Re: [GENERAL] Upgrade to dual processor machine? - Mailing list pgsql-performance

From Shridhar Daithankar
Subject Re: [GENERAL] Upgrade to dual processor machine?
Date
Msg-id 3DD3C819.3038.3E3812E@localhost
Whole thread Raw
List pgsql-performance
On 14 Nov 2002 at 11:03, Henrik Steffen wrote:
> vmstat 1 5:
>    procs                      memory    swap          io     system         cpu
>  r  b  w   swpd   free   buff  cache  si  so    bi    bo   in    cs  us  sy  id
>  1  8  1     60   4964   5888 309684   0   0   176    74   16    32  25   9  66
>  0  6  3     60   4964   5932 308772   0   0  6264   256  347   347  13   9  78
>  0  5  1     60   4964   5900 309364   0   0  9312   224  380   309  11   6  83
>  1  4  1     60   5272   5940 309152   0   0 10320   116  397   429  17   6  77
>  1  4  1     60   4964   5896 309512   0   0 11020   152  451   456  14  10  76
> w:
> 12:04pm  up 2 days, 17:44,  1 user,  load average: 10.28, 7.22, 3.88
> USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU  WHAT
> root     pts/0    condor.city-map. 11:46am  0.00s  0.09s  0.01s  w
> this is when things begin to go more slowly....

Two things immediately noticable.. Load average and block ins..

Either your disk write BW is saturated or CPU is too full, which I believe is
the case. HAve you ever got faster write performance than 12K blocks say? Disk
BW may be a bottleneck here.. Are they IDE disks?

Besides almost transactions are insert/update.. And if you have 11K blocks per
second to write.. I suggest you vacuum analyse most used table one in a minute
or so. Decide the best frequency by trial and error. A good start is double the

time it takes for vacuum. i.e. if vacuum analyse takes 60 sec to finish, leave
a gap of 120 sec. between two runs of vacuum.

You need to vacuum only those tables which are heavily updated. This will make
vacuum faster.

HTH
Bye
 Shridhar

--
Nouvelle cuisine, n.:    French for "not enough food".Continental breakfast, n.:
English for "not enough food".Tapas, n.:    Spanish for "not enough food".Dim Sum,

n.:    Chinese for more food than you've ever seen in your entire life.


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