hudiCluster Table Function

This is an extension to the hudi table function. Allows processing files from Apache Hudi tables in Amazon S3 in parallel with many nodes in a specified cluster. On initiator it creates a connection to all nodes in the cluster and dispatches each file dynamically. On the worker node it asks the initiator about the next task to process and processes it. This is repeated until all tasks are finished.

Syntax

hudiCluster(cluster_name, url [,aws_access_key_id, aws_secret_access_key] [,format] [,structure] [,compression] [,extra_credentials])

Arguments

Argument	Description
`cluster_name`	Name of a cluster that is used to build a set of addresses and connection parameters to remote and local servers.
`url`	Bucket url with the path to an existing Hudi table in S3.
`aws_access_key_id`, `aws_secret_access_key`	Long-term credentials for the AWS account user. You can use these to authenticate your requests. These parameters are optional. If credentials are not specified, they are used from the ClickHouse configuration. For more information see Using S3 for Data Storage.
`format`	The format of the file.
`structure`	Structure of the table. Format `'column1_name column1_type, column2_name column2_type, ...'`.
`compression`	Parameter is optional. Supported values: `none`, `gzip/gz`, `deflate`, `brotli/br`, `xz/LZMA`, `zstd/zst`, `lz4`, `bz2`, `snappy`. By default, compression will be autodetected by the file extension. For `snappy`, the wire format is selected by the snappy_mode setting (`basic` by default).
`extra_credentials`	Parameter is optional. Used to pass a `role_arn` for role-based access in ClickHouse Cloud. See Secure S3 for configuration steps.

Returned value

A table with the specified structure for reading data from cluster in the specified Hudi table in S3.

Virtual Columns

_path — Path to the file. Type: LowCardinality(String).
_file — Name of the file. Type: LowCardinality(String).
_size — Size of the file in bytes. Type: Nullable(UInt64). If the file size is unknown, the value is NULL.
_time — Last modified time of the file. Type: Nullable(DateTime). If the time is unknown, the value is NULL.
_etag — The etag of the file. Type: LowCardinality(String). If the etag is unknown, the value is NULL.

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