> ## Documentation Index
> Fetch the complete documentation index at: https://headgate.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# SQLite

> Embedded durable storage with transactional policy admission and bounded inspection.

SQLite implements Headgate's complete worker store in both Rust and Go. It evaluates
policy, selects work, spends rate capacity, and writes the state, lease, and fence inside
one `BEGIN IMMEDIATE` transaction. The adapter is intended for embedded applications,
local development, and small fleets whose write load fits SQLite's single-writer model.

<CodeGroup>
  ```rust Rust theme={"system"}
  let store = std::sync::Arc::new(
      headgate_sqlite::SqliteStore::open("headgate.db").await?
  );
  ```

  ```go Go theme={"system"}
  store, err := headgatesqlite.Open(ctx, "headgate.db")
  if err != nil {
      return err
  }
  defer store.Close()
  ```
</CodeGroup>

## Capabilities

SQLite advertises transactions and inspection. This includes transactional enqueue and
completion, effects and checkpoints, results, output, progress, schedules, durable events,
workers, queue controls, quarantine, and bounded bulk operations.

SQLite deliberately does not advertise notifications. Workers use Headgate's bounded
poll/backoff loop; pretending a polling table were push notification would make the
capability contract misleading.

## Connection behavior

* File databases use WAL, foreign keys, and a bounded busy timeout.
* `:memory:` uses one physical connection so the database is not split across a pool.
* Store time—not caller time—drives leases, scheduling, token refill, and duties.
* A bare Go filename is converted to a SQLite file URI before driver options are added.
* The matching embedded schema is installed when the adapter opens. Rust and Go schema
  bytes are checked for drift by the repository verification gate.

## Standalone control API

Set `HG_STORE=sqlite` and optionally `HG_SQLITE=/path/to/headgate.db`. Both standalone APIs
serve the same control API and embedded console as the other inspection-capable backends.

<Note>
  The shared cross-language corpus runs SQLite through both store implementations and covers
  fleet-wide rate limiting, fairness under a 5,000-job tenant flood, quarantine, atomic
  leases, store-clock behavior, and concurrent no-double-claim admission.
</Note>

<Card title="SQLite implementation contract" icon="file-check" href="https://github.com/mujhtech/headgate/blob/main/docs/sqlite-store.md" />