CREATE EXTERNAL TABLE|V4.3.5| docs|Distributed Database

CREATE EXTERNAL TABLE

Last Updated：2026-02-03 08:48:37 Updated

Purpose

This statement is used to create a new external table in the database.

External tables are a key feature of database management systems. Typically, tables in a database are stored in the database's storage space, while the data of external tables is stored in external storage services.

When creating an external table, you need to define the file path and file format of the data. After that, users can read data from the external storage service through the external table. External tables are read-only and can be used in query statements, but DML operations cannot be performed on them. External tables do not support defining constraints or creating indexes.

Syntax

CREATE EXTERNAL TABLE table_name (column_definition_list)
    LOCATION = 'file_name'
    {FORMAT = (format_type_options)
     | PROPERTIES = (properties_type_options)}
    [PARTITION BY (column_name [, column_name ...])]
    [PARTITION_TYPE = USER_SPECIFIED]
    [PATTERN = 'regex_pattern']
    [AUTO_REFRESH = 'xxx'];

column_definition_list:
    column_definition [, column_definition ...]

column_definition:
    column_name column_type [AS expr]

format_type_options:
    type_csv_option
    | type_parquet_option
    | type_orc_option

type_csv_option:
    TYPE = 'CSV'
    LINE_DELIMITER = '<string>' | <expr>
    FIELD_DELIMITER = '<string>' | <expr>
    ESCAPE = '<character>' | <expr>
    FIELD_OPTIONALLY_ENCLOSED_BY = '<character>' | <expr>
    ENCODING = 'charset'
    NULL_IF = ('<string>' | <expr>, '<string>' | <expr> ...)
    SKIP_HEADER = <int>
    SKIP_BLANK_LINES = {TRUE | FALSE}
    TRIM_SPACE = {TRUE | FALSE}
    EMPTY_FIELD_AS_NULL = {TRUE | FALSE}
    IGNORE_LAST_EMPTY_COLUMN = {TRUE | FALSE}

type_parquet_option:
    TYPE = 'PARQUET'

type_orc_option:
    TYPE = 'ORC'

properties_type_options:
    type_odps_option

type_odps_option:
    TYPE = 'ODPS'
    ACCESSID = '<string>'
    ACCESSKEY = '<string>'
    ENDPOINT = '<string>',
    PROJECT_NAME = '<string>',
    SCHEMA_NAME = '<string>',
    TABLE_NAME = '<string>',
    QUOTA_NAME = '<string>',
    COMPRESSION_CODE = '<string>',
    API_MODE = {"tunnel_api" | "storage_api"},
    SPLIT = {"byte" | "row"}

Parameters

Parameter	Description
table_name	The name of the external table to be created.
column_name	The name of the column in the external table. By default, the data columns in the file are automatically mapped to the columns defined in the external table in sequence.
column_type	The type of the column in the external table. Constraints such as `DEFAULT`, `NOT NULL`, `UNIQUE`, `CHECK`, `PRIMARY KEY`, and `FOREIGN KEY` cannot be defined.
AS expr	Used to manually specify column mappings. When the order of columns in the file does not match the order of columns defined in the external table, you can use the pseudo column `metadata$filecol{N}` to specify the mapping between the external table column and the Nth column in the file. For example, `c2 INT AS (metadata$filecol4)` indicates that the `c2` column in the external table corresponds to the 4th column in the file. Note that if manual column mappings are specified, automatic mappings will be disabled, and all columns must be manually mapped.
LOCATION = 'file_name'	Specifies the path where the external table file is stored. Typically, the data files of the external table are stored in a dedicated directory, which may contain subdirectories. When creating the table, the external table will automatically collect all files in this directory. For more information, see file_name below.
FORMAT = (format_type_options)	Specifies the properties of the external file format. Use `TYPE` to specify the export format as `CSV`, `PARQUET`, or `ORC`. The `TYPE` parameter is required. For more information, see format_type_options below.
PROPERTIES = (properties_type_options)	Specifies the properties of the external file format. Use `TYPE` to specify the export format as `ODPS`. The `TYPE` parameter is required. For more information, see properties_type_options below.
PATTERN	Specifies a regular expression pattern to filter files in the `LOCATION` directory. For each file path in the `LOCATION` directory, if it matches the pattern, the external table will access the file; otherwise, it will skip the file. If this parameter is not specified, all files in the `LOCATION` directory are accessible by default. The external table will save the list of files in the path specified by `LOCATION` that match the `PATTERN` in the database system table. When scanning the external table, it will access the external files based on this list.
PARTITION_TYPE = USER_SPECIFIED	Specifies `PARTITION_TYPE = USER_SPECIFIED` if you want to manually add and delete partitions instead of letting the external table automatically manage partitions.
AUTO_REFRESH = 'xxx'	Specifies whether to enable automatic refresh for the external table. Valid values: `OFF`: Default value, indicating that automatic refresh is disabled. `INTERVAL`: Specifies that the external table can be managed for automatic refresh rules using `dbms_external_table`. `IMMEDIATE`: Indicates that the external table metadata related to each SQL query must be refreshed every time the SQL query is executed.

