chore(sqlite): allow periodic database maintenance to be disabled (#10441)

This change allows the periodic database maintenance to be disabled, while providing a way to programmatically start maintenance at a convenient moment.

Signed-off-by: Tommy van der Vorst <tommy@pixelspark.nl>

internal/db/sqlite/db_service.go

@@ -19,7 +19,6 @@ import (
 	"github.com/syncthing/syncthing/internal/db"
 	"github.com/syncthing/syncthing/internal/slogutil"
 	"github.com/syncthing/syncthing/lib/protocol"
-	"github.com/thejerf/suture/v4"
 )
 
 const (
@@ -32,7 +31,7 @@ const (
 	gcMaxRuntime = 5 * time.Minute // max time to spend on gc, per table, per run
 )
 
-func (s *DB) Service(maintenanceInterval time.Duration) suture.Service {
+func (s *DB) Service(maintenanceInterval time.Duration) db.DBService {
 	return newService(s, maintenanceInterval)
 }
 
@@ -40,6 +39,7 @@ type Service struct {
 	sdb                 *DB
 	maintenanceInterval time.Duration
 	internalMeta        *db.Typed
+	start               chan struct{}
 }
 
 func (s *Service) String() string {
@@ -51,12 +51,19 @@ func newService(sdb *DB, maintenanceInterval time.Duration) *Service {
 		sdb:                 sdb,
 		maintenanceInterval: maintenanceInterval,
 		internalMeta:        db.NewTyped(sdb, internalMetaPrefix),
+		start:               make(chan struct{}),
+	}
+}
+
+func (s *Service) StartMaintenance() {
+	select {
+	case s.start <- struct{}{}:
+	default:
 	}
 }
 
 func (s *Service) Serve(ctx context.Context) error {
 	// Run periodic maintenance
-
 	// Figure out when we last ran maintenance and schedule accordingly. If
 	// it was never, do it now.
 	lastMaint, _, _ := s.internalMeta.Time(lastMaintKey)
@@ -66,21 +73,29 @@ func (s *Service) Serve(ctx context.Context) error {
 		wait = time.Minute
 	}
 	slog.DebugContext(ctx, "Next periodic run due", "after", wait)
-
 	timer := time.NewTimer(wait)
+
+	if s.maintenanceInterval == 0 {
+		timer.Stop()
+	}
+
 	for {
 		select {
 		case <-ctx.Done():
 			return ctx.Err()
 		case <-timer.C:
+		case <-s.start:
 		}
 
 		if err := s.periodic(ctx); err != nil {
 			return wrap(err)
 		}
 
-		timer.Reset(s.maintenanceInterval)
-		slog.DebugContext(ctx, "Next periodic run due", "after", s.maintenanceInterval)
+		if s.maintenanceInterval != 0 {
+			timer.Reset(s.maintenanceInterval)
+			slog.DebugContext(ctx, "Next periodic run due", "after", s.maintenanceInterval)
+		}
+
 		_ = s.internalMeta.PutTime(lastMaintKey, time.Now())
 	}
 }