Using libcoredumper¶
A core dump file is the documented moment of a computer when either the computer or an application exits. Developers examine the dump as one of the tasks when searching for the cause of a failure.
The libcoredumper is a free and Open Source fork of google-coredumper,
enhanced to work on newer Linux versions, and GCC and CLANG.
Enabling the libcoredumper¶
Enable core dumps for troubleshooting purposes.
To enable the libcoredumper, add the coredumper variable to the
mysqld section of my.cnf. This variable is independent of the
older core-file variable.
The variable can have the following possible values:
| Value | Description |
|---|---|
| Blank | The core dump is saved under MySQL datadir and named core. |
| A path ending with / | The core dump is saved under the specified directory and named core. |
| Full path with a filename | The core dump is saved under the specified directory and filename |
Restart the server.
Verifying the libcoredumper is active¶
MySQL writes to the log when generating a core file and delegates the core dump operation to the Linux kernel.
Writing a core file
MySQL using the libcoredumper to generate the file creates the following
message in the log:
Writing a core file using lib coredumper
Every core file adds a crash timestamp instead of a PID for the following reasons:
- Correlates the core file with the crash. MySQL prints a UTC timestamp on the crash log.
10:02:09 UTC - mysqld got signal 11;
- Stores multiple core files.
Note
For example, operators and containers run as the process id of PID 1. If the process ID is used to identify the core file, each container crash generates a core dump that overwrites the previous core file.
Disabling the libcoredumper¶
You can disable the libcoredumper. A core file may contain sensitive data and takes disk space.
To disable the libcoredumper you must do the following:
-
In the
mysqldsection of my.cnf, remove thelibcoredumpervariable. -
Restart the server.
Get expert help¶
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