07.10.2014, 19:59, "Tom Lane" <tgl@xxxxxxxxxxxxx>: > Vladimir Kamarzin <vvk@xxxxxxxxx> writes: >> After upgrade from 9.3.1 to 9.3.5 we expirienced a slight performance degradation of all queries. Query time increased to some amount of ms, mostly in range of 100ms. Some actions in our application results in a lot of small queries and in such cases performance degradation is very significant - total action performs for a 2-3 times longer then before (15s -> 40s, etc). >> Using git-bisect we've found a bad revision causes performance drop: it is 324577f39bc8738ed0ec24c36c5cb2c2f81ec660 > > Hm. If you're going to do queries that involve update/delete across large > inheritance trees, that bug fix is unavoidably going to cost you some > cycles. Yeah, we're actually noticed significantly increased CPU load while running on 9.3.5. > I am wondering if you've > misidentified the commit that made the difference --- especially since you > claim there's a penalty for "all" queries, which there manifestly couldn't > be with this particular patch. No, problem appears exactly on this commit. Actually I don't really sure about "all": we don't see degradation when performing plain SELECTs manually, but comparing logged query time of some SELECTs we see the differences. Here is example 42ms -> 250ms: http://pastebin.ca/2855292 http://pastebin.ca/2855290 > If not, there must be something rather > unusual about your queries or schema. Care to provide a self-contained > test case? I'm afraid we cannot do this now. If you wish, we can give you ssh access to the test server to investigate the problem. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
