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Re: sudden spurt in swap utilization (was:cpu bound postgresql setup.)

From: Rajesh Kumar Mallah <mallah(dot)rajesh(at)gmail(dot)com>
To: Kevin Grittner <Kevin(dot)Grittner(at)wicourts(dot)gov>
Cc: Yeb Havinga <yebhavinga(at)gmail(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: sudden spurt in swap utilization (was:cpu bound postgresql setup.)
Date: 2010-06-25 15:14:41
Message-ID: AANLkTimPhkr2nvuLo-fpBfUdN08KsDFTwzL9ubJP5VG2@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
I changed shared_buffers from 10G to 4G ,
swap usage has almost become nil.

# free
             total       used       free     shared    buffers     cached
Mem:      32871276   24575824    8295452          0      11064   22167324
-/+ buffers/cache:    2397436   30473840
Swap:      4192912        352    4192560

I also observed that there was a huge IO wait and load spike initially
which gradually reduced to normal levels. Now things seems to be
fine. but real test shall be during business hours.

vmstat output:
http://pastebin.com/ygu8gUhS

the iowait now is very respectable < 10% and CPU is idling most of
the time.

# vmstat 10
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 2  1    352 8482444  11336 22299100    1    0   450   208    0    0
50  6 39  5  0
 4  0    352 8393840  11352 22304484    0    0   480   163 9260 12717
32  4 62  3  0
 5  1    352 8474788  11360 22308980    0    0   304   445 8295 12358
28  4 67  2  0
 3  0    352 8370672  11376 22316676    0    0   648   158 8760 13214
38  4 55  3  0
11  0    352 8193824  11392 22323572    0    0   621   577 8800 13163
37  4 56  3  0
 2  0    352 8229012  11408 22326664    0    0   169   405 9588 13696
34  4 61  1  0
 6  1    352 8319176  11424 22333144    0    0   559   170 8830 12929
32  4 61  3  0

I shall also try pgtune in a while.

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Next:From: Rajesh Kumar MallahDate: 2010-06-25 15:59:21
Subject: Re: sudden spurt in swap utilization (was:cpu bound postgresql setup.)
Previous:From: Tom LaneDate: 2010-06-25 14:47:10
Subject: Re: Occasional giant spikes in CPU load

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