Trying to get RmySQL to work but not understanding bash's export or filesystem conventions - mysql

Question

I am trying to install RMySQL on my mac (mavericks) and it errors out when I try to build it from source, saying:
Configuration error: could not find the MySQL installation include
and/or library directories. Manually specify the location of the
MySQL libraries and the header files and re-run R CMD INSTALL.
INSTRUCTIONS:
Define and export the 2 shell variables PKG_CPPFLAGS and PKG_LIBS to include the directory for header files (*.h) and
libraries, for example (using Bourne shell syntax):
export PKG_CPPFLAGS="-I"
export PKG_LIBS="-L -lmysqlclient"
Re-run the R INSTALL command:
R CMD INSTALL RMySQL_.tar.gz
I tried to follow the instructions by entering:
export PKG_CPPFLAGS="-I/usr/local/mysql/include" export
PKG_LIBS="-L/usr/local/mysql/lib -lmysqlclient"
but when I re-run RMySQL it still doesn't work. Moreover, if I type
$PKG_LIBS
to see what that variable holds, I get
-bash: -L/usr/local/mysql/lib: No such file or directory'
I know that /usr/local/mysql/lib exists and it does contain a mySQL header. Am I misunderstanding the instructions?
I'm asking here only after a lot of effort to find solutions and/or work arounds. Sucks being a noob sometimes.

Answer 1

I am going to assume you're trying to get RmySQL to run on R 3.1.0 on Mavericks? Rather than worry about exporting variables etc, here is a simple clean solution for you that should avoid the headaches.
The RMySQL install link Pascal provided above really is your solution. You're probably just stumbling on syntax, or getting things to work from the terminal.
Even if you're a "noob", you should be able to get this working. I'll try to offer a "dummy's guide" walk through here, as I bet there are many others who have this problem too, even after trying to read the RMySQL installation readme.
I would bet with very high confidence the problem is just that you aren't specifying correctly the locations of the library and header folders for compiling. Read the errors carefully when you try to compile... the errors will probably tell you a file/header is missing, or some .so file (shared object) is missing.
One simple way compile RMySQL from source on R 3.1.0, mavericks is as follows (this does not require you to set any environmental variables, no editing of the Renviron file, etc):
Does MySQL work by itself? i.e. Can you open/run it no problems? If not, fix that first.
Find the precise location of your mysql installation. For me, on Mavericks, I see mysql installed at /usr/local/mysql-5.6.17-osx10.7-x86_64 (your version number may be different). There is also another folder /usr/local/mysql which is an alias to /usr/local/mysql-5.6.17-osx10.7-x86_64 (/usr/local/mysql finds the current version of mysql you are using, if multiple mysql file folders exist, I think). In this directory, I see two sub directories (among many) called "include" and "lib". Take a look; "include" will contain header files (include as in #include , etc, in simple C++ programs). The "lib" folder contains compiled source code of the mysql library.
An easy way to compile and install RMySQL which doesn't exactly follow the suggested way to do it in the installation guide is this. Note that this is doing the same thing as in the installation guide, just a little easier as it's one command line from the terminal, once you know where your mysql install folder is. Go to the terminal, and type the following exactly, with one space between each chunk (with your mysql folder name adjusted appropriately for the version number):
PKG_CPPFLAGS="-I/usr/local/mysql/include/" PKG_LIBS="-L/usr/local/mysql/lib/ -lmysqlclient" R CMD INSTALL RMySQL_0.9-3.tar.gz
OR (the same thing, just more typing)
PKG_CPPFLAGS="-I/usr/local/mysql-5.6.17-osx10.7-x86_64/include/" PKG_LIBS="-L/usr/local/mysql-5.6.17-osx10.7-x86_64/lib/ -lmysqlclient" R CMD INSTALL RMySQL_0.9-3.tar.gz
Note for dummies: Make sure when you run this command, that you are doing it from the terminal in the directory that contains the RMySQL_0.9-3.tar.gz file (or whatever the name of your folder is that contains the RMySQL source code)
and RMySQL compiles!
Don't be afraid about trying to compile source code -- it's not just for 'compiled language programmers' or 'computer science graduates'. Most of the time when compiling fails it's just because files are "missing" (there is no corruption on the source code) -- the user hasn't properly specified the locations of the header and libraries (shared objects). Now pull your big boy/girl panties up and just do it .... it's easy.
Notes for people clueless about compiling source code for packages in R:
a) pay special attention to the spacing in the above, otherwise it may not work. Do not have any spaces between the = and the variable/file names (e.g. don't try and have in the above PKG_CPPFLAGS ="-I/usr/local/mysql/include/" as it won't work)
b) When compiling, you want to specify the locations of the header files and the library files and this is what the "-I/ .... " and "-L/ ...." are doing. The -I directory specifies the location of the header files, and the -L the location of the library files. The library files also require the -l[name of library] extension (the -l is short for -lib in the library object names).
c) Note that in the directory /usr/local/mysql-5.6.17-osx10.7-x86_64/lib/ I do not see a file called "lmysqlclient", or even "libmysqlclient", but I do see files named (among others) "libmysqlclient.a" and "libmysqlclient.18.dylib". So don't worry about your MySQL installation not being correct if you don't see a file just called "libmysqlclient" in the lib folder.