Stochastic Nonsense

Querying Postgres or Greenplum From R on a Mac, Installation Instructions

NB: this works on 64b versions of R; I tested it with the R64 app with R version 2.10.1 on Snow Leopard

Step by step instructions for talking to Postgres or Greenplum:

1. install macports
2. install postgres; I used 8.4
   

   sudo port install postgresql84
   

3. in a shell, create an environmental variable PG_CONFIG pointing to the pg_config binary installed by postgres. In my installation, this is something like
   

   export PG_CONFIG=/opt/local/lib/postgresql84/bin/pg_config
   

4. in the same shell, tell R to install the RPostgreSQL package *from source*, ie
   

   $ R
   > install.packages('RPostgreSQL', type='source')
   

5. test the installation works:
   

   > library('RPostgreSQL')
   Loading required package: DBI
   > drv <- dbDriver('PostgreSQL')
   > db <- dbConnect(drv, host='greenplum.ip', user='earl', dbname='dbname')
   > dbGetQuery(db, 'select 1')
   ?column?
   1       1
   

Diagnosing error messages / problems:

• If R says
  

  Warning message:
  In install.packages("RPostgreSQL") : package ‘RPostgreSQL’ is not available
  

  
  you must specify to install the package from source, as above with type=’source’

• If you get compilation errors when installing the package that mention libpq-fe.h, then R can’t find pg_config
• if the package installs but when loading it you get errors involving missing symbol _PQbackendPID then you are mixing 32 and 64 bit software.

Follow the links for instructions to fix your problems.