VeloDB Cloud
SQL Manual
Statments
Data-Manipulation-Statements
OUTFILE

OUTFILE

Name

OURFILE

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, the S3 protocol, or the HDFS protocol.

Syntax:

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

Note:

  1. file_path

    file_path 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

  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.

  3. properties

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

    grammar:
[PROPERTIES ("key"="value", ...)]
The following properties are supported:
column_separator: column separator. <version since="1.2.0">Support mulit-bytes, such as: "\\x01", "abc"</version>
line_delimiter: line delimiter. <version since="1.2.0">Support mulit-bytes, such as: "\\x01", "abc"</version>
max_file_size: the size limit of a single file, if the result exceeds this value, it will be cut into multiple files.

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:
AWS_ENDPOINT
AWS_ACCESS_KEY
AWS_SECRET_KEY
AWS_REGION

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",
    "schema"="required,int32,c1;required,byte_array,c2;required,byte_array,c2"
);

    Exporting query results to parquet files requires explicit schema.

  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",
    "schema"="required,int32,k1;required,byte_array,k2"
);

  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
(
    "AWS_ENDPOINT" = "http://s3.bd.bcebos.com",
    "AWS_ACCESS_KEY" = "xxxx",
    "AWS_SECRET_KEY" = "xxx",
    "AWS_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
(
    "AWS_ENDPOINT" = "http://s3.bd.bcebos.com",
    "AWS_ACCESS_KEY" = "xxxx",
    "AWS_SECRET_KEY" = "xxx",
    "AWS_REGION" = "bd"
)

  8. Use hdfs export to export simple query results to the file hdfs://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.

    SELECT * FROM tbl
INTO OUTFILE "hdfs://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" = "https://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.

TRUNCATE-TABLEALTER-ROUTINE-LOAD
© VeloDB Inc. ｜ Apache, Doris, Apache Doris, the Apache feather logo and the Apache Doris logo are trademarks of The Apache Software Foundation.