Documentation > Debugging > Debugging C++ Execution Engine

Enabling Debug at Compilation

The EE debug log messages can only be enabled through recompilation. To rebuild the entire EE, execute the following command:

ant clean-cpp build -Dbuild=debug -Dsite.exec_ee_log_level=INFO

The site.exec_ee_log_level parameter sets the level of output information generated by the EE.

Debugging Execution Engine in GDB

1. Start the system in another terminal and use the following command to get the process id of the HStoreSite’s JVM:

   ps aux | grep hstore.tag=site | grep -v grep | awk '{print $2}'

2. Attach gdb to the running process. Make sure you pass in the debug symbols that are generated at compilation time:

   sudo gdb --symbols=obj/release/nativelibs/libvoltdb.sym --pid=7103

3. Now at the gdb prompt, you can set a breakpoint for the part of the Execution Engine that you want to debug. For example, the following command will allow you to set a breakpoint at line 186 for the file persistenttable.cpp

   (gdb) break "persistenttable.cpp:186"