Hi Mike, Thanks for the details. Yes, besides another mysql server running on the same server, there is also an homegrown application that frequent read/write the file system. The postgres shared cache is at 4G, is that too big? Thanks Sean On Tue, Jun 30, 2009 at 1:23 PM, Mike Ivanov<mikei@xxxxxxxxxxxxxxx> wrote: > Hi Sean, > > Well, the overall impression is your machine is badly overloaded. Look: > >> top - 10:18:58 up 224 days, 15:10, 2 users, load average: 6.27, 7.33, 6 >> > > The load average of 6.5 means there are six and a half processes competing > for the same CPU (and this system apparently has only one). This > approximately equals to 500% overload. > > Recommendation: either add more CPU's or eliminate process competition by > moving them to other boxes. > >> Tasks: 239 total, 1 running, 238 sleeping, 0 stopped, 0 zombie >> > > This supports what I said above. There are only 92 processes running on my > laptop and I think it is too much. Do you have Apache running on the same > machine? > >> Cpu(s): 5.0%us, 0.7%sy, 0.0%ni, 61.5%id, 32.7%wa, 0.0%hi, 0.1%si, 0 >> > > Waiting time (wa) is rather high, which means processes wait on locks or for > IO, another clue for concurrency issues on this machine. > >> Mem: 32962804k total, 32802612k used, 160192k free, 325360k buffers >> > > Buffers are about 10% of all the memory which is OK, but I tend to give > buffers some more room. > > Recommendation: eliminate unneeded processes, decrease (yes, decrease) the > Postgres cache buffers if they are set too high. > >> Swap: 8193140k total, 224916k used, 7968224k free, 30829456k cached >> > > 200M paged out. It should be zero except of an emergency. 3G of cached swap > is a sign of some crazy paging activity in thepast. Those unexplainable > slowdowns are very likely caused by that. > >> Didn't really see the pattern, typical the cpu load is only about 40% >> > > 40% is too much, really. I start worrying when it is above 10%. > > Conclusion: > > - the system bears more load than it can handle > - the machine needs an upgrade > - Postges is competing with something (presumably Apache) - separate them. > > That should help. > > Cheers, > Mike > > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
