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Repair table - CPU remains idle
Posted by: Vijay Patel
Date: February 08, 2005 02:49AM

Hello,

While i am giving repair table command from mysql prompt, it is taking too much time for repairing.

1) While monitoring processes from "top"
it shows 97% CPU time idle.
--------Output of top---------
last pid: 4464; load averages: 0.12, 0.08, 0.02 up 1+04:08:48 00:40:08
41 processes: 1 running, 40 sleeping
CPU states: 0.0% user, 0.0% nice, 1.9% system, 0.4% interrupt, 97.7% idle
Mem: 403M Active, 1341M Inact, 152M Wired, 95M Cache, 112M Buf, 3260K Free
Swap: 4053M Total, 88K Used, 4053M Free

PID USERNAME PRI NICE SIZE RES STATE TIME WCPU CPU COMMAND
4050 mysql -4 14 423M 389M getblk 13:24 2.39% 2.39% mysqld
372 root 96 0 3440K 2232K select 0:01 0.00% 0.00% sendmail
4052 mysql 20 14 423M 389M pause 0:01 0.00% 0.00% mysqld
388 root 8 0 1356K 900K nanslp 0:00 0.00% 0.00% cron
255 root 96 0 1312K 784K select 0:00 0.00% 0.00% syslogd
330 root 96 0 1236K 688K select 0:00 0.00% 0.00% usbd
4026 mysql 107 11 423M 389M select 0:00 0.00% 0.00% mysqld
4027 mysql 107 11 423M 389M select 0:00 0.00% 0.00% mysqld
4461 root 96 0 2324K 1472K RUN 0:00 0.00% 0.00% top
4313 vijay 96 0 6092K 2372K select 0:00 0.00% 0.00% sshd
4084 vijay 96 0 6092K 2296K select 0:00 0.00% 0.00% sshd
376 smmsp 20 0 3340K 1988K pause 0:00 0.00% 0.00% sendmail
4316 root 20 0 2224K 1572K pause 0:00 0.00% 0.00% csh
4087 root 5 0 2228K 1584K ttyin 0:00 0.00% 0.00% csh
4028 mysql 20 11 423M 389M pause 0:00 0.00% 0.00% mysqld
4049 root 4 0 3300K 1808K sbwait 0:00 0.00% 0.00% mysql
3906 vijay 96 0 6092K 2288K select 0:00 0.00% 0.00% sshd
3903 root 4 0 6112K 2248K sbwait 0:00 0.00% 0.00% sshd
4310 root 4 0 6112K 2344K sbwait 0:00 0.00% 0.00% sshd
4081 root 4 0 6112K 2252K sbwait 0:00 0.00% 0.00% sshd
3909 root 20 0 2224K 1504K pause 0:00 0.00% 0.00% csh
4051 mysql 20 14 423M 389M pause 0:00 0.00% 0.00% mysqld
-------------


2) iostat -c 20 command shows heavy usage on disk.
----------------output of iostat--------
# iostat -c 20
tty ad4 cpu
tin tout KB/t tps MB/s us ni sy in id
0 4 18.22 146 2.61 0 2 3 1 94
0 128 17.29 259 4.37 0 4 3 1 92
0 43 18.90 256 4.73 0 2 5 3 90
0 43 16.79 259 4.25 0 4 4 1 92
0 43 17.09 261 4.36 0 2 6 1 91
0 43 17.36 233 3.94 0 4 2 2 93
0 43 17.23 246 4.13 0 2 4 1 93
0 43 17.08 263 4.39 0 5 3 2 90
0 43 17.49 245 4.18 0 2 2 1 95
0 43 17.49 266 4.55 0 3 2 2 94
0 43 17.43 254 4.33 0 5 4 1 91
0 43 17.99 255 4.47 0 1 4 2 93
0 43 18.26 259 4.63 0 5 3 2 89
0 43 17.97 257 4.52 0 5 3 1 91
0 43 17.41 258 4.39 0 4 2 1 93
0 43 18.18 247 4.38 0 3 4 1 92
0 43 17.12 241 4.02 0 1 4 1 95
0 43 17.74 246 4.25 0 2 6 2 89
0 43 19.32 267 5.04 0 1 5 2 92
0 43 17.91 265 4.64 0 5 4 1 90
---------------------------------


3) Server is having 2GB RAM & my.cnf is same as my-huge.cnf.
While before giving repair table, i changed these 2 variables...

set myisam_sort_buffer_size=512*1024*1024; (Prev: it was 64MB)
set read_buffer_size=10*1024*1024; (Prev: it ws 2MB)


4) my repair table command was like...
mysql> repair table data QUICK;

But it has not created any temp. table with "#" & pid.

# ls -l mydb/data.* #*
-rw-rw---- 1 mysql mysql 1453125264 Feb 7 21:25 mydb/data.MYD
-rw-rw---- 1 mysql mysql 1491445760 Feb 8 00:46 mydb/data.MYI
-rw-rw---- 1 mysql mysql 8578 Jan 28 05:29 mydb/data.frm

What is the reason for 97% Idle for CPU time. Is the system not configured properly?

Thank you,
Vijay.

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Repair table - CPU remains idle
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February 08, 2005 02:49AM
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