file_name

The file path of an external table is in the following formats:

If the file is stored locally, the LOCATION parameter is in the LOCATION = '[file://] local_file_path' format, where local_file_path can be a relative or absolute path. If a relative path is specified, the current directory must be the installation directory of OceanBase Database. The secure_file_priv parameter specifies the file path that an OBServer node can access. local_file_path can only be a subpath of the secure_file_priv path.
If the file is stored remotely, the LOCATION parameter is in the following formats:

Notice

When you use an object storage path, the parameters of the object storage path are separated by the & symbol. Make sure that the parameter values you enter contain only uppercase and lowercase letters, digits, /-_$+=, and wildcards. Otherwise, the settings may fail.
- If the file is stored on Alibaba Cloud OSS or AWS S3, the LOCATION parameter is in the LOCATION = '{oss\|s3}://$ACCESS_ID:$ACCESS_KEY@$HOST:s3_region/remote_file_path' format, where $ACCESS_ID, $ACCESS_KEY, and $HOST are the access information required to access Alibaba Cloud OSS, AWS S3, and object storage services compatible with the S3 protocol, and s3_region is the region information selected when you use S3. These sensitive access parameters are stored in the system tables of the database in an encrypted manner.
- If the file is stored on HDFS, the LOCATION parameter is in the following formats:
  - If you access the cluster based on the address of a single-node NameNode (NN), the LOCATION parameter is in the LOCATION = hdfs://localhost:port/PATH format, where localhost specifies the address of HDFS, port specifies the port number of HDFS, and PATH specifies the file path in HDFS.
    - If Kerberos authentication is used, the LOCATION parameter is in the LOCATION = 'hdfs://localhost:port/user?principal=xxx&keytab=xxx&krb5conf=xxx&configs=xxx' format, where:
      - principal: specifies the user for login authentication.
      - keytab: specifies the path of the key file for user authentication.
      - krb5conf: specifies the path of the description file for the Kerberos environment.
      - configs: specifies additional HDFS configuration items. By default, this parameter is empty. However, in a Kerberos environment, this parameter usually has a value and needs to be configured. For example, dfs.data.transfer.protection=authentication,privacy specifies the data transfer protection level as authentication and privacy.
  - If you access the cluster based on the Hadoop high availability (HA) logical naming service, the LOCATION parameter is in the LOCATION = hdfs://nameserviceID/PATH format, where nameserviceID specifies the ID of the Hadoop HA logical naming service of HDFS, and PATH specifies the file path.
    
    Note
    
    Make sure that the client side of the OBServer node contains the nameservice definition and failover strategy of the HA cluster.
    - If Kerberos authentication is used, the LOCATION parameter is in the LOCATION = 'hdfs://nameserviceID/PATH?principal=xxx&keytab=xxx&krb5conf=xxx&configs=dfs.data.transfer.protection=${string}#dfs.nameservices=${nameservice id}#dfs.ha.namenodes.${nameservice id}=${namenode1}, ${namenode2}#dfs.namenode.rpc-address.${nameservice id}.${namenode1}=${namenode 1 address}#dfs.namenode.rpc-address.${nameservice id}.${namenode2}=${namenode 2 address}#dfs.ha.automatic-failover.enabled.${nameservice id}=true#dfs.client.failover.proxy.provider.${nameservice id}=org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider' format, where:
      - principal: specifies the user for login authentication. Set this parameter to the pricipal of a non-primary NN.
      - keytab and krb5conf: are the same as those in the single-node NN configuration.
      - configs: specifies additional HDFS configuration items. If multiple configuration items are set, they are related to HA and security configurations:
        
        dfs.data.transfer.protection=${string}: specifies the dfs.data.transfer.protection parameter of the cluster.
        
