In ORE there are a number ways to get you R scripts to run in parallel in the database. One way is to enable the Parallel option in ORE. This is what will be shown in this post. There are other methods of running various ORE commands/scripts in parallel. With these the scripts are divided out and several parallel R processes are started on the server.
But what if you want to use the database parallel feature on some of your ORE other commands?
Why would you want to do this?
Well the main answer is that you might want to use the parallel option of the database for the creation on objects (tables etc) and for selecting and manipulating the data in the database.
How can you enable your ORE connection to use the in-database parallel feature?
ORE 1.4 has a new option that enables the parallel option for your ORE connection in the database. This option is called ore.parallel.
When you enable or set the ore.parallel option, it seems to be the equivalent of running the following:
ALTER SESSION ENABLE PARALLEL DDL;
ALTER SESSION ENABLE PARALLEL DML;
ALTER SESSION ENABLE PARALLEL QUERY;
The exact details is a little unclear, but it seems to be above commands.
The following commands illustrates some options for using the ore.parallel option.
> # Check to see if the ore.parallel is enabled for your ORE connection
The NULL returned value tells us that your ORE connections does not have the Parallel option enabled. If the schema had Parallel enabled by default then we would have have a response of TRUE.
The following command turns on the Parallel option for your ORE connection / schema.
> options(“ore.parallel” = TRUE)
When the Parallel option is enabled (TRUE above) the database will use the degree of parallel that is set as default for the schema or the degree of parallel that is defined for the table when it is being used in your ORE commands.
You can changed the degree of parallelism by passing the required degree as a value to the ore.parallel command. In the following, the degree of parallelism is set to 8. We then as ORE what the degree is set to and it tells us that it is 8. So it was set correctly.
> options(“ore.parallel” = 8)