Catch error message on dbConnect failure

[Matt K]

When dbConnect fails, for reasons like when the Postgres connection limit is reached, the error returned does not include the error message, only:

Error in postgresqlNewConnection(drv, ...) :
RS-DBI driver: (could not connect ...)
Calls: dbConnect -> dbConnect -> postgresqlNewConnection -> .Call
Execution halted

This comment suggests that it might be an RPostgreSQL issue, as the MySQL driver does return some error detail: http://stackoverflow.com/questions/38086738/print-dbconnect-exception-in-r#comment63612612_38086738




Wrapping the connection in a tryCatch does not provide any additional message detail, and dbGetException() requires a connection object, which of course does not exist.




Is this a limitation in the currenr RPostgreSQL error handler?




con <- tryCatch(
    { dbConnect(drv, host = "***", dbname = "***", user = "***") },
    error=function(cond) {
        message("DB conn failed")
        message(cond)
        return(NA)
    }
)