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Brendan Clement
06aa526ae1
This PR is part of the documentation revamp. Once the full set of PRs is merged, we’ll publish the combined site to staging for review before updating docs.lancedb.com. The curation, SQL and operations pages contain outdated claims and examples that do not reliably work as written. This corrects those pages against the reviewed SDK and local server evidence, including prepared statements, background jobs, cleanup and monitoring. Integration guides are grouped with their examples in #4533. Function and Secret-object documentation stays unpublished until its release. The two Function pages are listed in `.mintignore` and left out of the navigation, and the sections about them on other pages are MDX comments. Stacked on #4533. Each MDX file has one PR owner. Rebase onto main after #4533 is squash-merged. Local assembly, Mint validation and link checks pass, and the assembled site shows no Function or Secret-object content. A local release rehearsal that uncomments the drafts and restores the navigation also passes. Hold publication until this PR and lancedb/sophon#8688 are on `main`.
92 lines
3.1 KiB
Plaintext
92 lines
3.1 KiB
Plaintext
---
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title: "Function"
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sidebarTitle: "Function"
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description: "CREATE FUNCTION, SHOW FUNCTIONS, and DROP FUNCTION."
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icon: function
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keywords: ["create function", "drop function", "show functions", "sql", "udf"]
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---
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<Badge color="red">Enterprise</Badge> [SQL runs in LanceDB Enterprise.](/sql)
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## CREATE FUNCTION {#create}
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```sql
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CREATE FUNCTION f(x int64) RETURNS int64
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LANGUAGE python
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AS 'def f(x): return x * 2'
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WITH (pip = 'numpy==1.26.4', python_version = '3.11')
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```
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Parameter and result types are Arrow type names, not SQL ones: `int64`,
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`float64`, `utf8`, `bool`, `date32`, and lists such as `list<float32>` or
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`fixed_size_list<float32, 768>`. `BIGINT` is refused. A parameter accepts nulls
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unless it is declared `NOT NULL`.
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The body is Python source. Its dependencies are declared with it and are part
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of the **immutable function version** -- changing one produces a new version
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rather than altering the registered one, so a column filled by an earlier
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version is unaffected.
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| Option | |
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| --- | --- |
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| `pip` | pip requirements for the worker environment |
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| `conda` | conda packages instead of pip |
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| `conda_channels` | channels in priority order; requires `conda` |
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| `python_version` | worker Python version; `3.12` when omitted, whatever Python you send the statement from |
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| `gpu` | `'true'` when every execution needs a GPU |
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**Errors and limits**
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| | |
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| --- | --- |
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| `LANGUAGE` other than `python` | refused |
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| `pip` and `conda` together | refused -- pick one |
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| `conda_channels` without `conda` | refused |
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| `gpu` set to anything but `'true'` | refused |
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| An empty body | refused |
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| Any other option | refused, and the message lists what is supported |
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<Note>
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**Enterprise job type:** `create_function`. Registration returns a job because
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the function is baked into an image before the version becomes usable.
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</Note>
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## SHOW FUNCTIONS {#show}
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```sql
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SHOW FUNCTIONS
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```
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Lists registered functions and their versions. Since a version is immutable
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and a column pins the version that fills it, this is how you find which
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versions are still in use before dropping one.
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## DROP FUNCTION {#drop}
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```sql
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DROP FUNCTION embed WITH (version = '1')
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DROP FUNCTION IF EXISTS embed WITH (version = '1')
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DROP FUNCTION embed WITH (version = '1', cascade = 'true')
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```
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`version` is required -- a function is a set of immutable versions, and
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dropping is always of one specific version, never "the function" as a whole.
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<Warning>
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Without `cascade = 'true'`, dropping a version that a column still pins fails
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rather than breaking that column silently. Passing it drops the version and
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lets columns pinned to it stop refreshing -- they keep their last-filled
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values, per [Guarantees](/basics/guarantees#jobs).
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</Warning>
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## What to read next {#next}
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<CardGroup cols={2}>
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<Card title="Function" icon="function" href="/management/function">
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Registering one from the SDK, and diagnosing environment mismatches.
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</Card>
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<Card title="Computed columns" icon="table-columns" href="/feature-engineering/add-computed-column">
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Filling a column with a function instead of an expression.
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</Card>
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</CardGroup>
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