File Naming with Text Output (CSV, JSON, or XML)

Describes the file naming and output files for DBMS_CLOUD.EXPORT_DATA results with CSV, JSON, or XML output.

DBMS_CLOUD.EXPORT_DATA performs the query specified with the query parameter and sends the results to text files on Object Store (either CSV, JSON, or XML depending on the format type parameter). To speed up the procedure and to generate the output as fast as possible, DBMS_CLOUD.EXPORT_DATA divides its work. This means that, depending on system resources, when you run DBMS_CLOUD.EXPORT_DATA the procedure creates multiple output files in the Cloud Object Store bucket.

The format for each generated file is:

[FileNamePrefix | client_info_module_action]_sequenceNum_timestamp.format_extension.[compression_extension]

• FileNamePrefix: (optional) If a FileNamePrefix is supplied, DBMS_CLOUD.EXPORT_DATA uses the file name prefix to generate file names for the results. The FileNamePrefix is specified using the text supplied after the bucket name in the file_uri_list parameter value.

  You cannot provide multiple values for the FileNamePrefix in the file_uri_list.

• client_info_module_action: If a file name prefix is not supplied with the file_uri_list parameter, DBMS_CLOUD.EXPORT_DATA uses the combination of client_info, application module and action as the file name prefix (when this information is available). The procedure obtains these names from the application information for the database session that runs the query. See DBMS_APPLICATION_INFO for information on client_info, module name, and action name.

  If a file name prefix is not supplied with the file_uri_list and the database session attributes are not available, DBMS_CLOUD.EXPORT_DATA uses the file name prefix "data".

• sequenceNum: The sequence number associated with the DBMS_CLOUD.EXPORT_DATA query. Depending on the query, the database service, and the number of OCPUs in the Autonomous Database instance, there are one or more sequenceNums. Also, depending on the size of the results, there are one or more output files for each sequenceNum.

  See Manage Concurrency and Priorities on Autonomous Database for information on database services.

• timestamp: Timestamp when the file is uploaded.

• format_extension: The default value depends on the format type value:

  • CSV format: .csv
  • JSON format: .json
  • XML format: .xml

  For more information, see the description for format option fileextension in DBMS_CLOUD Package Format Options for EXPORT_DATA with Text Files (CSV, JSON, and XML).

• compression_extension: When you include the format parameter with the compression option with the value gzip, this is "gz".

For example, the file name prefix in the following DBMS_CLOUD.EXPORT_DATA procedure is specified in the file_url_list parameter, as dept_export.

BEGIN
  DBMS_CLOUD.EXPORT_DATA(
    credential_name => 'DEF_CRED_NAME',
    file_uri_list   => 'https://objectstorage.us-phoenix-1.oraclecloud.com/n/namespace-string/b/bucketname/o/dept_export',
    query           => 'SELECT * FROM DEPT',
    format          => JSON_OBJECT('type' value 'json'));
END;
/

When you specify a file name prefix the generated output files include the file name prefix, similar to the following:

dept_export_1_20210809T173033Z.json
dept_export_2_20210809T173034Z.json
dept_export_3_20210809T173041Z.json
dept_export_4_20210809T173035Z.json

The number of generated output files depends on the size of the results, the database service, and the number of OCPUs in the Autonomous Database instance.

In the following example the file_url_list parameter does not include a file name prefix and the compression parameter is supplied, with value gzip:

BEGIN
  DBMS_CLOUD.EXPORT_DATA(
    credential_name => 'DEF_CRED_NAME',
    file_uri_list   => 'https://objectstorage.us-phoenix-1.oraclecloud.com/n/namespace-string/b/bucketname/o/',
    query           => 'SELECT * FROM DEPT',
    format          => json_object('type' value 'json', 'compression' value 'gzip'));
END;
/

When a file name prefix is not in the file_uri_list parameter, DBMS_CLOUD.EXPORT_DATA uses a file name prefix of the form: client_info_module_action. For this example the generated output files include the file name prefix that DBMS_CLOUD.EXPORT_DATA supplies and the files are compressed with gzip and the file extension .gz is added, as follows:

Client1_Module1_Action1_1_20210809T173033Z.json.gz
Client1_Module1_Action1_2_20210809T173034Z.json.gz
Client1_Module1_Action1_3_20210809T173041Z.json.gz
Client1_Module1_Action1_4_20210809T173035Z.json.gz

If the client_info_module_action session information is not available when you run DBMS_CLOUD.EXPORT_DATA, the file name prefix is set to data. For example:

data_1_20210809T173033Z.json.gz
data_2_20210809T173034Z.json.gz
data_3_20210809T173041Z.json.gz
data_4_20210809T173035Z.json.gz

Notes for file naming with DBMS_CLOUD.EXPORT_DATA:

• DBMS_CLOUD.EXPORT_DATA does not create buckets.

• The number of files that DBMS_CLOUD.EXPORT_DATA generates is determined by the number of OCPUs, the database service, and the size of the result data.

• When a generated file contains 10MB of data, a new output file is created. However, if you have less than 10MB of result data you may have multiple output files, depending on the database service and the number of OCPUs for the Autonomous Database instance.

• The default output file chunk size is 10MB. You can change this value with the format parameter maxfilesize option. See DBMS_CLOUD Package Format Options for EXPORT_DATA with Text Files (CSV, JSON, and XML) for more information.