        dfs.nameservices=${nameservice id}: specifies the namesevice (alias) of the current HA cluster.
        
        dfs.ha.namenodes.${nameservice id}=${namenode1}, ${namenode2}: specifies the list of namenode IDs in the HA cluster.
        
        dfs.namenode.rpc-address.${nameservice id}.${namenode1}=${namenode 1 address}: specifies the specific namenode for namenode1 to facilitate client routing.
        
        dfs.namenode.rpc-address.${nameservice id}.${namenode2}=${namenode 2 address}: specifies the specific namenode for namenode2 to facilitate client routing.
        
        dfs.ha.automatic-failover.enabled.${nameservice id}=true: allows the HA cluster to automatically obtain a valid namenode to respond to requests after receiving them.
        
        dfs.client.failover.proxy.provider.${nameservice id}=org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider: specifies the logical tool class for switching between primary and standby nodes in the HA cluster. You can also customize and upload the logic required by the HA cluster.
    Notice
    
    Some HA configuration items are bound to the namespace. For example, in the following sample three, the mycluster is the namespace. Make sure to set the related configuration items accordingly.

format_type_options

TYPE = 'CSV': specifies the external file format as CSV. It also includes the following fields:
- LINE_DELIMITER: specifies the line delimiter for the CSV file. The default value is LINE_DELIMITER='\n'.
- FIELD_DELIMITER: specifies the column delimiter for the CSV file. The default value is FIELD_DELIMITER='\t'.
- ESCAPE: specifies the escape character for the CSV file, which must be a single byte. The default value is ESCAPE ='\'.
- FIELD_OPTIONALLY_ENCLOSED_BY: specifies the character used to enclose field values in the CSV file. The default value is empty.
  
  Notice
  
  When the external table data file contains NULL values (non-string NULL, i.e., not "NULL"), you must explicitly configure the FIELD_OPTIONALLY_ENCLOSED_BY parameter, and the value of this parameter cannot be empty.
- ENCODING: specifies the character set encoding format of the file. For information about all character sets supported in MySQL mode, see Character sets. If not specified, the default value is UTF8MB4.
- NULL_IF: specifies the string to be treated as NULL. The default value is empty.
- SKIP_HEADER: skips the header and specifies the number of rows to skip.
- SKIP_BLANK_LINES: specifies whether to skip blank lines. The default value is FALSE, indicating that blank lines are not skipped.
- TRIM_SPACE: specifies whether to remove leading and trailing spaces from fields in the file. The default value is FALSE, indicating that leading and trailing spaces are not removed.
- EMPTY_FIELD_AS_NULL: specifies whether to treat empty strings as NULL. The default value is FALSE, indicating that empty strings are not treated as NULL.
- IGNORE_LAST_EMPTY_COLUMN: specifies whether to ignore the last empty field at the end of a line in the file. The default value is TRUE, indicating that the last empty field is ignored.
  
  Note
  
  For OceanBase Database V4.3.5, the IGNORE_LAST_EMPTY_COLUMN parameter is supported starting from V4.3.5 BP2.
TYPE = 'PARQUET': specifies the external file format as PARQUET.
TYPE = 'ORC': specifies the external file format as ORC.

properties_type_options

TYPE = 'ODPS': specifies the external file format as ODPS. It also includes the following fields:
- ACCESSID: specifies the AccessKey ID of the Alibaba Cloud account for identity authentication.
- ACCESSKEY: specifies the AccessKey Secret corresponding to the AccessKey ID for authentication.
- ENDPOINT: specifies the endpoint of the ODPS service.
- PROJECT_NAME: specifies the name of the target ODPS project.
- SCHEMA_NAME: specifies the name of the schema in ODPS. This parameter is optional.
- TABLE_NAME: specifies the name of the target table in ODPS.
- QUOTA_NAME: specifies the quota to use. This parameter is optional.
- COMPRESSION_CODE: specifies the compression format of the data source. Valid values: ZLIB, ZSTD, LZ4, and ODPS_LZ4. If this parameter is not specified, compression is not enabled.
- API_MODE: specifies the API mode for calling ODPS. Valid values:
  
