Github user HyukjinKwon commented on the issue:
https://github.com/apache/spark/pull/18465
I referred this - http://adv-r.had.co.nz/Rcpp.html and your link.
I did as below:
**R test alone**
```
vi tmp.R
```
copy and paste the codes in **Before** and **After** and then ran
```
Rscript tmp.R
```
Before
```R
library(Rcpp)
cppFunction('double takeLog(double val) {
try {
if (val <= 0.0) { // log() not defined here
throw std::range_error("Inadmissible value");
}
return log(val);
} catch(std::exception &ex) {
forward_exception_to_r(ex);
} catch(...) {
::Rf_error("c++ exception (unknown reason)");
}
return NA_REAL; // not reached
}')
for(i in 0:10000) {
p <- parallel:::mcfork()
if (inherits(p, "masterProcess")) {
takeLog(-1.0)
print("unreachable")
tools::pskill(child, tools::SIGUSR1)
}
}
print("end")
Sys.sleep(10L)
```
After
```R
library(Rcpp)
cppFunction('double takeLog(double val) {
try {
if (val <= 0.0) { // log() not defined here
throw std::range_error("Inadmissible value");
}
return log(val);
} catch(std::exception &ex) {
forward_exception_to_r(ex);
} catch(...) {
::Rf_error("c++ exception (unknown reason)");
}
return NA_REAL; // not reached
}')
for(i in 0:10000) {
p <- parallel:::mcfork()
if (inherits(p, "masterProcess")) {
takeLog(-1.0)
print("unreachable")
}
children <- suppressWarnings(parallel:::selectChildren(timeout = 0))
if (is.integer(children)) {
lapply(children, function(child) {
print(parallel:::readChild(child))
tools::pskill(child, tools::SIGUSR1)
})
}
}
print("end")
Sys.sleep(10L)
```
The symptoms are similar with
https://github.com/apache/spark/pull/18465#issuecomment-313049544
**End to end**
I could not do this as I did above with `cppFunction` due to such errors
below:
```
Error in as.character(node[[1]]) :
cannot coerce type 'builtin' to vector of type 'character'
```
So, I did as below:
```
vi takeLog.cpp
```
copy and paste
```cpp
#include <Rcpp.h>
using namespace Rcpp;
// [[Rcpp::export]]
double takeLog(double val) {
try {
if (val <= 0.0) { // log() not defined here
throw std::range_error("Inadmissible value");
}
return log(val);
} catch(std::exception &ex) {
forward_exception_to_r(ex);
} catch(...) {
::Rf_error("c++ exception (unknown reason)");
}
return NA_REAL; // not reached
}
```
And then ran below with SparkR:
```R
func <- function(key, x) {
library(Rcpp)
path <- "/.../spark/takeLog.cpp"
sourceCpp(path)
takeLog(-1.0)
}
df <- createDataFrame(list(list(1L, 1, "1", 0.1)), c("a", "b", "c", "d"))
collect(gapply(df, "a", func, schema(df)))
... 30 times
collect(gapply(df, "a", function(key, x) { x }, schema(df)))
```
The symptoms are also similar with
https://github.com/apache/spark/pull/18465#issuecomment-313055990 for both
before/after.
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