MySQL Source-Configuration Options • -DWITH_BOOST= path_name • -DWITH_BOOST= path_name  specifies the Boost library directory location. It is also possible to specify the Boost location by setting the  BOOST_ROOT  or  WITH_BOOST  environment variable. • -DDOWNLOAD_BOOST= bool  specifies whether to download the Boost source if it is not present in the specified location. The default is  OFF . • -DDOWNLOAD_BOOST_TIMEOUT= seconds  the timeout in seconds for downloading the Boost library. The default is 600 seconds. • -DWITH_CLIENT_PROTOCOL_TRACING= bool • -DWITH_CURL= curl_type • -DWITH_DEBUG= bool 236 Configuring MySQL with debugging support enables you to use the  --debug="d,parser_debug" option when you start the server. This causes the Bison parser that is used to process SQL statements Whether to include debugging support. The location of the  curl  library.  curl_type  can be  system  (use the system  curl  library) or a path name to the  curl  library. See also the  WITH_TEST_TRACE_PLUGIN  option. For information about writing protocol trace client plugins, see Writing Protocol Trace Plugins. Whether to build the client-side protocol tracing framework into the client library. By default, this option is enabled. With the above settings that allow Boost download into a specified location, when the required Boost version changes, you need to remove the  bld  folder, recreate it, and perform the  cmake  step again. Otherwise, the new Boost version might not get downloaded, and compilation might fail. If Boost is already installed locally and your compiler finds the Boost header files on its own, it may not be necessary to specify the preceding  CMake  options. However, if the version of Boost required by MySQL changes and the locally installed version has not been upgraded, you may have build problems. Using the  CMake  options should give you a successful build. This causes Boost to be downloaded into the  my_boost  directory under your home directory. If the required Boost version is already there, no download is done. If the required Boost version changes, the newer version is downloaded. For example, if you normally build MySQL placing the object output in the  bld  subdirectory of your MySQL source tree, you can build with Boost like this: mkdir bld cd bld cmake .. -DDOWNLOAD_BOOST=ON -DWITH_BOOST=$HOME/my_boost The Boost library is required to build MySQL. These  CMake  options enable control over the library source location, and whether to download it automatically: -DWITH_BOOST=system  is also permitted and indicates that the correct version of Boost is installed on the compilation host in the standard location. In this case, the installed version of Boost is used rather than any version included with a MySQL source distribution.