public void deleteKVConfig(final String namespace, final String key) {
        try {
            this.lock.writeLock().lockInterruptibly();
            try {
                HashMap<String, String> kvTable = this.configTable.get(namespace);
                if (null != kvTable) {
                    String value = kvTable.remove(key);
                    log.info("deleteKVConfig delete a config item, Namespace: {} Key: {} Value: {}",
                        namespace, key, value);
                }
            } finally {
                this.lock.writeLock().unlock();
            }
        } catch (InterruptedException e) {
            log.error("deleteKVConfig InterruptedException", e);
        }

        this.persist();
    }
@Test
    public void testDeleteKVConfig() {
        kvConfigManager.deleteKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG, "UnitTest");
        byte[] kvConfig = kvConfigManager.getKVListByNamespace(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG);
        assertThat(kvConfig).isNull();
        Assert.assertTrue(kvConfig == null);
        String value = kvConfigManager.getKVConfig(NamesrvUtil.NAMESPACE_ORDER_TOPIC_CONFIG, "UnitTest");
        assertThat(value).isNull();
    }