Hi, all My name is Mengxing Liu. I am interested in the project "Eliminate O(N^2) scaling from rw-conflict tracking in serializable transactions”. After discussing with Kevin off-list, I think it's time to post discussion here. I am afraid that there are two things that I need your help. Thank you very much.
> > > So the task is clear. We can use a tree-like or hash-like data > > structure to speed up this function. > > Right -- especially with a large number of connections holding a > large number of conflicts. In one paper with high concurrency, they > found over 50% of the CPU time for PostgreSQL was going to these > functions (including functions called by them). This seems to me to > be due to the O(N^2) (or possibly worse) performance from the number > of connections. Anyone knows the title of this paper? I want to reproduce its workloads. > > Remember, I think most of the work here is going to be in > benchmarking. We not only need to show improvements in simple test > cases using readily available tools like pgbench, but think about > what types of cases might be worst for the approach taken and show > that it still does well -- or at least not horribly. It can be OK > to have some slight regression in an unusual case if the common > cases improve a lot, but any large regression needs to be addressed > before the patch can be accepted. There are some community members > who are truly diabolical in their ability to devise "worst case" > tests, and we don't want to be blind-sided by a bad result from one > of them late in the process. > Are there any documents or links introducing how to test and benchmark PostgreSQL? I may need some time to learn about it. Thanks. -- Mengxing Liu -- Sent via pgsql-hackers mailing list (email@example.com) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers