OUTFILE

OUTFILE

Name

OUTFILE

description

This statement is used to export query results to a file using the SELECT INTO OUTFILE command. Currently, it supports exporting to remote storage, such as HDFS, S3, BOS, COS (Tencent Cloud), through the Broker process, S3 protocol, or HDFS protocol.

grammar:

query_stmt
INTO OUTFILE "file_path"
[format_as]
[properties]

illustrate:

1. file_path

   filepath points to the path where the file is stored and the file prefix. Such as `hdfs://path/to/my_file`.

   The final filename will consist of `my_file_`, the file number and the file format suffix. The file serial number starts from 0, and the number is the number of files to be divided. Such as:
   
   my_file_abcdefg_0.csv
   my_file_abcdefg_1.csv
   my_file_abcdegf_2.csv

   You can also omit the file prefix and specify only the file directory, such as: hdfs://path/to/

2. format_as

   FORMAT AS CSV

   Specifies the export format. Supported formats include CSV, PARQUET, CSV_WITH_NAMES, CSV_WITH_NAMES_AND_TYPES and ORC. Default is CSV.

   Note: PARQUET, CSV_WITH_NAMES, CSV_WITH_NAMES_AND_TYPES, and ORC are supported starting in version 1.2 .

3. properties

   Specify related properties. Currently exporting via the Broker process, S3 protocol, or HDFS protocol is supported.

   grammar:
   [PROPERTIES ("key"="value", ...)]
   The following properties are supported:
   
   File related properties
       column_separator: column separator,is only for CSV format. mulit-bytes is supported starting in version 1.2, such as: "\\x01", "abc".
       line_delimiter: line delimiter,is only for CSV format. mulit-bytes supported starting in version 1.2, such as: "\\x01", "abc".
       max_file_size: the size limit of a single file, if the result exceeds this value, it will be cut into multiple files, the value range of max_file_size is [5MB, 2GB] and the default is 1GB. (When specified that the file format is ORC, the size of the actual division file will be a multiples of 64MB, such as: specify max_file_size = 5MB, and actually use 64MB as the division; specify max_file_size = 65MB, and will actually use 128MB as cut division points.)
       delete_existing_files: default `false`. If it is specified as true, you will first delete all files specified in the directory specified by the file_path, and then export the data to the directory.For example: "file_path" = "/user/tmp", then delete all files and directory under "/user/"; "file_path" = "/user/tmp/", then delete all files and directory under "/user/tmp/" 
       file_suffix: Specify the suffix of the export file. If this parameter is not specified, the default suffix for the file format will be used.
   
   Broker related properties need to be prefixed with `broker.`:
       broker.name: broker name
       broker.hadoop.security.authentication: specify the authentication method as kerberos
       broker.kerberos_principal: specifies the principal of kerberos
       broker.kerberos_keytab: specifies the path to the keytab file of kerberos. The file must be the absolute path to the file on the server where the broker process is located. and can be accessed by the Broker process
   
   HDFS related properties:
       fs.defaultFS: namenode address and port
       hadoop.username: hdfs username
       dfs.nameservices: if hadoop enable HA, please set fs nameservice. See hdfs-site.xml
       dfs.ha.namenodes.[nameservice ID]：unique identifiers for each NameNode in the nameservice. See hdfs-site.xml
       dfs.namenode.rpc-address.[nameservice ID].[name node ID]: the fully-qualified RPC address for each NameNode to listen on. See hdfs-site.xml
       dfs.client.failover.proxy.provider.[nameservice ID]：the Java class that HDFS clients use to contact the Active NameNode, usually it is org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider
   
       For a kerberos-authentication enabled Hadoop cluster, additional properties need to be set:
       dfs.namenode.kerberos.principal: HDFS namenode service principal
       hadoop.security.authentication: kerberos
       hadoop.kerberos.principal: the Kerberos pincipal that Doris will use when connectiong to HDFS.
       hadoop.kerberos.keytab: HDFS client keytab location.
   
