Method releaseSem

server/attach_timeout.go:172–192

releaseSem returns the attach semaphore slot acquired by the caller. If any statement was abandoned past its deadline, the release is handed to a goroutine that waits for the underlying CGO call(s) to actually finish first — the semaphore exists to serialize attach work on the database, and a hung A

(sem chan struct{})

//
// No-op when sem is nil (callers that run without the semaphore).
func (a *attachStepExecer) releaseSem(sem chan struct{}) {
	if sem == nil {
		return
	}
	a.mu.Lock()
	abandoned := a.abandoned
	a.abandoned = nil
	a.mu.Unlock()
	if len(abandoned) == 0 {
		<-sem
		return
	}
	go func() {
		for _, st := range abandoned {
			<-st.done
		}
		slog.Warn("Abandoned catalog attachment statement(s) finished; releasing attach semaphore.",
			"count", len(abandoned))
		<-sem
	}()
}

// attachSQLRunner abstracts the statement runner shared by createS3SecretWith
// so catalog-attachment paths run under per-step deadlines (attachStepExecer)