Re: heavy load-high cpu itilization

On Jul 30, 2011, at 3:02 PM, Filippos wrote:
> thx a lot for your answer.
> i will provide some stats, so if you could help me figure out the source of
> the problem that would be great
>
> -*top -c*
> Tasks: 1220 total, 49 running, 1171 sleeping, 0 stopped, 0 zombie
> Cpu(s): *84.1%us*, 2.8%sy, 0.0%ni, 12.3%id, 0.1%wa, 0.1%hi, 0.6%si,
> 0.0%st
> Mem: 98846996k total, 98632044k used, 214952k free, 134320k buffers
> Swap: 50331640k total, 116312k used, 50215328k free, 89445208k cached

84% CPU isn't horrible, and you do have idle CPU time available. So you don't look to be too CPU-bound, although you need to keep in mind that one process might be CPU intensive and taking a long time to run, thereby blocking other processes that depend on it's results.

> -SELECT count(procpid) FROM pg_stat_activity -> *422*
> -SELECT count(procpid) FROM pg_stat_activity WHERE (NOW() - query_start) >
> INTERVAL '1 MINUTES' AND current_query = '<IDLE>' -> *108*
> -SELECT count(procpid) FROM pg_stat_activity WHERE (NOW() - query_start) >
> INTERVAL '5 MINUTES' AND current_query = '<IDLE>' -> *45*

It would be good to look at getting some connection pooling happening.

Your vmstat output shows you generally have CPU available. Can you provide some output from iostat -xk 2?

> -*vmstat -n 1 10*
> procs -----------memory---------- ---swap-- -----io---- --system--
> -----cpu------
> r b swpd free buff cache si so bi bo in cs us sy id
> wa st
> 41 1 116300 347008 134176 89608912 0 0 143 210 0 0 11 1 88
> 0 0
> 20 0 116300 423556 134116 89581840 0 0 8336 3038 11118 21139 81 5
> 13 0 0
> 24 0 116300 412904 134108 89546840 0 0 8488 9025 10621 22921 81 4
> 15 0 0
> 23 0 116300 409388 134084 89513728 0 0 8320 548 11386 20226 82 4
> 14 0 0
> 34 0 116300 403688 134088 89509520 0 0 6336 0 9552 20994 83 3
> 14 0 0
> 22 1 116300 337972 134104 89518624 0 0 8792 28 8980 20455 83 4
> 13 0 0
> 37 0 116300 303956 134116 89528720 0 0 8440 536 9644 20492 84 3
> 13 0 0
> 17 1 116300 293212 134112 89532816 0 0 5864 8240 9527 19771 85 3
> 12 0 0
> 14 0 116300 282168 134116 89540720 0 0 7772 752 10141 21780 84 3
> 13 0 0
> 44 0 116300 278684 134100 89536080 0 0 7352 555 9856 21539 85 2
> 13 0 0
>
> -*vmstat -s*
> 98846992 total memory
> 98685392 used memory
> 40342200 active memory
> 52644588 inactive memory
> 161604 free memory
> 129960 buffer memory
> 89421936 swap cache
> 50331640 total swap
> 116300 used swap
> 50215340 free swap
> 2258553017 non-nice user cpu ticks
> 1125281 nice user cpu ticks
> 146638389 system cpu ticks
> 17789847697 idle cpu ticks
> 83090716 IO-wait cpu ticks
> 5045742 IRQ cpu ticks
> 38895985 softirq cpu ticks
> 0 stolen cpu ticks
> 29142450583 pages paged in
> 42731005078 pages paged out
> 39784 pages swapped in
> 3395187 pages swapped out
> 1338370564 interrupts
> 1176640487 CPU context switches
> 1305704895 boot time
> 24471946 forks
>
> (after 30 sec)
> -*vmstat -s*
> 98846992 total memory
> 98367312 used memory
> 39959952 active memory
> 52957104 inactive memory
> 479684 free memory
> 129720 buffer memory
> 89410640 swap cache
> 50331640 total swap
> 116296 used swap
> 50215344 free swap
> 2258645091 non-nice user cpu ticks
> 1125282 nice user cpu ticks
> 146640181 system cpu ticks
> 17789863186 idle cpu ticks
> 83090856 IO-wait cpu ticks
> 5045855 IRQ cpu ticks
> 38896749 softirq cpu ticks
> 0 stolen cpu ticks
> 29142861271 pages paged in
> 42731249289 pages paged out
> 39784 pages swapped in
> 3395187 pages swapped out
> 1338808821 interrupts
> 1177463384 CPU context switches
> 1305704895 boot time
> 24472003 forks
>
> from the above -> context switches /s = (1177463384 - 1176640487)/30 =
> *27429*
>
> thx in advance for any advice
>
>
>
>
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--
Jim C. Nasby, Database Architect jim(at)nasby(dot)net
512.569.9461 (cell) http://jim.nasby.net