28.5.1 Debugging a MySQL Server
- 18.104.22.168 Compiling MySQL for Debugging
- 22.214.171.124 Creating Trace Files
- 126.96.36.199 Using WER with PDB to create a Windows crashdump
- 188.8.131.52 Debugging mysqld under gdb
- 184.108.40.206 Using a Stack Trace
- 220.127.116.11 Using Server Logs to Find Causes of Errors in mysqld
- 18.104.22.168 Making a Test Case If You Experience Table Corruption
If you are using some functionality that is very new in MySQL, you can try to run mysqld with the
--skip-new option (which disables all new, potentially unsafe functionality). See Section B.4.3.3, “What to Do If MySQL Keeps Crashing”.
If mysqld does not want to start, verify that you have no
my.cnf files that interfere with your setup! You can check your
my.cnf arguments with mysqld --print-defaults and avoid using them by starting with mysqld --no-defaults ....
If mysqld starts to eat up CPU or memory or if it “hangs,” you can use mysqladmin processlist status to find out if someone is executing a query that takes a long time. It may be a good idea to run mysqladmin -i10 processlist status in some window if you are experiencing performance problems or problems when new clients cannot connect.
The command mysqladmin debug dumps some information about locks in use, used memory and query usage to the MySQL log file. This may help solve some problems. This command also provides some useful information even if you have not compiled MySQL for debugging!
If the problem is that some tables are getting slower and slower you should try to optimize the table with
OPTIMIZE TABLE or myisamchk. See Chapter 5, MySQL Server Administration. You should also check the slow queries with
You should also read the OS-specific section in this manual for problems that may be unique to your environment. See Section 2.1, “General Installation Guidance”.