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Hashes a value using MurmurHash3 and assigns it to a bucket number, according to the Iceberg partition transforms specification.

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Syntax

ICEBERG_BUCKET(<value>, <num_buckets>)

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Parameters

ParameterDescriptionSupported input types
<value>The value to hash into a bucket.INTEGER, BIGINT, TEXT, BYTEA, DATE, TIMESTAMP, TIMESTAMPTZ
<num_buckets>The number of buckets. Must be a positive constant.BIGINT

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Return type

INTEGER Returns a bucket number from 0 to num_buckets - 1.

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Remarks

The ICEBERG_BUCKET function can be used in the PARTITION BY clause of CREATE ICEBERG TABLE commands. 
CREATE ICEBERG TABLE events
  PARTITION BY (iceberg_bucket(user_id, 16))
  AS SELECT * FROM source_events
WITH LOCATION = my_iceberg_location;
The bucket number is calculated by applying MurmurHash3 to the value, then taking the modulo with the number of buckets. The hash calculation follows the Iceberg 32-bit hash requirements. The <num_buckets> parameter must be a positive constant value. Using zero, negative values, or non-constant expressions results in an error.

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Example

SELECT iceberg_bucket(34, 1024) AS bucket_partition;
bucket_partition int
339

Rows: 1Execution time: 5.11ms