Re: Session locks up and will not die - maybe a MySQL bug
Re: Session locks up and will not die - maybe a MySQL bug
- Subject: Re: Session locks up and will not die - maybe a MySQL bug
- From: Marek Wawrzyczny <email@hidden>
- Date: Mon, 24 Nov 2003 09:53:31 +1100
The problem the email mentions does not appear to be purely MySQL.
While yes, the MySQL settings for concurrent users and open files were
low in his distribution, at the end of the article he says:
"It appeared that that the client process (which to this point had
been totally ignored) may be running out of file descriptors itself."
and
"This was fine for the MySQL server process, but for clients, it
was a disaster. While the pid for the server process was discrete,
clients could be any process. What we really needed to do was
alter the per process soft file descriptor limit."
Finally, the author of the email goes on to modify kernel source and
recompiles the kernel to fix his problem where his client application
is running out of file descriptors (not MySQL). The article suggests
that:
a) If MySQL is the problem, you should see "Too many files open"
messages in your MySQL logs.
b) If you are NOT seeing these messages in your MySQL logs, then there
is a problem purely with your WO application.
On Saturday, Nov 22, 2003, at 08:56 Australia/Sydney, Denis Stanton
wrote:
Hi Denis
thank you for a superb piece of detective work in finding this report
of a problem that may be the same as mine.
I have confirmed that I am using MySQL 4.0.14 on my server. What I
can't find is any evidence that the problem report you referred name
to has been recognized and fixed. The report you quoted was dated
over a year ago. I've tried searching the MySQL bug list for "too
many files" but I have not found anything that matches. I'm not very
familiar with this sort of bug tracking so if anybody has experience
of this I would appreciate the help.
The basic questions are:
1) Is it possible that MySQL 4.0.14 has a bug relating to file
descriptor limits that can cause a "too many open files" messages in
WebObjects 5.2.1?
For example:
[2003-11-21 12:00:37 NZDT] <WorkerThread138> <WOWorkerThread id=138
socket=null> IOException occurred while accepting server socket:
java.net.SocketException: Too many open files
In my case this message was repeated over and over, with varying
thread numbers, until WebObjects hung with a 635 MB log file full of
these messages.
2) Is it possible that MySQL people have fixed this since 4.0.14? The
latest build is 4.0.16. I could just install that, but I'd rather not
disrupt my users unless I have reason to believe that the upgrade will
actually help.
The report from Eric referred to maxusers being set too low at 32
In my standard MySQL set up I have:
max_user_connections = 0
open_files_limit = 0
Do you think I should change these? Zero is commonly used to mean
"unlimited"
I would not know how to apply the fix Eric came up with, or really to
determine whether it was required.
regards
Denis (Stanton)
On Saturday, November 22, 2003, at 07:21 AM,
email@hidden wrote:
Hi
On Friday, November 21, 2003, at 12:30 am, Denis Stanton wrote:
[2003-11-21 12:00:37 NZDT] <WorkerThread195> <WOWorkerThread id=195
socket=null> IOException occurred while accepting server socket:
java.net.SocketException: Too many open files
and so on for another 600+ MB.
Please can someone tell me what this means? Who has to many files?
I just use EOM to communicate with a MySQL database. It looks like
one file to me.
I'm using Mac OS X 10.2.8. WebObjects 5.2.1 and MySQL
MySQL is either 4.0.14 or 4.0.16, I'm not sure if I updated the
server/
My SQL connector is 3.0.1 or 3.0.9
You may need to upgrade MySQL. There was this problem:
http://mail-index.netbsd.org/netbsd-users/2002/09/02/0000.html
...Which is most likely fixed by now.
-- Denis.
Denis Stanton
email@hidden
Home: (09) 533 0391
mobile: 021 1433622
Denis Stanton
email@hidden
Home: (09) 533 0391
mobile: 021 1433622
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Marek Wawrzyczny
software engineer
-------------------------->
ish group pty ltd
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