   For the S3 protocol, you can directly execute the S3 protocol configuration:
   s3.endpoint
   s3.access_key
   s3.secret_key
   s3.region
   use_path_style: (optional) default false . The S3 SDK uses the virtual-hosted style by default. However, some object storage systems may not be enabled or support virtual-hosted style access. At this time, we can add the use_path_style parameter to force the use of path style access method.

   Note that to use the delete_existing_files parameter, you also need to add the configuration enable_delete_existing_files = true to the fe.conf file and restart the FE. Only then will the delete_existing_files parameter take effect. Setting delete_existing_files = true is a dangerous operation and it is recommended to only use it in a testing environment.

4. Data Types for Export

   All file formats support the export of basic data types, while only csv/orc/csv_with_names/csv_with_names_and_types currently support the export of complex data types (ARRAY/MAP/STRUCT). Nested complex data types are not supported.

5. Concurrent Export

   Setting the session variable set enable_parallel_outfile = true; enables concurrent export using outfile. For detailed usage, see Export Query Result.

6. Export to Local

   To export to a local file, you need configure enable_outfile_to_local=true in fe.conf.

   select * from tbl1 limit 10 
   INTO OUTFILE "file:///home/work/path/result_";

DataType Mapping

Parquet and ORC file formats have their own data types. The export function of Doris can automatically export the Doris data types to the corresponding data types of the Parquet/ORC file format. The following are the data type mapping relationship of the Doris data types and the Parquet/ORC file format data types:

1. The mapping relationship between the Doris data types to the ORC data types is:

   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

2. When Doris exports data to the Parquet file format, the Doris memory data will be converted to Arrow memory data format first, and then the paraquet file format is written by Arrow. The mapping relationship between the Doris data types to the ARROW data types is:

   Doris Type	Arrow Type
   boolean	boolean
   tinyint	int8
   smallint	int16
   int	int32
   bigint	int64
   largeInt	utf8
   date	utf8
   datev2	utf8
   datetime	utf8
   datetimev2	utf8
   float	float32
   double	float64
   char / varchar / string	utf8
   decimal	decimal128
   struct	struct
   map	map
   array	list

example

1. Use the broker method to export, and export the simple query results to the file hdfs://path/to/result.txt. Specifies that the export format is CSV. Use my_broker and set kerberos authentication information. Specify the column separator as , and the row separator as \n.

   SELECT * FROM tbl
   INTO OUTFILE "hdfs://path/to/result_"
   FORMAT AS CSV
   PROPERTIES
   (
       "broker.name" = "my_broker",
       "broker.hadoop.security.authentication" = "kerberos",
       "broker.kerberos_principal" = "doris@YOUR.COM",
       "broker.kerberos_keytab" = "/home/doris/my.keytab",
       "column_separator" = ",",
       "line_delimiter" = "\n",
       "max_file_size" = "100MB"
   );

   If the final generated file is not larger than 100MB, it will be: result_0.csv. If larger than 100MB, it may be result_0.csv, result_1.csv, ....

2. Export the simple query results to the file hdfs://path/to/result.parquet. Specify the export format as PARQUET. Use my_broker and set kerberos authentication information.

   SELECT c1, c2, c3 FROM tbl
   INTO OUTFILE "hdfs://path/to/result_"
   FORMAT AS PARQUET
   PROPERTIES
   (
       "broker.name" = "my_broker",
       "broker.hadoop.security.authentication" = "kerberos",
       "broker.kerberos_principal" = "doris@YOUR.COM",
       "broker.kerberos_keytab" = "/home/doris/my.keytab"
   );

3. Export the query result of the CTE statement to the file hdfs://path/to/result.txt. The default export format is CSV. Use my_broker and set hdfs high availability information. Use the default row and column separators.