  Note
  
  For OceanBase Database V4.3.5, the API_MODE and SPLIT parameters are supported starting from V4.3.5 BP3.
  - tunnel_api (default):
    - No special network configuration is required: applicable to all deployment scenarios, without the need for OceanBase Database and MaxCompute to be in the same VPC (Virtual Private Cloud).
    - No additional MaxCompute permissions are required: only the AccessID and AccessKey are needed for authentication, without the need to enable the MaxCompute Storage API permission.
    - Applicable environments:
      - OceanBase Database and MaxCompute are not deployed in the same VPC.
      - The MaxCompute Storage API is not enabled.
      - Data transmission has low latency requirements.
  - storage_api:
    - Network dependency: requires OceanBase Database and MaxCompute to be deployed in the same VPC to achieve low-latency, high-throughput data transmission.
    - Permission dependency: requires the Storage API permission to be enabled in MaxCompute and ensures that the AccessKey has the necessary permissions.
    - Applicable environments:
      - OceanBase Database and MaxCompute are in the same VPC.
      - The MaxCompute Storage API is enabled.
      - The data volume is extremely large or the real-time requirement is high.
- SPLIT: specifies the unit for task splitting when using storage_api. Valid values: byte and row. If the data size of each row in a table varies significantly, set SPLIT to byte. Otherwise, set it to row.

Considerations

When an external file is deleted, the external table ignores the file if it no longer exists in the file list.
When an external file is modified, the external table accesses the latest data in the file. If the external file is modified concurrently with an external table query, unexpected results may occur. To avoid this, do not modify the external file during a query.
When a new file is added to the external directory, the external table only accesses files listed in the file list. To include the new file in the external table's file list, you need to update the external table's file list.

Examples

Example 1

Prepare the data. First, set the secure_file_priv path to /home/admin/ and place the CSV file extdata.csv corresponding to the external table data in the /home/admin/test directory of the current OBServer node.

Here is an example of setting the global secure file path.
```
obclient> SET GLOBAL secure_file_priv = "/home/admin/";
Query OK, 0 rows affected
obclinet> \q
Bye
```
Note

Since secure_file_priv is a GLOBAL variable, you need to execute \q to exit and make the setting take effect.

The content of the CSV file is as follows:
```
1,'Dave','Smith','dsmith@outlook.com','friend',32
2,'Xena','Johnson','xjonson@outlook.com','contact',45
3,'Fred','Jackon','fjackson@outlook.com','co-worker',19
4,'Alma','Tyler','atyler@outlook.com','friend',53
```

After logging in to the database as a user in a user tenant, create the external table contacts.

obclient> CREATE EXTERNAL TABLE contacts (
    id    INT,
    firstname  VARCHAR(100),
    lastname   VARCHAR(100),
    email      VARCHAR(255),
    category   CHAR(30),
    age        NUMBER
   )
   LOCATION = '/home/admin/test'
   FORMAT = (
     TYPE = 'CSV'
     FIELD_DELIMITER = ','
     FIELD_OPTIONALLY_ENCLOSED_BY ='\''
    )
  PATTERN = 'extdata.csv';

Query the data in the external table contacts.

obclient> SELECT * FROM contacts;
+----+-----------+----------+----------------------+-----------+------+
| id | firstname | lastname | email                | category  | age  |
+----+-----------+----------+----------------------+-----------+------+
|  1 | Dave      | Smith    | dsmith@outlook.com   | friend    |   32 |
|  2 | Xena      | Johnson  | xjonson@outlook.com  | contact   |   45 |
|  3 | Fred      | Jackon   | fjackson@outlook.com | co-worker |   19 |
|  4 | Alma      | Tyler    | atyler@outlook.com   | friend    |   53 |
+----+-----------+----------+----------------------+-----------+------+
4 rows in set

Example 2

Assume that there is a CSV file in a certain file path on HDFS, and the content of the file is as follows:

$hdfs dfs -cat /user/test_tbl1.csv
1,'Emma','2021-09-01'
2,'William','2021-09-02'
3,'Olivia','2021-09-03'

Create an HDFS external table.

If Kerberos authentication is not enabled in the target HDFS environment:
```
CREATE EXTERNAL TABLE test_tbl1_csv_mysql (
  id INT,
  name VARCHAR(50),
  c_date    DATE
)
LOCATION = 'hdfs://${hadoop namenode hostname}:${hadoop namenode port}/user'
FORMAT = (
TYPE = 'CSV'
FIELD_DELIMITER = ','
FIELD_OPTIONALLY_ENCLOSED_BY ='\''
)
PATTERN = 'test_tbl1.csv';
```
Notice

Here, hadoop namenode hostname and hadoop namenode port refer to the host name and port of the HDFS node, which need to be replaced with the actual values.

