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From:Michael Widenius Date:October 14 1999 1:58am
Subject:problems on Solaris: slow speed or stop
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>>>>> "Juri" == Juri Kaljundi <jk@stripped> writes:

Juri> We are having problems with mysql when we switched from Redhat Linux to
Juri> Solaris 7 Intel (due to better SMP support on Solaris). The mysql seems a
Juri> little bit slower on Solaris, but the real problem is that under high low
Juri> the mysql process starts to take 95% of CPU and at that moment it just
Juri> freezes. mysql.server stop does not kill the process, it just stays
Juri> hovering there at 85-95% even when nobody is accessing it anymore. 

Juri> When the mysql goes slow, mysqladmin pro sometimes shows quite a lot of
Juri> state locked, probably for updates being done. 

Juri> truss on mysql process shows just thousands of lines per second like: 
Juri> llseek(35, 453423, SEEK_SET)                    = 453423
Juri> read(35, "030F\00F\001 C03\0\015", 11)          = 11
Juri> llseek(35, 453428, SEEK_SET)                    = 453428
Juri> read(35, "01 C03\0\015\0\0\0\0\0\0".., 15)      = 15
Juri> llseek(35, 453443, SEEK_SET)                    = 453443
Juri> read(35, "030F\00F\001 B03\0\017", 11)          = 11

The above means that MySQL is doing table scanning on a dynamic-row table.

Juri> Solaris 7 Intel x86, gcc 2.95.1, mysql 3.22.26 or 3.22.27. mysql accessed
Juri> over perl or php. Tables are small, probably not over 10-20 thousand
Juri> records each. Worked quite OK on Linux on even slower machine. 

Juri> CXXFLAGS were like  -O6 -fomit-frame-pointer -felide-constructors
Juri> -fno-exceptions -fno-rtti  -fno-implicit-templates 

Juri> What to explore? Where to look?

Juri> Juri Kaljundi
Juri> jk@stripped                     Mustamae tee 55, Tallinn 10621, Estonia
Juri> AS Stallion                        Tel: +372-656 7720
Juri>            Fax: +372-656 7727


Some suggestions:

If you can mail the output from 'mysqladmin proc ext var' ; We may be
able to give you some suggestions.

Have you tried '/usr/proc/bin/pstack' when MySQL goes slow/dies.  This 
may help find out what MySQL is doing!

problems on Solaris: slow speed or stopJuri Kaljundi13 Oct
  • Re: problems on Solaris: slow speed or stopsinisa13 Oct
  • problems on Solaris: slow speed or stopMichael Widenius14 Oct
  • Re: problems on Solaris: slow speed or stopTonu Samuel14 Oct