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    Realtime Compute for Apache Flink:FETCH_CONTENT

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    Realtime Compute for Apache Flink:FETCH_CONTENT

    Last Updated:Jun 02, 2026

    Downloads a file from a URI and returns its content as a byte array.

    Engine requirement

    The FETCH_CONTENT function requires Ververica Runtime (VVR) 11.6.0 or later.

    Syntax

    VARBINARY FETCH_CONTENT(VARCHAR uri)
VARBINARY FETCH_CONTENT(VARCHAR uri, INTEGER httpRetryCount)

    Parameters

    Parameter

    Type

    Description

    uri

    VARCHAR

    The file URI. Supported schemes include HTTP, HTTPS, and any scheme supported by the Flink FileSystem:

    • http:// or https://: An HTTP or HTTPS link.

    • oss://: An Alibaba Cloud OSS path.

    • hdfs://: An HDFS path.

    • file://: A local file path.

    httpRetryCount

    INTEGER

    Optional. Number of retries for HTTP/HTTPS requests. Default: 3. Throws an exception after all httpRetryCount retries fail.
    Note

    • Returns NULL if uri is NULL. For a non-NULL uri, a failed download throws an exception.

    • If the uri specifies an OSS path, configure access credentials as described in Configure bucket authentication.

    • If httpRetryCount is negative or NULL, the default value is used.

    Return value

    Type

    Description

    VARBINARY

    File content

    Example 1

    • Test data

      Table 1. T1

      input

      uri (VARCHAR)

      1

      http://example.com/image_url

      2

      oss://example-bucket/example.pdf

      3

      NULL

    • Test query

      SELECT 
    id,
    FETCH_CONTENT(uri) AS `value`
FROM 
    T1;

    • Test result

      id (INT)

      value (VARBINARY)

      1

      x'ffd8ffe00010......'

      2

      x'aaffd8ffe000......'

      3

      NULL

    Example 2

    • Test data

      Table 1. T2

      id (INT)

      uri (VARCHAR)

      1

      http://example.com/image_url

      2

      http://example.com/not_exist_image_url

    • Test query

      SELECT 
    id,
    FETCH_CONTENT(uri, 5) AS `value`
FROM 
    T2;

    • Test result

      id (INT)

      value (VARBINARY)

      1

      x'ffd8ffe00010......'

      If the URL does not exist, the function throws an exception after 5 retries:

      Caused by: java.io.IOException: HTTP request failed with response code: 404 for URL

    References