fix: checkpoint initialization gap on restarts

Entire-Checkpoint: 3f4d366b037c

pkg/metricstore/archive.go

@@ -53,6 +53,16 @@ func cleanUpWorker(wg *sync.WaitGroup, ctx context.Context, interval string, mod
 			return
 		}
 
+		// Account for checkpoint span: files named {from}.bin contain data up to
+		// from+checkpointInterval. Subtract the checkpoint interval so we don't
+		// delete files whose data still falls within the retention window.
+		checkpointSpan := 12 * time.Hour
+		if Keys.CheckpointInterval != "" {
+			if parsed, err := time.ParseDuration(Keys.CheckpointInterval); err == nil {
+				checkpointSpan = parsed
+			}
+		}
+
 		ticker := time.NewTicker(d)
 		defer ticker.Stop()
 
@@ -61,7 +71,7 @@ func cleanUpWorker(wg *sync.WaitGroup, ctx context.Context, interval string, mod
 			case <-ctx.Done():
 				return
 			case <-ticker.C:
-				t := time.Now().Add(-d)
+				t := time.Now().Add(-d).Add(-checkpointSpan)
 				cclog.Infof("[METRICSTORE]> start %s checkpoints (older than %s)...", mode, t.Format(time.RFC3339))
 
 				n, err := CleanupCheckpoints(Keys.Checkpoints.RootDir, cleanupDir, t.Unix(), delete)