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Jeff Denny - mysql connection problem

Jeff Denny - mysql connection problem

by Arnold Pizer -
Number of replies: 0
inactiveTopicmysql connection problem topic started 8/29/2005; 7:00:52 PM
last post 8/31/2005; 2:49:08 PM
userJeff Denny - mysql connection problem  blueArrow
8/29/2005; 7:00:52 PM (reads: 546, responses: 4)
Suddenly, I'm getting the following error when trying to log into any of my courses. I cannot even get the login page to come up.

Any ideas?

To see the error, go to http://mathww.mercer.edu/webwork2/mat192denny/

----

error instantiating DB driver WeBWorK::DB::Driver::SQL for table problem_user: DBI connect('webwork','webworkRead',...) failed: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111) at /opt/webwork2/lib/WeBWorK/DB/Driver/SQL.pm line 62 at /opt/webwork2/lib/WeBWorK.pm line 211

Call stack

The information below can help locate the source of the problem. in Carp::croak called at line 221 of /opt/webwork2/lib/WeBWorK/DB.pm in WeBWorK::DB::new called at line 211 of /opt/webwork2/lib/WeBWorK.pm

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userMichael Gage - Re: mysql connection problem  blueArrow
8/29/2005; 7:20:35 PM (reads: 598, responses: 0)
To troubleshoot:

See if you can access the mysql database directly using John's directions at

http://webhost.math.rochester.edu/webworkdocs/discuss/msgReader$3643#3646

We've seen this error twice today on this list. My guess is that the problem has to do with the connection with the mysql database. The password is wrong, the webworkWrite name in the database is wrong, perhaps the database server has stopped running? However if you can connect directly to the database using webworkWrite and the password then something else is wrong. Perhaps some recent change in one of the WeBWorK scripts.

Report back and let us know how things work out.

-- Mike

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userJeff Denny - Re: mysql connection problem  blueArrow
8/30/2005; 9:40:10 AM (reads: 604, responses: 1)
mysql apparently went down yesterday. I did a hard reboot and mysql did not restart for some reason. So, our sys admin restarted mysql manually this morning, and all is well now...I think.

The postmortem from our sys admin is that sql ran out of memory at 5:30pm and died. Then our web processes starting dying. The sys admin thinks we may have a memory leak or a hardware problem with memory. He's going to look for evidence of memory not being returned to the stack properly.

Thank you for your help!

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userJohn Curran - Re: mysql connection problem  blueArrow
8/31/2005; 10:18:15 AM (reads: 666, responses: 0)
Did your sys admin say how to detect whether sql is run out of memory? I am getting a similar message to yours but restarting mysql hasn't made a difference in our case.

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userJeff Denny - Re: mysql connection problem  blueArrow
8/31/2005; 2:49:08 PM (reads: 575, responses: 0)
John,

Our system had run out of memory, so oomkiller (Red Hat Linux) starting killing processes. We found evidence of the memory problem in the system logs that showed what oomkiller had done. I don't know if this helps. Our sys admin also says that running top might give you helpful info.

Jeff

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