Re: high load on server

On Apr 3, 2009, at 7:32 AM, Scott Marlowe wrote:

> 2009/4/3 Gerd König <koenig(at)transporeon(dot)com>:
>> Hello,
>>
>> since 2 days ago we're facing an increased load on our database
>> server
>> (opensuse10.3-64bit, PostgreSQL 8.3.5, 8GB Ram). This high load
>> stays the whole
>> working day.
>
> How man cores?
>
>> ==================
>> current situation:
>> ==================
>> #>top
>> top - 14:09:46 up 40 days, 8:08, 2 users, load average: 7.60,
>> 7.46, 7.13
>> ...
>> Mem: 8194596k total, 5716680k used, 2477916k free, 185516k
>> buffers
>> Swap: 4200988k total, 204k used, 4200784k free, 5041448k
>> cached
>>
>> PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
>> 17478 postgres 15 0 610m 455m 444m R 52 5.7 0:08.78
>> postmaster
>> 17449 postgres 15 0 606m 497m 489m S 37 6.2 0:16.35
>> postmaster
>> 22541 postgres 16 0 607m 522m 516m R 31 6.5 123:25.17
>> postmaster
>> 17491 postgres 15 0 618m 447m 435m S 22 5.6 0:03.97
>> postmaster
>> 17454 postgres 15 0 616m 474m 457m S 18 5.9 0:15.88
>> postmaster
>> 22547 postgres 15 0 608m 534m 527m S 18 6.7 100:12.01
>> postmaster
>> 17448 postgres 16 0 616m 517m 501m S 17 6.5 0:15.60
>> postmaster
>> 17451 postgres 15 0 611m 491m 479m S 11 6.1 0:25.04
>> postmaster
>> 17490 postgres 15 0 606m 351m 344m S 10 4.4 0:02.69
>> postmaster
>> 22540 postgres 15 0 607m 520m 513m S 2 6.5 33:46.47
>> postmaster
>> 17489 postgres 15 0 604m 316m 311m S 2 4.0 0:03.34
>> postmaster
>
> Next time hit c first to see what the postmasters are up to.
>
>> I assume the problem is caused by heavy writing slows down the
>> server....?!?...why?=>
>
> The problem might be that you're assuming there's a problem. Looking
> at the rest of your diags, you're data set fits in memory, I/O wait is
> < 10% and there are no processes waiting for a CPU to free up, they're
> all running.
>
> Looks healthy to me.

Eh? His run queue constantly has procs waiting for run time, although
I've seen higher. That with a distinct lack of heavy IO says cpu
bound to me...

#>vmstat 2 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----
cpu----
r b swpd free buff cache si so bi bo in cs us sy
id wa
5 0 204 2449652 185692 5046168 0 0 2 24 1 1 2
0 95 2
3 0 204 2448496 185692 5046184 0 0 0 518 2984 18683
24 5 65 6
3 0 204 2430864 185692 5046192 0 0 0 344 2083 10004
34 3 58 5
2 0 204 2434600 185700 5046200 0 0 0 386 2084 23592
33 3 57 7
3 0 204 2425612 185700 5046220 0 0 0 372 2352 2905 36
2 57 5
5 0 204 2424828 185700 5046256 0 0 0 600 2372 33094 36
12 48 4
4 0 204 2405516 185700 5046256 0 0 4 992 1747 29035
33 8 52 6
3 0 204 2419368 185708 5046272 0 0 4 660 2735 24732
36 7 51 6
2 0 204 2419244 185712 5046296 0 0 0 360 2251 3193 9
1 84 5
3 0 204 2407096 185712 5046296 0 0 0 332 2319 3269 20
3 72 5

Erik Jones, Database Administrator
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