Hadoop vendor - Download and install the driver made available by the Hadoop cluster provider (Cloudera, MapR, etc.). To locate the driver please consult the vendor's website.
RStudio Professional Drivers - RStudio Workbench (formerly RStudio Server Pro), RStudio Desktop Pro, RStudio Connect, or Shiny Server Pro users can download and use RStudio Professional Drivers at no additional charge. These drivers include an ODBC connector for Apache Impala. RStudio delivers standards-based, supported, professional ODBC drivers. Use RStudio Professional Drivers when you run R or Shiny with your production systems. See the RStudio Professional Drivers for more information.
odbc package, in combination with a driver, provides
DBI support and an ODBC connection.
There are six settings needed to make a connection:
- Driver - See the Drivers section for setup information
- Host - A network path to the database server
- Schema - The name of the schema
- UID - The user's network ID or server local account
- PWD - The account's password
- Port - Should be set to 21050
con <- DBI::dbConnect(odbc::odbc(), Driver = "[your driver's name]", Host = "[your server's path]", Schema = "[your schema's name]", UID = rstudioapi::askForPassword("Database user"), PWD = rstudioapi::askForPassword("Database password"), Port = 21050)
Switching from Impala to Hive#
If you create a table in Impala and then drop the Hive metadata, you will need to invalidate the Impala metadata.
impala_con <- dbConnect(odbc::odbc(), "Impala") dbWriteTable(impala_con, "mtcars", mtcars) hive_con <- dbConnect(odbc::odbc(), "Hive") dbRemoveTable(hive_con, "mtcars") dbReadTable(impala_con, "mtcars") # succeeds dbExistsTable(impala_con, "mtcars") # fails dbGetQuery(odbcCon, "INVALIDATE METADATA mtcars") dbExistsTable(impala_con, "mtcars") # succeeds
This happens because dropping the Hive metadata does not drop the Impala metadata. More information can be found in the Cloudera documentation here.