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<AgentInstructions>

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```json
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  "path": "/reference-sql/functions-reference/iceberg/partitioning/iceberg_bucket",
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</AgentInstructions>

> Hash value into a bucket according to Iceberg partition transforms

# ICEBERG_BUCKET

Hashes a value using MurmurHash3 and assigns it to a bucket number, according to the [Iceberg partition transforms specification](https://iceberg.apache.org/spec/#partition-transforms).

## Syntax

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
ICEBERG_BUCKET(<value>, <num_buckets>)
```

## Parameters

| Parameter       | Description                                         | Supported 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`                                                                 |

## Return type

`INTEGER`

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

## Remarks

The `ICEBERG_BUCKET` function can be used in the `PARTITION BY` clause of [`CREATE ICEBERG TABLE`](/reference-sql/commands/data-definition/create-iceberg-table-as-select) commands.

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
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](https://iceberg.apache.org/spec/#appendix-b-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.

## Example

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT iceberg_bucket(34, 1024) AS bucket_partition;
```

**Returns:**

| bucket\_partition |
| :---------------- |
| 339               |