I installed the plugin in my website. It seems quite good and reduce much sql query.
without Query Cache: 2000+ queries;
with Query Cache v1.6: about 500 queries;

But now a problem is happening. My website in browser will show following wrong code when I upload a product to my store.

1062 Duplicate entry '4404c1df54fdb1291c8dd9bb259f32a9-1' for key 1
in:
[INSERT INTO seo_cache (cache_id, cache_language_id, cache_name, cache_data, cache_global, cache_gzip, cache_method, cache_date, cache_expires) VALUES ('4404c1df54fdb1291c8dd9bb259f32a9', '1', 'seo_urls_v2_manufacturers', 'AwA=', '1', '1', 'EVAL', '2015-04-25 04:37:54', '2015-05-25 04:37:54')]

The above wrong code only shows one time on browser, after I upload a new product into my store. And then my website is OK if I repeat to click any page. Please anyone has ever met the same issue, or any advise regarding above wrong code.

So far, I still have not got any solution... Any advise from any buddy!!!