Looking for libpq.so.4
I had always been building Slony from source, but for the first time I tried using the community version from “pgrpms.org”. I was using PostgreSQL version 8.3 so it was really easy to find the correct rpms at http://www.pgrpms.org/8.3/redhat/rhel-5-x86_64/ but as I tried installing Slony package I was hit with an error:
"libpq.so.4 not found"
This looked really weird to me as I already had the libpq library installed as libpq.so.5 but it was still looking for libpq.so.4.
Looking for a solution I started going through the 8.3 RPMs and tried looking for file libpq.so.4 file…. bingooo!!! I found one which had it. compat-postgresql-libs was the answer to this problem.
After installing that package, Slony got installed successfully without any problems.