Aftab Ahmed Chandio wrote > I found 85 ms time unit in DOS (win7) (laptop 4cores). both Java and > PostgreSQL installed and invoked on the same machine, respectively. > On the other hand, I use same process (separate installation) on linux on > 8 cores physical machine with 2times greater then laptop. > I found 150 ms. (which is a question for me because the time in Linux > environment should give me half of the time taking on laptop) I'm not particularly performance measuring experienced but a few items come to mind: A single (or handful) of manual runs is not going to provide good data for comparison Hard drive characteristics can make a difference A single query uses a single process/thread so core count is irrelevant RAM is likely immaterial though depends heavily on the dataset These last two factors is why your "2times greater" system is in fact nearly identical to the laptop with respect to its ability to run and single query. Your Linux system is probably capable of handling twice the data and simultaneous connections but each connection is limited. Lastly, the execution times - while relatively different - are both quite small and subject to considerable system noise - which is why a single run is insufficient to draw conclusions. I'm not really sure what kind of positive response you want. There may be room to improve the Linux setup, and using the same configuration on two difference OS is not going to mean they should be expected to provide the same performance, but you need to be much more detailed in what you are testing and your measurement procedure if you expect any actionable advice. In order to do performance tuning you need to setup a realistic environment within with to perform measurements. You are either lacking that or have failed to describe it adequately. Once you can measure those measurements will guide you to where to need to either tweak settings or improve hardware. Finally, the ability and need for configuration changes is highly dependent upon the version of PostgreSQL you are running - that should be the first thing you disclose. And then, you presume that it is differences in PostgreSQL that are to be solved but you have the entire Java VM to be concerned with as well. Running your queries in psql removes that variable and helps pin-point where the tuning likely needs to occur. David J. -- View this message in context: http://postgresql.1045698.n5.nabble.com/postgreSQL-query-via-JDBC-in-different-OS-taking-different-running-time-tp5773618p5773637.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
