MYSQL performance

Anon

i'm using php 4.0.4pl1 and mysql 3.23.38 on my site

To test MYSQL performance i made a PHP script to record how much time each sql query proccesed by MySQL

I was wondering why the same sql query takes different time to complete.

Typically the time was about 0,001 seconds but two times the time was 10 seconds!!!!

Any one knows the reason???

[deleted]

For the same reason that it sometimes takes you longer to get to work.
Sometimes the server is busy doing something else, sometimes it's waiting for you to get a move on.

The two 10 second runs are strange. Are you running the script through a webserver?

al77_t

Are you running the script through a webserver?

Yes... Linux+Apache 1.3.19 on cobalt RAQ4

al77_t

Here is whta the "Top" command at linux return to me... May be this will be useful..

12:24pm up 1 day, 22:22, 5 users, load average: 1.26, 1.64, 1.89
90 processes: 87 sleeping, 3 running, 0 zombie, 0 stopped
CPU states: 0.7% user, 3.1% system, 0.0% nice, 96.1% idle
Mem: 128040K av, 124836K used, 3204K free, 38508K shrd, 3128K buff
Swap: 131532K av, 25236K used, 106296K free 31192K cached

PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME COMMAND
3261 root 13 0 912 912 668 R 0 2.9 0.7 0:12 top
31429 www 1 0 4524 2652 1212 S 0 0.1 2.0 0:04 httpd
19164 www 1 0 4884 2776 1480 S 0 0.1 2.1 0:01 httpd
1 root 0 0 120 68 48 S 0 0.0 0.0 0:06 init
2 root 0 0 0 0 0 SW 0 0.0 0.0 0:02 kflushd
3 root 0 0 0 0 0 SW 0 0.0 0.0 0:10 kupdate
4 root 0 0 0 0 0 SW 0 0.0 0.0 0:00 kpiod
5 root 0 0 0 0 0 SW 0 0.0 0.0 0:13 kswapd
6 root -20 -20 0 0 0 SW< 0 0.0 0.0 0:00 mdrecoveryd
325 root 0 0 216 160 116 S 0 0.0 0.1 0:04 syslogd
334 root 0 0 116 60 36 S 0 0.0 0.0 0:02 inetd
405 root 0 0 1512 1100 524 S 0 0.0 0.8 0:32 named
416 root 0 0 3736 52 32 S 0 0.0 0.0 0:04 httpd
446 root 0 0 676 392 284 S 0 0.0 0.3 0:02 sendmail
470 root 0 0 40 40 24 S 0 0.0 0.0 0:00 lcdsleep
509 root 0 0 152 0 0 SW 0 0.0 0.0 0:00 safe_mysqld
511 root 0 0 76 0 0 SW 0 0.0 0.0 0:00 getty
530 root 5 5 9460 6628 1144 S N 0 0.0 5.1 0:02 mysqld
545 root 10 5 9460 6628 1144 S N 0 0.0 5.1 0:03 mysqld
546 root 5 5 9460 6628 1144 S N 0 0.0 5.1 0:00 mysqld
589 root 0 0 2544 264 220 S 0 0.0 0.2 0:00 httpd
630 root 0 0 816 0 0 SW 0 0.0 0.0 0:00 perl
632 root 0 0 144 0 0 SW 0 0.0 0.0 0:00 sh
633 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:04 java
704 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:00 java
705 root 0 0 57972 53M 4200 S 0 0.0 42.5 1:26 java
706 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:01 java
707 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:03 java
728 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:03 java
729 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:00 java
730 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:05 java
734 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:00 java
735 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:01 java
758 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:00 java
759 root 0 0 57972 53M 4200 S 0 0.0 42.5 0:00 java
870 root 0 0 57972 53M 4200 S 0 0.0 42.5 6:00 java
896 root 0 0 57972 53M 4200 S 0 0.0 42.5 6:39 java

kparker

It's useful insofar as it shows a lightly-loaded server. Your problem could just as well have been network congestion between you and the server, a router that somebody rebooted, etc. But I agree with Vincent, 2 separate 10-second runs seems odd.