[R] RPostgreSQL && snowfall

[Whit Armstrong]

I don't think you can share dbi connections across different instances of R.

just have each of your helper functions open a local connection.  or
alternatively, load a package on each instance which keeps a dbi
connection open.

and make sure you bump up your allowed number of connections in
pg_conf if you need to.

-Whit


On Mon, Jun 6, 2011 at 12:40 PM, Florian Endel <florian at endel.at> wrote:
> Dear expeRts,
>
> I'm currently trying to get data from a PostgreSQL database _in parallel_.
> I tried two methods:
> * passing the DBI Connection object to the cluster nodes
> * connecting the the DB on each node
>
> (1)
> The execution of the first method looks like this:
>> result = sfClusterApplyLB(input, fun, dbiCon)
> and produces an "expired PostgreSQLConnection" error.
> (Of course the passed Connection Object is usable at that moment and
> afterwards!)
>
> (2)
> For the creation of DB connections on every node a function handling
> the whole connection is sourced into every node.
> This function works perfectly without snowfall.
> Calling it with
>> sfClusterEval(dbConnect())
> again only expired connection objects are produced. Even if I create
> the connection 'a line above' the code which is connecting to the DB
> it doesn't work...
>
>
> Is there a possibility to connect to PostgreSQL using snowfall?
>
> --
> with kind regards
> Florian
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>