On some operating systems, the error log contains a stack
trace if mysqld dies unexpectedly. You can
use this to find out where (and maybe why)
mysqld died. See
Section 5.4.1, “The Error Log”. To get a stack trace, you must
not compile mysqld with the
-fomit-frame-pointer option to gcc. See
Section 188.8.131.52, “Compiling MySQL for Debugging”.
A stack trace in the error log looks something like this:
mysqld got signal 11; Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack range sanity check, ok, backtrace follows 0x40077552 0x81281a0 0x8128f47 0x8127be0 0x8127995 0x8104947 0x80ff28f 0x810131b 0x80ee4bc 0x80c3c91 0x80c6b43 0x80c1fd9 0x80c1686
Copy the preceding numbers to a file, for example
0x9da402 0x6648e9 0x7f1a5af000f0 0x7f1a5a10f0f2 0x7412cb 0x688354 0x688494 0x67a170 0x67f0ad 0x67fdf8 0x6811b6 0x66e05e
Make a symbol file for the mysqld server:
nm -n libexec/mysqld > /tmp/mysqld.sym
If mysqld is not linked statically, use the following command instead:
nm -D -n libexec/mysqld > /tmp/mysqld.sym
If you want to decode C++ symbols, use the
--demangle, if available, to nm. If your version of nm does not have this option, you will need to use the c++filt command after the stack dump has been produced to demangle the C++ names.
Execute the following command:
resolve_stack_dump -s /tmp/mysqld.sym -n mysqld.stack
If you were not able to include demangled C++ names in your symbol file, process the resolve_stack_dump output using c++filt:
resolve_stack_dump -s /tmp/mysqld.sym -n mysqld.stack | c++filt
However, in most cases it does not help us to have just a stack trace to find the reason for the problem. To be able to locate the bug or provide a workaround, in most cases we need to know the statement that killed mysqld and preferably a test case so that we can repeat the problem! See Section 1.7, “How to Report Bugs or Problems”.