   WITH
   x1 AS
   (SELECT k1, k2 FROM tbl1),
   x2 AS
   (SELECT k3 FROM tbl2)
   SELEC k1 FROM x1 UNION SELECT k3 FROM x2
   INTO OUTFILE "hdfs://path/to/result_"
   PROPERTIES
   (
       "broker.name" = "my_broker",
       "broker.username"="user",
       "broker.password"="passwd",
       "broker.dfs.nameservices" = "my_ha",
       "broker.dfs.ha.namenodes.my_ha" = "my_namenode1, my_namenode2",
       "broker.dfs.namenode.rpc-address.my_ha.my_namenode1" = "nn1_host:rpc_port",
       "broker.dfs.namenode.rpc-address.my_ha.my_namenode2" = "nn2_host:rpc_port",
       "broker.dfs.client.failover.proxy.provider" = "org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider"
   );

   If the final generated file is not larger than 1GB, it will be: result_0.csv. If larger than 1GB, it may be result_0.csv, result_1.csv, ....

4. Export the query result of the UNION statement to the file bos://bucket/result.txt. Specify the export format as PARQUET. Use my_broker and set hdfs high availability information. The PARQUET format does not require a column delimiter to be specified. After the export is complete, an identity file is generated.

   SELECT k1 FROM tbl1 UNION SELECT k2 FROM tbl1
   INTO OUTFILE "bos://bucket/result_"
   FORMAT AS PARQUET
   PROPERTIES
   (
       "broker.name" = "my_broker",
       "broker.bos_endpoint" = "http://bj.bcebos.com",
       "broker.bos_accesskey" = "xxxxxxxxxxxxxxxxxxxxxxxxxxx",
       "broker.bos_secret_accesskey" = "yyyyyyyyyyyyyyyyyyyyyyyyy"
   );

5. Export the query result of the select statement to the file s3a://${bucket_name}/path/result.txt. Specify the export format as csv. After the export is complete, an identity file is generated.

   select k1,k2,v1 from tbl1 limit 100000
   into outfile "s3a://my_bucket/export/my_file_"
   FORMAT AS CSV
   PROPERTIES
   (
       "broker.name" = "hdfs_broker",
       "broker.fs.s3a.access.key" = "xxx",
       "broker.fs.s3a.secret.key" = "xxxx",
       "broker.fs.s3a.endpoint" = "https://cos.xxxxxx.myqcloud.com/",
       "column_separator" = ",",
       "line_delimiter" = "\n",
       "max_file_size" = "1024MB",
       "success_file_name" = "SUCCESS"
   )

   If the final generated file is not larger than 1GB, it will be: my_file_0.csv. If larger than 1GB, it may be my_file_0.csv, result_1.csv, .... Verify on cos

      1. A path that does not exist will be automatically created
      2. Access.key/secret.key/endpoint needs to be confirmed with students of cos. Especially the value of endpoint does not need to fill in bucket_name.

6. Use the s3 protocol to export to bos, and enable concurrent export.

   set enable_parallel_outfile = true;
   select k1 from tb1 limit 1000
   into outfile "s3://my_bucket/export/my_file_"
   format as csv
   properties
   (
        "s3.endpoint" = "http://s3.bd.bcebos.com",
        "s3.access_key" = "xxxx",
        "s3.secret_key" = "xxx",
        "s3.region" = "bd"
   )

   The resulting file is prefixed with my_file_{fragment_instance_id}_.

7. Use the s3 protocol to export to bos, and enable concurrent export of session variables. Note: However, since the query statement has a top-level sorting node, even if the concurrently exported session variable is enabled for this query, it cannot be exported concurrently.

   set enable_parallel_outfile = true;
   select k1 from tb1 order by k1 limit 1000
   into outfile "s3://my_bucket/export/my_file_"
   format as csv
   properties
   (
        "s3.endpoint" = "http://s3.bd.bcebos.com",
        "s3.access_key" = "xxxx",
        "s3.secret_key" = "xxx",
        "s3.region" = "bd"
   )

8. Use hdfs export to export simple query results to the file hdfs://${host}:${fileSystem_port}/path/to/result.txt. Specify the export format as CSV and the user name as work. Specify the column separator as , and the row separator as \n.

