MsgPack

Description

ClickHouse supports reading and writing MessagePack data files.

Data Types Matching

MessagePack data type (INSERT)	ClickHouse data type	MessagePack data type (SELECT)
uint N, positive fixint	UIntN	uint N
int N, negative fixint	IntN	int N
bool	UInt8	uint 8
fixstr, str 8, str 16, str 32, bin 8, bin 16, bin 32	String	bin 8, bin 16, bin 32
fixstr, str 8, str 16, str 32, bin 8, bin 16, bin 32	FixedString	bin 8, bin 16, bin 32
float 32	Float32	float 32
float 64	Float64	float 64
uint 16	Date	uint 16
int 32	Date32	int 32
uint 32	DateTime	uint 32
uint 64	DateTime64	uint 64
fixarray, array 16, array 32	Array/Tuple	fixarray, array 16, array 32
fixmap, map 16, map 32	Map	fixmap, map 16, map 32
uint 32	IPv4	uint 32
bin 8	String	bin 8
int 8	Enum8	int 8
bin 8	(U)Int128/(U)Int256	bin 8
int 32	Decimal32	int 32
int 64	Decimal64	int 64
bin 8	Decimal128/Decimal256	bin 8

Example Usage

Example:

Writing to a file ".msgpk":

$ clickhouse-client --query="CREATE TABLE msgpack (array Array(UInt8)) ENGINE = Memory;"
$ clickhouse-client --query="INSERT INTO msgpack VALUES ([0, 1, 2, 3, 42, 253, 254, 255]), ([255, 254, 253, 42, 3, 2, 1, 0])";
$ clickhouse-client --query="SELECT * FROM msgpack FORMAT MsgPack" > tmp_msgpack.msgpk;

Format Settings

• input_format_msgpack_number_of_columns - the number of columns in inserted MsgPack data. Used for automatic schema inference from data. Default value - 0.
• output_format_msgpack_uuid_representation - the way how to output UUID in MsgPack format. Default value - EXT.