From: David Rowley [mailto:david.row...@2ndquadrant.com] > Another counter-argument to this is that there's already an > unexplainable slowdown after you run a query which obtains a large > number of locks in a session or use prepared statements and a > partitioned table with the default plan_cache_mode setting. Are we not > just righting a wrong here? Albeit, possibly 1000 queries later. > > I am, of course, open to other ideas which solve the problem that v5 > has, but failing that, I don't see v6 as all that bad. At least all > the logic is contained in one function. I know Tom wanted to steer > clear of heuristics to reinitialise the table, but most of the stuff > that was in the patch back when he complained was trying to track the > average number of locks over the previous N transactions, and his > concerns were voiced before I showed the 7% performance regression > with unconditionally rebuilding the table.
I think I understood what you mean. Sorry, I don't have a better idea. This unexplanability is probably what we should accept to avoid the shocking 7% slowdown. OTOH, how about my original patch that is based on the local lock list? I expect that it won't that significant slowdown in the same test case. If it's not satisfactory, then v6 is the best to commit. Regards Takayuki Tsunakawa
