public StorageID append(String name, long value) {
        if (StringUtil.isBlank(name)) {
            throw new IllegalArgumentException("The name of storage ID should not be null or empty.");
        }
        if (sealed) {
            throw new IllegalStateException("The storage ID is sealed. Can't append a new fragment, name=" + name);
        }
        fragments.add(new Fragment(new String[] {name}, Long.class, false, value));
        return this;
    }
The string ID would only be built once.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/storage/StorageID.java