CentOS - Nov 2009 - MySQL error 28, can't write temp files - how to debug?

Hi all,

I hope someone can help with this one.

On one of our VPS's we have a fairly large MySQL database, which gives
me the following error when running some queries against it:



An error occured!Can't execute statement: Error writing file
'/tmp/MYL4qeT5' (Errcode: 28)
SQL: , , select * from tips order by rand() limit 0, 1 ,



According to google search, errorcode 28 means the HDD is full. But it
isn't:


root at vps:[~]$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              84G   18G   62G  23% /
none                  640M     0  640M   0% /dev/shm
/usr/tmpDSK           485M   11M  449M   3% /tmp


What else could cause this kind of problem?

-- 
Kind Regards
Rudi Ahlers
CEO, SoftDux Hosting
Web: http://www.SoftDux.com
Office: 087 805 9573
Cell: 082 554 7532

On Thursday 05 November 2009, Rudi Ahlers <Rudi at softdux.com>
wrote:
> According to google search, errorcode 28 means the HDD is full. But it
> isn't:
>
>
> root at vps:[~]$ df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/sda1              84G   18G   62G  23% /
> none                  640M     0  640M   0% /dev/shm
> /usr/tmpDSK           485M   11M  449M   3% /tmp
>
>
> What else could cause this kind of problem?
You only have 449MB free on /tmp. It could easily fill that up during the 
query, and then delete the file before you run df again. Run it while the 
query is executing, I bet you see /tmp filling up.

-- 
"No animals were harmed in the recording of this episode. We tried but that
damn monkey was just too fast."

On Thu, Nov 5, 2009 at 11:44 PM, Rudi Ahlers <Rudi at softdux.com> wrote:
> Hi all,
>
> An error occured!Can't execute statement: Error writing file
> '/tmp/MYL4qeT5' (Errcode: 28)
> SQL: , , select * from tips order by rand() limit 0, 1 ,
>
check if you have enough free inodes with df -i
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