If you are using some functionality that is very new in MySQL,
you can try to run mysqld with the
--skip-new (which disables all new, potentially
unsafe functionality) or with
--safe-mode which disables a lot
of optimization that may cause problems. See
Section B.5.4.2, “What to Do If MySQL Keeps Crashing”.
If mysqld doesn't want to start, you should
verify that you don't have any
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 can't 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 haven't 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
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 2.12, “Operating System-Specific Notes”.