Thanks for the reply. It helped alot, since I did not know where to look.
I read the documentation regarding the issue and some more pages google
turned up for me.
I did increase my table cache to 16k and my open files are at 30k. I do
run debian etch 32-bit. How would I determine what reasonable means for
open files are on my system? I have 4GB Ram and a 2.6 Ghz DualCore.
What also interests me is my key buffer. I have it set to 768MB:
mysql> show status like "key%";
+------------------------+----------+
| Variable_name | Value |
+------------------------+----------+
| Key_blocks_not_flushed | 0 |
| Key_blocks_unused | 661370 |
| Key_blocks_used | 40169 |
| Key_read_requests | 22935142 |
| Key_reads | 65152 |
| Key_write_requests | 1941899 |
| Key_writes | 162770 |
+------------------------+----------+
7 rows in set (0.00 sec)
This would mean the following:
65152 Key_reads / 22935142 Key_read_requests * 100 = 0.29 %
I think this would be an reasonable value. Am I right?
Regards,
Samy
Brent Baisley schrieb:
The problem is your table cache setting. MySQL will only keep a
certain amount of tables open and ready for access. Once that limit is
hit, if a table that is not already open needs to be accessed, it
needs to close a table to make room for opening the "new" table.
This doesn't mean you can just set the table cache size really high.
The operating system has limits as to how many file handles it can
have open at one time.
In mysql type this:
show status like "open%"
Your Opened_tables number is probably huge. That's how many times
mysql had to open a table for access. Meaning the table wasn't opened
already. The Open_tables is how many tables MySQL will keep open
(table cache). You need to increase this number using the table_cache
variable.
set global table_cache=#;
The Open_files number from the show status command is important, make
sure that stays within limits of your operating system.
On Nov 12, 2007 5:09 PM, Samuel Vogel <[EMAIL PROTECTED]> wrote:
Hey guys,
I do run MySQL on a high traffic Server with approximately 10k
databases. Since some time MySQL is has become very sluggish.
When I look at my processlist it shows more than 25 processes (sometimes
of the same & table) with status "Opening tables". Some processes also
show "closing tables".
Since I am running I shared hosting environment, I can not examine the
situation to such extent, where I could see if table locks are
involved. But it does not seem to be the case, since it does not appear
for just some users, but for everybody. Also when I run a simple select
query it takes more than 2 sec.
I guess MySQL is trying to tell me, that my hard drive is too slow. How
could I ease this situation ?
My key_buffer is set to 1Gb of my 4Gb system memory. Other values are
tweaked as well, but I do not think the matter in that case.
Would partitioning the disk as Raid 0 ease the situation?
What other places do I have to look at, to further narrow down the problem?
Regards,
Samy
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
