What jar does SparkR use to parse R syntaxes - sparkr

Question

I am a newbie on SparkR, so would like to ask about what jar does SparkR use to parse the R syntaxes

Answer 1

I hope that I understood you correctly and that your assumption is that R code will be translated into Java code. So my short answer would be that SparkR uses no jars to parse R syntaxes.
The longer explanation:
Well, SparkR is written in R and when you create a sparkR.session(), a local Spark driver JVM will be created and a socket connection between your R instance and the JVM will be established. SparkR functions are more or less wrappers for Spark SQL methods written in Scala which exist on the Spark side and will be called using the socket connection. The function arguments or whole functions will be serialized in a custom format, sent to the JVM, and eventually the Spark executors will execute the (deserialized) R code in an R instance which is used by the Spark cluster.
The serialization and deserialization code is located in /R/pkg/R/serialize.R and /R/pkg/R/deserialize.R of your Spark distribution. R/pkg/inst/worker/worker.R executes the R code in the Spark cluster.
An older architecture overview with more details can be found here:
https://cs.stanford.edu/~matei/papers/2016/sigmod_sparkr.pdf
There are two kinds of RPCs we support in the SparkR JVM backend:
method invocation and creating new objects. Method invocations are
called using a reference to an existing Java object (or class name for
static methods) and a list of arguments to be passed on to the method.
The arguments are serialized using our custom wire format which is
then deserialized on the JVM side. We then use Java reflection to
invoke the appropriate method. In order to create objects, we use a
special method name init and then similarly invoke the appropriate
constructor based on the provided arguments. Finally, we use a new R
class ’jobj’ that refers to a Java object existing in the backend.
These references are tracked on the Java side and are automatically
garbage collected when they go out of scope on the R side.