If Kerberos authentication is enabled in the target HDFS environment:
1. Prepare the environment. Since the current HDFS integration uses the JNI framework, the corresponding environment must support the deployment of a Java environment. If OBServer is deployed across multiple nodes, the corresponding OBServer nodes must also be configured with the following environment settings, not just a single node.
  
  Step 1: Deploy and configure the Java environment
  
  You can download the latest version of OpenJDK 8 from openjdk.
  
  Step 2: Decompress the installation package
  
  After decompressing, you will see the following files:
```
$ ls $JAVA_HOME
ASSEMBLY_EXCEPTION  bin  include  jre  lib  LICENSE  man  NOTICE  release  sample  src.zip  THIRD_PARTY_README
```
  Step 3: Deploy and configure the HDFS.so dynamic library
  
  You can download the required dependencies from https://mirrors.aliyun.com/oceanbase/. After downloading, install it using the following command:
```
sudo rpm -Uvh
devdeps-hdfs-sdk-3.3.6-xxxxx.xxx.xxx.rpm
```
  Run the following command to check if the installation meets your expectations. You should have both libhdfs.so and libhdfs.so.0.0.0 files, and the corresponding symbolic links should be valid.
```
$ll /usr/local/oceanbase/deps/devel/lib
total 376
lrwxrwxrwx 1 root root     16 Dec 24 19:49 libhdfs.so -> libhdfs.so.0.0.0
-rwxr-xr-x 1 root root 384632 Dec 24 19:09 libhdfs.so.0.0.0
```
  Step 4: Deploy and configure the jar package path
  
  After downloading the required jar package, you can execute the following command to decompress and install it:
```
sudo rpm -Uvh
devdeps-java-extensions-3.3.6--xxxxx.xxx.xxx.rpm
```
  Check if the installation meets your expectations:
```
$ll /home/admin/oceanbase/jni_packages
total 52756
drwxr-sr-x 4 root root     4096 Dec 24 20:25 hadoop
drwxr-xr-x 3 root root     4096 Dec 24 20:25 lib
-rw-r--r-- 1 root root 54008720 Dec 24 19:52 oceanbase-odps-connector-jar-with-dependencies.jar
```
  Step 4: Deploy and configure the jar package path:
  1. Download the jar package: Visit OceanBase Database Mirror to download the jar package.
    Notice
    - For OceanBase Database V4.3.5 BP1 and earlier versions: Please download the 1.0.0 version of the devdeps-java-extensions RPM installation package.
    - For OceanBase Database V4.3.5 BP2 and later versions: Please download the 1.0.1 version of the devdeps-java-extensions RPM installation package.
    - For OceanBase Database V4.4.0: Please download the 1.0.1 version of the devdeps-java-extensions RPM installation package.
  2. Install the jar package: After downloading the required jar package, execute the following command to decompress and install it:
```
sudo rpm -Uvh devdeps-java-extensions-x.x.x-xxxxxxxxxxxx.xxx.xxxxxx.rpm
```
  3. Check if the installation meets your expectations:
```
$ll /home/admin/oceanbase/jni_packages
total 52756
drwxr-sr-x 4 root root     4096 Dec 24 20:25 hadoop
drwxr-xr-x 3 root root     4096 Dec 24 20:25 lib
-rw-r--r-- 1 root root 54008720 Dec 24 19:52 oceanbase-odps-connector-jar-with-dependencies.jar
```
2. Start the OBSERVER
  
  Before using the HDFS external table, you need to configure the corresponding OBServer node. The configuration is as follows:
  
  Note
  
  Due to the limitations of the current OBServer's JNI-related configuration items, which cannot be flexibly set and take effect immediately, any changes to the Java environment variables require a restart of the OBServer. All the following configurations are cluster-level settings, so they only need to be set once, without needing to configure each node individually.
  - Execute the following command as the sys tenant to enable the Java environment supported by OBServer:
```
alter system set ob_enable_java_env=true;
```
  - Execute the following command to set the Java home path for OBServer:
```
alter system set ob_java_home="/home/user/openjdk/jdk8u422-b05";
```
    Note
    
    The path comes from the installation path of the Open JDK Java.
  - Set the relevant configuration items for Java environment startup:
    
