Module writer_task 

Single-writer task and bounded write queue (ADR-067 Component A). Single-writer task and bounded write queue (ADR-067 Component A).

WriterTask (via spawn and the drain loop run_writer_task) owns a dedicated standalone writer rusqlite::Connection and is the only code path that issues BEGIN IMMEDIATE for write traffic routed through the channel it drains. Callers reach it exclusively through a WriterTaskHandle, sending a typed closure and awaiting a typed oneshot reply so each store method’s natural return type (e.g. BatchWriteSummary) survives the trip through the type-erased channel unmodified — a flat Result<u64, StorageError> reply would conflate affected/failed into one count and drop first_error.

See crates/khive-db/docs/api/writer-task.md for migration-slice scope (which write paths currently route through this vs. the legacy pool-mutex path) and the ADR-067 component breakdown.

Structs

WriteRequest

One write request awaiting execution by the writer task.

WriterTaskHandle

Sender half of the write queue. Cheaply cloneable (wraps an mpsc::Sender) — every migrated store that shares one writer task holds a clone of this handle.

Traits

AnyWriteRequest

Type-erased write request the writer task’s drain loop can hold in a homogeneous channel (mpsc::Sender<Box<dyn AnyWriteRequest + Send>>), while each concrete WriteRequest<R> still carries its own typed reply. Sealed: only this module may implement it (ADR-067 lines 210-212).

Functions

spawn

Spawn the write-owner task (ADR-067 Component A) on the current Tokio runtime.