westonpace commented on pull request #9899:
URL: https://github.com/apache/arrow/pull/9899#issuecomment-813791413
> The error on centos7 is something that I see on about 1 out of every 10
runs locally on the as.data.frame(RecordBatch) test. Locally it looks like:
>
> ```
> libc++abi.dylib: Pure virtual function called!
> /bin/sh: line 1: 93200 Abort trap: 6
> ```
>
> I haven't observed this on repeated runs of the array/chunked-array tests.
>
> Any ideas @romainfrancois @bkietz? Even though my changes are purely in
the R code, googling the error message suggests it's a C++ issue.
It's a bug in `to_dataframe_parallel` (or possibly somewhere deeper).
Something is calling `stop` which is causing the code to bail before `tg` (the
`arrow::internal::TaskGroup`) is destroyed. The converters are then destroyed
first for whatever reason (I don't really know how R cleans this stuff up).
When the `TaskGroup` is destroyed it waits until all running tasks cease.
Since this hasn't happened the tasks are still running. The tasks reference
`this` implicitly where `this` is the converter. Thus, the tasks have a
pointer to an object that has been destroyed and they attempt to make a call on
it. This yields the error you saw.
A quick patch (but I'm not sure if the right one as I don't understand R's
`stop` well enough) could be...
```
diff --git a/r/src/array_to_vector.cpp b/r/src/array_to_vector.cpp
index ddcb74946..ef57fa660 100644
--- a/r/src/array_to_vector.cpp
+++ b/r/src/array_to_vector.cpp
@@ -88,11 +88,12 @@ class Converter {
// for each array, add a task to the task group
//
// The task group is Finish() in the caller
- void IngestParallel(SEXP data, const
std::shared_ptr<arrow::internal::TaskGroup>& tg) {
+ void IngestParallel(SEXP data, const
std::shared_ptr<arrow::internal::TaskGroup>& tg,
+ std::shared_ptr<Converter> self) {
R_xlen_t k = 0, i = 0;
for (const auto& array : arrays_) {
auto n_chunk = array->length();
- tg->Append([=] { return IngestOne(data, array, k, n_chunk, i); });
+ tg->Append([=] { return self->IngestOne(data, array, k, n_chunk, i);
});
k += n_chunk;
i++;
}
@@ -1242,7 +1243,7 @@ cpp11::writable::list to_dataframe_parallel(
// add a task to ingest data of that column if that can be done in
parallel
if (converters[i]->Parallel()) {
- converters[i]->IngestParallel(column, tg);
+ converters[i]->IngestParallel(column, tg, converters[i]);
}
}
```
This copies the `shared_ptr` into the task and uses that (instead of an
implicit `this` capture).
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