preserve threads we've participated in

honk.go

@@ -1342,8 +1342,8 @@ func cleanupdb() {
 		}
 	}
 	expdate := time.Now().UTC().Add(-30 * 24 * time.Hour).Format(dbtimeformat)
-	doordie(db, "delete from donks where honkid in (select honkid from honks where dt < ? and whofore = 0)", expdate)
-	doordie(db, "delete from honks where dt < ? and whofore = 0", expdate)
+	doordie(db, "delete from donks where honkid in (select honkid from honks where dt < ? and whofore = 0 and convoy not in (select convoy from honks where whofore = 2 or whofore = 3))", expdate)
+	doordie(db, "delete from honks where dt < ? and whofore = 0 and convoy not in (select convoy from honks where whofore = 2 or whofore = 3)", expdate)
 	doordie(db, "delete from files where fileid not in (select fileid from donks)")
 }