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{ “title”: “Export Overview”, “language”: “en”, “description”: “The data export function is used to write the query result set or Doris table data into the specified storage system in the specified file format.” }

The data export function is used to write the query result set or Doris table data into the specified storage system in the specified file format.

The differences between the export function and the data backup function are as follows:

	Data Export	Data Backup
Final Storage Location	HDFS, Object Storage, Local File System	HDFS, Object Storage
Data Format	Open file formats such as Parquet, ORC, CSV	Doris internal storage format
Execution Speed	Moderate (requires reading data and converting to the target data format)	Fast (no parsing and conversion required, directly upload Doris data files)
Flexibility	Can flexibly define the data to be exported through SQL statements	Only supports table-level full backup
Use Cases	Result set download, data exchange between different systems	Data backup, data migration between Doris clusters

Choosing Export Methods

Doris provides three different data export methods:

• SELECT INTO OUTFILE: Supports the export of any SQL result set.
• EXPORT: Supports the export of partial or full table data.
• MySQL DUMP: Compatible with the MySQL dump command for data export.

The similarities and differences between the three export methods are as follows:

	SELECT INTO OUTFILE	EXPORT	MySQL DUMP
Synchronous/Asynchronous	Synchronous	Asynchronous (submit EXPORT tasks and check task progress via SHOW EXPORT command)	Synchronous
Supports any SQL	Yes	No	No
Export specific partitions	Yes	Yes	No
Export specific tablets	Yes	No	No
Concurrent export	Supported with high concurrency (depends on whether the SQL statement has operators such as ORDER BY that need to be processed on a single node)	Supported with high concurrency (supports tablet-level concurrent export)	Not supported, single-threaded export only
Supported export data formats	Parquet, ORC, CSV	Parquet, ORC, CSV	MySQL Dump proprietary format
Supports exporting external tables	Yes	Partially supported	No
Supports exporting views	Yes	Yes	Yes
Supported export locations	S3, HDFS	S3, HDFS	LOCAL

SELECT INTO OUTFILE

Suitable for the following scenarios:

• Data needs to be exported after complex calculations, such as filtering, aggregation, joins, etc.
• Suitable for scenarios that require synchronous tasks.

EXPORT

Suitable for the following scenarios:

• Large-scale single table export, with simple filtering conditions.
• Scenarios that require asynchronous task submission.

MySQL Dump

Suitable for the following scenarios:

• Compatible with the MySQL ecosystem, requires exporting both table structure and data.
• Only for development testing or scenarios with very small data volumes.

Export File Column Type Mapping

Parquet and ORC file formats have their own data types. Doris‘s export function can automatically map Doris’s data types to the corresponding data types in Parquet and ORC file formats. The CSV format does not have types, all data is output as text.

The following table shows the mapping between Doris data types and Parquet, ORC file format data types:

• ORC

  Doris Type	Orc Type
  boolean	boolean
  tinyint	tinyint
  smallint	smallint
  int	int
  bigint	bigint
  largeInt	string
  date	string
  datev2	string
  datetime	string
  datetimev2	timestamp
  float	float
  double	double
  char / varchar / string	string
  decimal	decimal
  struct	struct
  map	map
  array	array
  json	string
  variant	string
  bitmap	binary
  quantile_state	binary
  hll	binary

• Parquet

  When Doris is exported to the Parquet file format, the Doris memory data is first converted to the Arrow memory data format, and then written out to the Parquet file format by Arrow.

  Doris Type	Arrow Type	Parquet Physical Type	Parquet Logical Type
  boolean	boolean	BOOLEAN
  tinyint	int8	INT32	INT_8
  smallint	int16	INT32	INT_16
  int	int32	INT32	INT_32
  bigint	int64	INT64	INT_64
  largeInt	utf8	BYTE_ARRAY	UTF8
  date	utf8	BYTE_ARRAY	UTF8
  datev2	date32	INT32	DATE
  datetime	utf8	BYTE_ARRAY	UTF8
  datetimev2	timestamp	INT96/INT64	TIMESTAMP(MICROS/MILLIS/SECONDS)
  float	float32	FLOAT
  double	float64	DOUBLE
  char / varchar / string	utf8	BYTE_ARRAY	UTF8
  decimal	decimal128	FIXED_LEN_BYTE_ARRAY	DECIMAL(scale, precision)
  struct	struct		Parquet Group
  map	map		Parquet Map
  array	list		Parquet List
  json	utf8	BYTE_ARRAY	UTF8
  variant	utf8	BYTE_ARRAY	UTF8
  bitmap	binary	BYTE_ARRAY
  quantile_state	binary	BYTE_ARRAY
  hll	binary	BYTE_ARRAY

  Note: In versions 2.1.11 and 3.0.7, you can specify the parquet.enable_int96_timestamps property to determine whether Doris‘s datetimev2 type uses Parquet’s INT96 storage or INT64. INT96 is used by default. However, INT96 has been deprecated in the Parquet standard and is only used for compatibility with some older systems (such as versions before Hive 4.0).