sqlite: add backoff consts

persist/sqlite/consts_default.go

@@ -2,4 +2,8 @@
 
 package sqlite
 
-const busyTimeout = 5000 // 5 seconds
+const (
+	busyTimeout   = 5000 // 5 seconds
+	retryAttempts = 15   // 15 attempts
+	factor        = 2.0  // factor ^ retryAttempts = backoff time in milliseconds
+)

persist/sqlite/consts_testing.go

@@ -2,4 +2,8 @@
 
 package sqlite
 
-const busyTimeout = 100 // 100ms
+const (
+	busyTimeout   = 5   // 5ms
+	retryAttempts = 10  // 10 attempts
+	factor        = 2.0 // factor ^ retryAttempts = backoff time in milliseconds
+)

persist/sqlite/store.go

@@ -83,7 +83,7 @@ func (s *Store) queryRow(query string, args ...any) *loggedRow {
 func (s *Store) transaction(fn func(txn) error) error {
 	var err error
 	log := s.log.Named("transaction")
-	for i := 1; i <= 15; i++ {
+	for i := 1; i <= retryAttempts; i++ {
 		start := time.Now()
 		log := log.With(zap.Int("attempt", i))
 		err = doTransaction(s.db, log, fn)
@@ -98,8 +98,8 @@ func (s *Store) transaction(fn func(txn) error) error {
 			return err
 		}
 		log.Debug("database locked", zap.Duration("elapsed", time.Since(start)), zap.Stack("stack"))
-		sleep := time.Duration(math.Pow(2, float64(i))) * time.Millisecond // exponential backoff for a total of ~30s
-		time.Sleep(sleep + time.Duration(rand.Int63n(int64(sleep)/10)))
+		sleep := time.Duration(math.Pow(factor, float64(i))) * time.Millisecond // exponential backoff
+		time.Sleep(sleep + time.Duration(rand.Int63n(int64(sleep)/10)))         // add random jitter
 	}
 	return fmt.Errorf("transaction failed: %w", err)
 }

persist/sqlite/store_test.go

@@ -68,7 +68,7 @@ func TestTransactionRetry(t *testing.T) {
 					return err
 				}
 				ch <- struct{}{}
-				time.Sleep(10 * time.Second)
+				time.Sleep(2 * time.Second)
 				return nil
 			})
 			if err != nil {