   -- the default port of fileSystem_port is 9000
   SELECT * FROM tbl
   INTO OUTFILE "hdfs://${host}:${fileSystem_port}/path/to/result_"
   FORMAT AS CSV
   PROPERTIES
   (
       "fs.defaultFS" = "hdfs://ip:port",
       "hadoop.username" = "work"
   );

   If the Hadoop cluster is highly available and Kerberos authentication is enabled, you can refer to the following SQL statement:

   SELECT * FROM tbl
   INTO OUTFILE "hdfs://path/to/result_"
   FORMAT AS CSV
   PROPERTIES
   (
   'fs.defaultFS'='hdfs://hacluster/',
   'dfs.nameservices'='hacluster',
   'dfs.ha.namenodes.hacluster'='n1,n2',
   'dfs.namenode.rpc-address.hacluster.n1'='192.168.0.1:8020',
   'dfs.namenode.rpc-address.hacluster.n2'='192.168.0.2:8020',
   'dfs.client.failover.proxy.provider.hacluster'='org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider',
   'dfs.namenode.kerberos.principal'='hadoop/_HOST@REALM.COM'
   'hadoop.security.authentication'='kerberos',
   'hadoop.kerberos.principal'='doris_test@REALM.COM',
   'hadoop.kerberos.keytab'='/path/to/doris_test.keytab'
   );
   
   If the final generated file is not larger than 100MB, it will be: `result_0.csv`.
   If larger than 100MB, it may be `result_0.csv, result_1.csv, ...`.
   

9. Export the query result of the select statement to the file cosn://${bucket_name}/path/result.txt on Tencent Cloud Object Storage (COS). Specify the export format as csv. After the export is complete, an identity file is generated.

   select k1,k2,v1 from tbl1 limit 100000
   into outfile "cosn://my_bucket/export/my_file_"
   FORMAT AS CSV
   PROPERTIES
   (
       "broker.name" = "broker_name",
       "broker.fs.cosn.userinfo.secretId" = "xxx",
       "broker.fs.cosn.userinfo.secretKey" = "xxxx",
       "broker.fs.cosn.bucket.endpoint_suffix" = "cos.xxxxxx.myqcloud.com",
       "column_separator" = ",",
       "line_delimiter" = "\n",
       "max_file_size" = "1024MB",
       "success_file_name" = "SUCCESS"
   )

keywords

OUTFILE

Best Practice

1. Export data volume and export efficiency

   This function essentially executes an SQL query command. The final result is a single-threaded output. Therefore, the time-consuming of the entire export includes the time-consuming of the query itself and the time-consuming of writing the final result set. If the query is large, you need to set the session variable query_timeout to appropriately extend the query timeout.

2. Management of export files

   Doris does not manage exported files. Including the successful export, or the remaining files after the export fails, all need to be handled by the user.

3. Export to local file

   The ability to export to a local file is not available for public cloud users, only for private deployments. And the default user has full control over the cluster nodes. Doris will not check the validity of the export path filled in by the user. If the process user of Doris does not have write permission to the path, or the path does not exist, an error will be reported. At the same time, for security reasons, if a file with the same name already exists in this path, the export will also fail.

   Doris does not manage files exported locally, nor does it check disk space, etc. These files need to be managed by the user, such as cleaning and so on.

4. Results Integrity Guarantee

   This command is a synchronous command, so it is possible that the task connection is disconnected during the execution process, so that it is impossible to live the exported data whether it ends normally, or whether it is complete. At this point, you can use the success_file_name parameter to request that a successful file identifier be generated in the directory after the task is successful. Users can use this file to determine whether the export ends normally.

5. Other Points to Note

   See Export Query Result