On Fri, Sep 19, 2008 at 5:55 AM, c k <shreeseva.learning@xxxxxxxxx> wrote: > Hello PG Community, > Does PG uses multiple processors/cores if available by default on various > OSes? Yes, see attached top extract from my primary db server at work > What are the limitations on using multiple processors/cores and main > memory? Do you mean how many CPUs and how much memory? no real limits on a 64 bit machine. Note that it's often better to let the os do the majority of caching, depending on your work load. This is especially true in OLTP where the cost of pgsql maintaining a large buffer is higher than the benefit it provides, but the kernel can cache much larger datasets faster, in my experience.
top - 08:27:03 up 38 days, 19:10, 1 user, load average: 3.67, 4.26, 4.39 Tasks: 316 total, 8 running, 308 sleeping, 0 stopped, 0 zombie Cpu0 : 10.4%us, 0.9%sy, 0.0%ni, 88.7%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu1 : 21.6%us, 5.2%sy, 0.0%ni, 73.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu2 : 4.3%us, 1.7%sy, 0.0%ni, 93.1%id, 0.0%wa, 0.0%hi, 0.9%si, 0.0%st Cpu3 : 14.8%us, 0.9%sy, 0.0%ni, 83.5%id, 0.0%wa, 0.0%hi, 0.9%si, 0.0%st Cpu4 : 51.3%us, 2.6%sy, 0.0%ni, 46.1%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu5 : 47.8%us, 2.6%sy, 0.0%ni, 48.7%id, 0.0%wa, 0.0%hi, 0.9%si, 0.0%st Cpu6 : 57.4%us, 2.6%sy, 0.0%ni, 40.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Cpu7 : 62.6%us, 4.3%sy, 0.0%ni, 26.1%id, 0.0%wa, 0.9%hi, 6.1%si, 0.0%st Mem: 33031252k total, 30858572k used, 2172680k free, 521644k buffers Swap: 9767480k total, 8032k used, 9759448k free, 27457352k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 13827 postgres 16 0 8353m 112m 103m R 37 0.3 0:01.37 postgres: webguy www 10.0.0.59(43081) SELECT 11115 postgres 15 0 8363m 2.0g 2.0g R 32 6.3 7:44.41 postgres: webguy www 10.0.0.58(42066) SELECT 13651 postgres 15 0 8358m 426m 416m S 25 1.3 0:04.70 postgres: webguy www 10.0.0.52(59220) idle 13746 postgres 15 0 8360m 396m 384m S 20 1.2 0:03.44 postgres: webguy www 10.0.0.58(53244) idle 13775 postgres 15 0 8357m 403m 394m S 20 1.3 0:03.25 postgres: webguy www 10.0.0.59(38550) idle 13840 postgres 15 0 8355m 138m 130m S 16 0.4 0:01.81 postgres: webguy www 10.0.0.58(60554) idle 13813 postgres 16 0 8357m 372m 362m R 13 1.2 0:02.44 postgres: webguy www 10.0.0.59(41723) SELECT 13893 postgres 15 0 8349m 28m 25m S 10 0.1 0:00.14 postgres: webguy www 10.0.0.52(47776) idle 13598 postgres 15 0 8360m 566m 553m S 9 1.8 0:12.42 postgres: webguy www 10.0.0.59(55696) idle 13854 postgres 15 0 8355m 92m 84m S 9 0.3 0:00.90 postgres: webguy www 10.0.0.59(44909) idle 13718 postgres 15 0 8358m 437m 426m S 8 1.4 0:08.55 postgres: webguy www 10.0.0.59(34177) idle 13794 postgres 15 0 8354m 32m 27m S 8 0.1 0:00.26 postgres: webguy www 10.0.0.153(36273) idle 13820 postgres 15 0 8358m 194m 184m S 8 0.6 0:02.03 postgres: webguy www 10.0.0.58(58962) idle 13791 postgres 15 0 8359m 258m 246m S 7 0.8 0:04.30 postgres: webguy www 10.0.0.59(40007) idle 13439 postgres 15 0 8358m 604m 594m S 6 1.9 0:10.06 postgres: webguy www 10.0.0.58(33212) idle 13570 postgres 16 0 8359m 322m 311m S 6 1.0 0:09.51 postgres: webguy www 10.0.0.58(41747) idle 13736 postgres 15 0 8359m 300m 289m S 6 0.9 0:04.50 postgres: webguy www 10.0.0.59(36212) idle 13809 postgres 15 0 8351m 229m 219m R 5 0.7 0:02.05 postgres: webguy www 10.0.0.58(57974) SELECT
