On 31-Mar-2003 Mike William wrote:
> After a routine restart of our MySQL 3.23 server today, we began getting
> the following PHP error message during times of moderately high database
> server load:
>
> Warning: MySQL Connection Failed: Can't create a new thread (errno 11).
> If
> you are not out of
> available memory, you can consult the manual for a possible OS-dependent
> bug in
> /www/data/functions/common/auth.inc on line 33
>
> Line 33 of the that file is a call to mysql_pconnect(). However, if I
> comment out that line temporarily, the error message simply moves to
> another line in another file that is also a call to mysql_pconnect(). If
> I
> comment out all of my mysql_pconnect()'s then the error goes away,
> although
> obviously this breaks my entire website.
>
> I am definitely not out of memory. top says:
>
> 02:38:23 up 45 days, 9:23, 3 users, load average: 0.04, 0.13, 0.16
> 211 processes: 208 sleeping, 1 running, 2 zombie, 0 stopped
> CPU states: 18.5% user, 3.6% system, 0.0% nice, 77.9% idle
> Mem: 2069204K total, 1724224K used, 344980K free, 52840K buffers
> Swap: 0K total, 0K used, 0K free, 1486132K cached
>
> Also, the maximum number of OS threads set in my kernel is 14336. I
> can't
> see any evidence that MySQL is trying to exceed this value (see the
> thread
> status variables I pasted below).
>
> On a possibly related note, I have discovered the following fact. If I
> restart MySQL, the error message goes away temporarily. Then, as my site
> runs for a while, the number of open persistent connections to the
> database
> slowly increases from 0 up to 250. When it hits 250 or 251, the error
> message suddenly returns. I do not understand the significance of the
> number 250, although I have noticed that when I run a SHOW STATUS, the
> value of max_used_connections rises from an initial value of 0 (when the
> server starts) up to 251 (at which point the error message starts), and
> furthermore this rise takes place at about the same rate as the rise in
> the
> number of persistent connections. I don't know whether this is important
> or not, although I am intrigued by the fact that this problem only
> happens
> when max_used_connections and the number of open persistent connections
> hits the 251 "ceiling."
>
> Here are some select variables from SHOW STATUS as they appear once the
> server hits the wall and starts giving off this error message:
>
>| Max_used_connections | 251 |
>| Connections | 60980 |
>| Threads_cached | 5 |
>| Threads_created | 4303 |
>| Threads_connected | 86 |
>| Threads_running | 1 |
>
> If anyone has any ideas, please let me know. Thanks!
>
Your pconnects are probably sleeping too long.
in /etc/my.cnf:
[mysqld]
set-variable = wait_timeout=10
That'll get the connections to die off after 10 seconds.
If that doesn't take care of it, check your PHP version. Early (~ 2001)
PHP4 had some buggy pconnect problems.
Last resort:
Don't use pconnect unless you really --and I mean *really* need it.
mysql_connect() is fast enough for just about everything.
Regards,
--
Don Read [EMAIL PROTECTED]
-- It's always darkest before the dawn. So if you are going to
steal the neighbor's newspaper, that's the time to do it.
(53kr33t w0rdz: sql table query)
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