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https://issues.apache.org/jira/browse/FLINK-39604?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-39604:
-----------------------------------
Labels: pull-request-available (was: )
> Extend DESCRIBE FUNCTION EXTENDED to support PTF fields
> -------------------------------------------------------
>
> Key: FLINK-39604
> URL: https://issues.apache.org/jira/browse/FLINK-39604
> Project: Flink
> Issue Type: Improvement
> Components: Table SQL / API
> Affects Versions: 2.2.0
> Reporter: Natea Eshetu Beshada
> Assignee: Natea Eshetu Beshada
> Priority: Minor
> Labels: pull-request-available
>
> DESCRIBE FUNCTION EXTENDED was introduced in FLINK-35822 before Process Table
> Functions (PTFs) landed under FLIP-440 (FLINK-36705 and follow-ups). As a
> result, none of the metadata that makes a PTF distinctive is shown today.
> Currently, DescribeFunctionOperation#execute emits, under the EXTENDED
> branch, only:
> - kind
> - requirements
> - is deterministic
> - supports constant folding
> - signature
> It calls FunctionDefinition#getTypeInference(...) solely to render the
> signature, ignoring the PTF-specific data already available on the same
> TypeInference instance:
> - TypeInference#getStaticArguments() — per-argument traits such as
> ROW_SEMANTIC_TABLE / SET_SEMANTIC_TABLE, OPTIONAL_PARTITION_BY,
> PASS_COLUMNS_THROUGH, SUPPORT_UPDATES, REQUIRE_UPDATE_BEFORE,
> REQUIRE_FULL_DELETE, REQUIRE_ON_TIME.
> - TypeInference#getStateTypeStrategies() — named state entries with their
> declared types and TTL (from @StateHint(ttl = ...)).
> This makes it hard for users to introspect PTFs from SQL — e.g. to confirm a
> function carries state, what its TTL is, or whether an argument requires ON
> TIME.
> Proposed Changes
> When DESCRIBE FUNCTION EXTENDED targets a function whose TypeInference
> exposes static arguments and/or state entries, append additional rows to the
> existing (info name, info value) result, e.g.:
> {{
> +-----------------------------+-----------------------------------------------+}}
> {{ | info name | info value
> |}}
> {{
> +-----------------------------+-----------------------------------------------+}}
> {{ | kind | PROCESS_TABLE
> |}}
> {{ | requirements | []
> |}}
> {{ | is deterministic | true
> |}}
> {{ | supports constant folding | false
> |}}
> {{ | signature | f(input => <ROW...>, on_time =>
> <TIMESTAMP>) |}}
> {{ | argument: input | type=ROW<...>,
> traits=[SET_SEMANTIC_TABLE, |}}
> {{ | | OPTIONAL_PARTITION_BY, SUPPORT_UPDATES]
> |}}
> {{ | argument: on_time | type=TIMESTAMP_LTZ(3),
> traits=[REQUIRE_ON_TIME]|}}
> {{ | state: counter | type=BIGINT, ttl=1 d
> |}}
> {{
> +-----------------------------+-----------------------------------------------+}}
> The two-column output schema is unchanged; only new rows are added, and only
> when the underlying TypeInference carries that metadata. No new SQL syntax.
> Out of Scope
> - New columns or a new SQL keyword (e.g. DESCRIBE FUNCTION ... STATE). Can
> be considered separately if needed; would require a FLIP.
> - Changes to non-EXTENDED DESCRIBE FUNCTION output.
> Acceptance Criteria
> - New rows produced for PTFs and any other functions whose TypeInference
> exposes static arguments / state.
> - No change in output for scalar/aggregate/table functions that don't
> expose this metadata.
> - Tests in DescribeFunctionOperationTest (or equivalent) cover a PTF with
> state + traited arguments.
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