rafal-c opened a new issue, #43496:
URL: https://github.com/apache/arrow/issues/43496
### Describe the bug, including details regarding any error messages,
version, and platform.
Consider a simple program (code below) which creates a Table, turns it into
a Dataset and writes the Dataset with Filename partitioning to a directory
`/tmp/dataset`. Let's call it `myprogram`. Now if you run `myprogram` and look
into /tmp/dataset repeatedly, this is what you may see:
```bash
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2020_part0.parquet 2021_part0.parquet
2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2020_part0.parquet 2021_part0.parquet
2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2020_part0.parquet 2021_part0.parquet
2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2020_part0.parquet 2021_part0.parquet 2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2020_part0.parquet 2021_part0.parquet
2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2020_part0.parquet 2021_part0.parquet
2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2020_part0.parquet 2021_part0.parquet 2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2020_part0.parquet 2021_part0.parquet
2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2019_part0.parquet 2021_part0.parquet 2022_part0.parquet
➜ ./myprogram && ls /tmp/dataset
2020_part0.parquet 2021_part0.parquet 2022_part0.parquet
```
So for some reason it randomly skips parts of the dataset on write. This is
not specific to Parquet and it happens on all major platforms
(Linux/Windows/MacOS) with Arrow 16.0.0.
Here is the full code to reproduce:
```cpp
#include <arrow/api.h>
#include <arrow/dataset/api.h>
#include <arrow/filesystem/api.h>
arrow::Result<std::shared_ptr<arrow::Table>> makeTable() {
using arrow::field;
auto schema = arrow::schema({field("a", arrow::int64()), field("year",
arrow::int64())});
std::vector<std::shared_ptr<arrow::Array>> arrays(2);
arrow::NumericBuilder<arrow::Int64Type> builder;
ARROW_RETURN_NOT_OK(builder.AppendValues({5, 2, 4, 100, 2, 4}));
ARROW_RETURN_NOT_OK(builder.Finish(&arrays[0]));
builder.Reset();
ARROW_RETURN_NOT_OK(builder.AppendValues({2019, 2020, 2021, 2021, 2022,
2022}));
ARROW_RETURN_NOT_OK(builder.Finish(&arrays[1]));
return arrow::Table::Make(schema, arrays);
}
int main() {
namespace ds = arrow::dataset;
// Create an Arrow Table
auto table = makeTable().ValueOrDie();
auto dataset = std::make_shared<ds::InMemoryDataset>(table);
auto scanner_builder = dataset->NewScan().ValueOrDie();
auto scanner = scanner_builder->Finish().ValueOrDie();
// The partition schema determines which fields are part of the
partitioning.
auto partition_schema = arrow::schema({arrow::field("year",
arrow::int64())});
auto partitioning =
std::make_shared<ds::FilenamePartitioning>(partition_schema);
// We'll write Parquet files.
auto format = std::make_shared<ds::ParquetFileFormat>();
ds::FileSystemDatasetWriteOptions write_options;
write_options.file_write_options = format->DefaultWriteOptions();
write_options.existing_data_behavior =
ds::ExistingDataBehavior::kDeleteMatchingPartitions;
write_options.filesystem =
std::make_shared<arrow::fs::LocalFileSystem>();;
write_options.base_dir = "/tmp/dataset";
write_options.partitioning = partitioning;
write_options.basename_template = "part{i}.parquet";
return ds::FileSystemDataset::Write(write_options, scanner) !=
arrow::Status::OK();
}
```
### Component(s)
C++
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