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A.1. How to Determine What Is Causing a Problem
When you run into a problem, the first thing you should do is to
find out which program or piece of equipment is causing it:
-
If you have one of the following symptoms, then it is probably
a hardware problems (such as memory, motherboard, CPU, or hard
disk) or kernel problem:
The keyboard doesn't work. This can normally be checked by
pressing the Caps Lock key. If the Caps Lock light doesn't
change, you have to replace your keyboard. (Before doing
this, you should try to restart your computer and check
all cables to the keyboard.)
The mouse pointer doesn't move.
The machine doesn't answer to a remote machine's pings.
Other programs that are not related to MySQL don't behave
correctly.
Your system restarted unexpectedly. (A faulty user-level
program should never be able to take down your system.)
In this case, you should start by checking all your cables and
run some diagnostic tool to check your hardware! You should
also check whether there are any patches, updates, or service
packs for your operating system that could likely solve your
problem. Check also that all your libraries (such as
glibc) are up to date.
It's always good to use a machine with ECC memory to discover
memory problems early.
If your keyboard is locked up, you may be able to recover by
logging in to your machine from another machine and executing
kbd_mode -a.
Please examine your system log file
(/var/log/messages or similar) for
reasons for your problem. If you think the problem is in
MySQL, you should also examine MySQL's log files. See
Section 5.11, “MySQL Server Logs”.
If you don't think you have hardware problems, you should try
to find out which program is causing problems. Try using
top, ps, Task Manager,
or some similar program, to check which program is taking all
CPU or is locking the machine.
Use top, df, or a
similar program to check whether you are out of memory, disk
space, file descriptors, or some other critical resource.
If the problem is some runaway process, you can always try to
kill it. If it doesn't want to die, there is probably a bug in
the operating system.
If after you have examined all other possibilities and you have
concluded that the MySQL server or a MySQL client is causing the
problem, it's time to create a bug report for our mailing list or
our support team. In the bug report, try to give a very detailed
description of how the system is behaving and what you think is
happening. You should also state why you think that MySQL is
causing the problem. Take into consideration all the situations in
this chapter. State any problems exactly how they appear when you
examine your system. Use the “copy and paste” method
for any output and error messages from programs and log files.
Try to describe in detail which program is not working and all
symptoms you see. We have in the past received many bug reports
that state only “the system doesn't work.” This
doesn't provide us with any information about what could be the
problem.
If a program fails, it's always useful to know the following
information:
Has the program in question made a segmentation fault (did it
dump core)?
Is the program taking up all available CPU time? Check with
top. Let the program run for a while, it
may simply be evaluating something computationally intensive.
If the mysqld server is causing problems,
can you get any response from it with mysqladmin -u
root ping or mysqladmin -u root
processlist?
What does a client program say when you try to connect to the
MySQL server? (Try with mysql, for
example.) Does the client jam? Do you get any output from the
program?
When sending a bug report, you should follow the outline described
in Section 1.8, “How to Report Bugs or Problems”.
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