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DuckDB Extensions All extensions VGI

Workers & pooling functions in the VGI DuckDB extension

Function category

Workers & pooling

2 functions

Inspect VGI's subprocess worker pool — which workers are alive and how often pooled workers are reused.

vgi_worker_pool

Table function Workers & pooling
Signature
vgi_worker_pool() → None
Returns

A table with the following columns:

Column worker_path Type VARCHAR Description Executable path of the pooled worker.
Column data_version_spec Type VARCHAR Description Data version the pooled worker reports.
Column implementation_version Type VARCHAR Description Implementation version the pooled worker reports.
Column pid Type BIGINT Description Operating-system process id of the worker subprocess.
Column age_seconds Type BIGINT Description How long the worker has been alive in the pool, in seconds.
Description

List the VGI worker subprocesses currently pooled for reuse by this DuckDB process, one row per worker with its path, version info, pid, and idle age in seconds. Useful for capacity planning and spotting stale workers. Returns no rows for launch: / unix:// transports, whose workers are pooled by the OS-level AF_UNIX socket rather than this DuckDB process.

1 Example 1 
SELECT * FROM vgi_worker_pool();

vgi_worker_pool_stats

Table function Workers & pooling
Signature
vgi_worker_pool_stats() → None
Returns

A table with the following columns:

Column worker_path Type VARCHAR Description Executable path of the worker.
Column hits Type UBIGINT Description Number of times a pooled worker was reused for this path.
Column misses Type UBIGINT Description Number of times a new worker had to be started for this path.
Description

Report worker-pool reuse effectiveness, one row per worker_path with how many acquisitions reused a pooled worker (hits) versus spawned a fresh one (misses). A low hit rate suggests workers are being evicted before reuse. Subprocess transport only.

1 Example 1 
SELECT * FROM vgi_worker_pool_stats();