install perl DBD::Oracle (Lesson learned: CPAN and yum don't mix)

From the many tales of woe on the web about installing perl DBD::Oracle, from "invalid lvalue in assignment" to mysterious make errors, and the pages of intricate instructions doubtfully translated from the French, I assumed that it was a long and difficult process and it was natural that I was having problems installing on 64-bit CentOS. WRONG! It can actually be easy for lazy and dumb people like me.

First, just use yum and hand-compiling. Don't add CPAN to the mix.

1. Add the rpmforge repo and the EPEL repo (see links for instructions) so that you can install perl-DBD and perl-DBI via yum.
2. Install perl-DBD and perl-DBI via yum.
3. Download and install the OCI client "basic" and "sdk/devel" packages from Oracle. Note that you might need an older version if you're connecting to an older version of Oracle. Note also that Oracle makes you log in to download this. Note also that you need both the SDK and the Basic package. I recommend getting the rpms - install with a simple rpm -Uvh .
4. Oracle puts the libraries in a wacky place, e.g. /usr/lib/oracle/11.2/client64/lib if you're using the 64-bit version of 11.2. Therefore, create a new file, e.g. oci.conf, in /etc/ld.so.conf.d/, with the library location in it, and then run (as root) ldconfig -v to add it.
5. Download the DBD::Oracle source from cpan and extract it someplace. 
6. Set some environment variables:
   

   export ORACLE_HOME=/usr/lib/oracle/11.2/client64
   export PATH=$PATH:$ORACLE_HOME/bin
   export LD_LIBRARY_PATH=$ORACLE_HOME/lib

7. Run "perl Makefile.PL -V 11.2.0" in the directory where the OCI client was extracted. Change the version number to whatever the correct version is. This avoids the "I could not determine Oracle client version so I'll just default to version 8.0.0.0" issue.
8. Run "make install".
9. You should be done!

The latest versions of the Oracle Instant Client default to making incredibly verbose logs in the user's home directories - how to disable default oradiag_user instant client logging.

perl cpan "recursive dependency detected"

Using the CPAN shell for the first time on a new server, after install Bundle::CPAN" and then "reload cpan", on the next install I got:

Recursive dependency detected:
    Bundle::CPAN
 => ExtUtils::MakeMaker
 => M/MS/MSCHWERN/ExtUtils-MakeMaker-6.56.tar.gz
 => File::Spec
 => S/SM/SMUELLER/PathTools-3.33.tar.gz
 => File::Path
 => D/DL/DLAND/File-Path-2.08.tar.gz
 => File::Spec.
Cannot continue.

in the perl cpan installer. Alas! I thought. Will I have to install the old-fashioned way? Indeed no! This may just be a sign that you need to "install Bundle::CPAN" and then "reload cpan".

But I just did that, damn it! Apparently, "reload cpan" isn't always completely effective after "install Bundle::CPAN". If you encounter this error, try quitting cpan and reloading.

Proof yet again that almost all tech problems can be solved by restarting the (whatever).

Btw, if you're not using the CPAN shell, use perl -MCPAN -e 'install( q{Bundle::CPAN} )' to install/update the cpan bundle.