Changing the interpretation of a previously assigned identifier is incompatible. A reader that does not support a type identifier may still skip a complete Chunk using data_size, but it cannot decode values or type-specific Statistics for that series.

Ordering and Comparison

Integer and floating-point values use their numeric order for min/max Statistics. STRING min/max values compare their raw value bytes lexicographically, excluding length prefixes. TEXT stores only first and last values, while BLOB and OBJECT store no type-specific value Statistics.

Type promotion and application-level casts are not encoded in TsFile. A reader can expose such conversions, but they do not change the stored data_type or the bytes used to compute Statistics.