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DuckDB Extensions All extensions VGI

Worker access functions in the VGI DuckDB extension

Function category

Worker access

3 functions

Reach a VGI worker directly — discover the catalogs it advertises and run its table functions or table scans — without `ATTACH`ing it as a database.

vgi_catalogs

Table function Worker access
Signature
vgi_catalogs(worker_path: VARCHAR) → None
Arguments (Positional)
Argument worker_path Type VARCHAR Mode Positional Description
Returns

A table with the following columns:

Column catalog Type VARCHAR Description Name of the catalog as the worker advertises it.
Column implementation_version Type VARCHAR Description Version string of the worker implementation serving this catalog.
Column data_version_spec Type VARCHAR Description Data-version specifier the worker reports for this catalog.
Column attach_options Type STRUCT[] Description Options the catalog accepts on ATTACH. Each entry has name, description, type, and default_value.
Column releases Type STRUCT[] Description Release history the worker advertises. Each entry has version, released_at, summary, and notes_url.
Column source_url Type VARCHAR Description URL of the worker's source or documentation, if provided.
Description

List the catalogs advertised by a VGI worker, one row per catalog with its name and description. Use this to discover what a worker exposes before ATTACHing it.

1 Example 1 
SELECT * FROM vgi_catalogs('./worker');

vgi_table_function

Table function Worker access
Signature
2 overloaded forms · click to inspect
Arguments (Positional)
Argument worker_path Type VARCHAR Mode Positional Description
Argument function_name Type VARCHAR Mode Positional Description
Argument positional_args Type ANY[] Mode Positional Description
Returns

The output columns are whatever the worker-side table function function_name produces. The schema is resolved at bind time from the worker's response, so it varies by function and worker.

Dynamic schema. The output columns are determined at bind time and vary per call, so they aren't listed here.

Description

Directly execute a table function exposed by a VGI worker, without ATTACHing it as a catalog. Pass the worker executable path, the worker-side function name, the positional arguments as a LIST, and optionally a STRUCT of named arguments.

1 Call a worker function with positional arguments 
SELECT * FROM vgi_table_function('./worker', 'projected_data', [10]);
2 Pass an options struct (quote reserved field names) 
SELECT * FROM vgi_table_function('./worker', 'projected_data', [10], {'limit': 5});

vgi_table_scan

Table function Worker access
Signature
vgi_table_scan() → None
Returns

The output columns mirror the schema of the attached VGI table being scanned. The schema is resolved at bind time from the worker, so it varies per table.

Dynamic schema. The output columns are determined at bind time and vary per call, so they aren't listed here.

Description

Internal: the physical scan operator for tables in an attached VGI catalog. DuckDB binds it automatically when you query a VGI table (SELECT ... FROM mycatalog.schema.table); it exists in the function list only so serialized query plans can resolve it by name. It takes no arguments and cannot be called directly — use a normal table reference instead.