Compiling MariaDB for Debugging
- Compiling MariaDB for Debugging Using the CMAKE_BUILD_TYPE Option
- Compiling MariaDB for Debugging Using Build Scripts
- Building Optimized Build With Debug Symbols
- Doing a Debug Build on Debian/Ubuntu
- Different Compilation Options
- See Also
Compiling MariaDB with full debug information includes all code symbols and also new code to do internal testing of structures and allow one to trace MariaDB execution. A full debug binary will be notably slower than a normal binary (30%).
Compiling MariaDB for Debugging Using the
On Unix systems, you can build a debug build by executing
cmake and by setting the
CMAKE_BUILD_TYPE option to
Debug. For example:
cmake -DCMAKE_BUILD_TYPE=Debug .
Compiling MariaDB for Debugging Using Build Scripts
The other option is to use the scripts in the BUILD directory that will compile MariaDB with most common debug options and plugins:
There are separate build scripts for different configurations in the BUILD directory.
You can find a list of the needed packages/libraries for building on Linux here.
Example of Compiling MariaDB for Debugging Using Build Scripts
- Scripts containing "debug" in the name are for developers that want to build, develop and test MariaDB.
- Scripts containing "valgrind" in the name are for running mysqld under [[|http://valgrind.org|valgrind]]. Compiling for valgrind means that we are using another implementation of MEM_ROOT to allow valgrind to better detect memory overruns. In addition, some memory areas are marked as used/not used to remove some false positives.
- Scripts containing "max" in the name include all normal plugins.
Here is an example of how to compile MariaDB for debugging in your home directory with MariaDB 5.2.9 as an example:
cd ~ mkdir mariadb cd mariadb tar xvf mariadb-5.2.9.tar.gz ln -s mariadb-5.2.9 current cd current ./BUILD/compile-pentium64-debug-max
The last command will produce a debug version of
If you have a system other than 64 bit Intel/AMD on Linux you can use a
BUILD/...-debug-max file. If this fails, you can
cmake --build . --config Debug make -j4
Building Optimized Build With Debug Symbols
To build MariaDB with symbols, to get better stack traces and to be able to debug the binary with
gdb, you need to supply the
-g3 option to the
Just compiling with
-g3 will make the binary much bigger but the slowdown of the server should be negligible.
One way to do this is to edit the script
and add the -g3 last on the line with
extra_flags, like this:
extra_flags="$pentium64_cflags $fast_cflags -g3"
After that you can compile MariaDB with debugging symbols by just execution the above script.
Doing a Debug Build on Debian/Ubuntu
To build a "mysqld" binary with debugging enabled that uses the same parameters as the ones used in Debian/Ubuntu binary packages, you must do as follows (you must have a deb-src line of one of the MariaDB repositories on your /etc/apt/sources.list in order to do that):
apt-get build-dep mariadb-10.2 apt-get install cmake libaio1 libaio-dev apt-get source mariadb-10.2 cd mariadb-10.2* ./debian/rules configure ./BUILD/compile-pentuim64-debug-all
Then you will have your "debugging enabled" mysqld binary in the sql/ directory.
This binary can directly replace the one provided by the binary package that is placed on "/usr/bin/mysqld".
Different Compilation Options
Changing DBUG_ASSERT to Print to Error Log
A debug binary has lots of code checks and asserts, that are not checked in production. This is done to get more performance when running in production. In some cases, when one is trying to find a hard-to-repeat bug, it could be beneficial to have these checks in production builds too.
-DDBUG_ASSERT_AS_PRINTF will change DBUG_ASSERT() to print any failed check to the error log.
cmake . -DDBUG_ASSERT_AS_PRINTF
Enabling the above option should not have any notable impact on performance (probably < 1% slowdown). This is achieved by grouping asserts in MariaDB server code into two groups:
- Fast checks, using
DBUG_ASSERT(): These are converted to printing to error log.
- Slow checks, using
DBUG_SLOW_ASSERT(). These will always be removed in production builds.