    Notice
    
    Changes to this configuration item will take effect after a restart of the OBServer. Since the current HDFS integration uses direct memory copy from the HDFS data stream to the C++ memory heap, you can appropriately reduce the settings for -Xmx2048m and -Xms2048m.
```
alter system set ob_java_opts="-Djdk.lang.processReaperUseDefaultStackSize=true -XX:+HeapDumpOnOutOfMemoryError -Xmx2048m -Xms2048m -Xloggc:/home/user/jvmlogs/gc.log -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/home/user/jvmlogs/heapdumps/  -XX:+UseG1GC  -XX:-CriticalJNINatives";
```
    Note
    
    Here, /home/user/jvmlogs and /home/user/jvmlogs/heapdumps are the paths for generating the corresponding log folders, which need to be manually created.
  - Set the available LD_LIBRARY_PATH path:
    
    Note
    
    Since the JNI SDK supported by OBServer is an extended feature, it uses dynamic library loading. Therefore, you need to configure the corresponding dynamic library path by setting LD_LIBRARY_PATH. All OBServer nodes must be configured to use this feature.
```
$ vim ~/.bashrc
export LD_LIBRARY_PATH=/home/user/openjdk/jdk8u422-b05/jre/lib/amd64/server:/usr/local/oceanbase/deps/devel/lib
```
3. Create the HDFS external table.
  
  Notice
  
  If Kerberos authentication is configured, the corresponding OBServer node must deploy and configure the keytab (user authentication key file) and krb5conf file.
```
CREATE EXTERNAL TABLE partsupp  ( PS_PARTKEY     INTEGER ,
PS_SUPPKEY     INTEGER ,
PS_AVAILQTY    INTEGER ,
PS_SUPPLYCOST  DECIMAL(15,2)  ,
PS_COMMENT     VARCHAR(199)
) LOCATION = 'hdfs://localhost:8020/tpch_csv?principal=principal_str&keytab=/path/to/keytab&krb5conf=/path/to/krb5conf_file&configs=xxx=xxx#xxx=xxx'
FORMAT = (
  TYPE = 'CSV'
  FIELD_DELIMITER = '|'
  FIELD_OPTIONALLY_ENCLOSED_BY ='"'
  )
PATTERN = 'partsupp.tbl';
```

Query the external table data.

select * from test_tbl1_csv_mysql;

The returned result is as follows:

+----+----------+------------+
| id | name     | c_date     |
+----+----------+------------+
|  1 | Emma     | 2021-09-01 |
|  2 | William  | 2021-09-02 |
|  3 | Olivia   | 2021-09-03 |
+----+----------+------------+
3 rows in set

Example 3

Assume that a CSV file is stored in a specified directory on HDFS. The content of the file is as follows:
```
$hdfs dfs -cat /hadoop_ha_test/test_simple.csv
1,lili,19
2,alic,20
3,solvi,21
```
Start the Observer-related JNI configuration items.

For more information about the JNI configuration, see the Environment preparation section in Step 2 under If Kerberos authentication is enabled in the target HDFS environment. For more information, see Deploy the OceanBase Database Java SDK environment.

Create an HDFS external table.

obclient> CREATE EXTERNAL TABLE test_ha (
    id INT,
    r_name VARCHAR(100),
    age INT
    )
    LOCATION = 'hdfs://mycluster/hadoop_ha_test?principal=ha/xxx@xxx.com&keytab=/path/to/ha.keytab&krb5conf=/path/to/krb5conf_file&configs=dfs.data.transfer.protection=integrity#dfs.nameservices=mycluster#dfs.ha.namenodes.mycluster=nn1,nn2#dfs.namenode.rpc-address.mycluster.nn1=localhost1:port#dfs.namenode.rpc-address.mycluster.nn2=localhost2:port#dfs.ha.automatic-failover.enabled.mycluster=true#dfs.client.failover.proxy.provider.mycluster=org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider'
    FORMAT = (
        TYPE = 'CSV'
        FIELD_DELIMITER = ','
        FIELD_OPTIONALLY_ENCLOSED_BY = '\''
        )
    PATTERN = 'test_simple.csv';

Query data from the external table.

obclient> SELECT * FROM test_ha;

The returned result is as follows:

+----+--------+-------+
| id | r_name | age   |
+----+--------+-------+
|  1 | lili   |    19 |
|  2 | alic   |    20 |
|  3 | solvi  |    21 |
+----+--------+-------+
3 rows in set

CREATE EXTERNAL TABLE

Purpose

Syntax

Parameters

file_name

Notice

Note

Notice

format_type_options

Notice

Note

properties_type_options

Note

Considerations

Examples

Example 1

Note

Example 2

Notice

Notice

Note

Note

Notice

Note

Note

Notice

Example 3

References