Support smallest_decimal_enabled flag in pyarrow

cpp/src/arrow/dataset/file_parquet.cc

@@ -132,6 +132,8 @@ parquet::ArrowReaderProperties MakeArrowReaderProperties(
       parquet_scan_options.arrow_reader_properties->cache_options());
   arrow_properties.set_io_context(
       parquet_scan_options.arrow_reader_properties->io_context());
+  arrow_properties.set_smallest_decimal_enabled(
+      parquet_scan_options.arrow_reader_properties->smallest_decimal_enabled());
   arrow_properties.set_use_threads(options.use_threads);
   return arrow_properties;
 }
@@ -532,7 +534,7 @@ Future<std::shared_ptr<parquet::arrow::FileReader>> ParquetFileFormat::GetReader
                                                      metadata)
             .Then(
                 [=](const std::unique_ptr<parquet::ParquetFileReader>& reader) mutable
-                -> Result<std::shared_ptr<parquet::arrow::FileReader>> {
+                    -> Result<std::shared_ptr<parquet::arrow::FileReader>> {
                   auto arrow_properties = MakeArrowReaderProperties(
                       *self, *reader->metadata(), *options, *parquet_scan_options);
 

cpp/src/parquet/arrow/arrow_reader_writer_test.cc

@@ -15,7 +15,6 @@
 // specific language governing permissions and limitations
 // under the License.
 
-#include "parquet/properties.h"
 #ifdef _MSC_VER
 #  pragma warning(push)
 // Disable forcing value to bool warnings

cpp/src/parquet/arrow/writer.cc

@@ -300,9 +300,9 @@ class FileWriterImpl : public FileWriter {
     }
   }
 
-  Status Init(const ArrowReaderProperties& schema_arrow_reader_properities) {
+  Status Init(const ArrowReaderProperties& schema_arrow_reader_properties) {
     return SchemaManifest::Make(writer_->schema(), /*schema_metadata=*/nullptr,
-                                schema_arrow_reader_properities, &schema_manifest_);
+                                schema_arrow_reader_properties, &schema_manifest_);
   }
 
   Status NewRowGroup() override {
@@ -516,10 +516,10 @@ Status FileWriter::Make(::arrow::MemoryPool* pool,
                         std::shared_ptr<::arrow::Schema> schema,
                         std::shared_ptr<ArrowWriterProperties> arrow_properties,
                         std::unique_ptr<FileWriter>* out,
-                        const ArrowReaderProperties& schema_arrow_reader_properities) {
+                        const ArrowReaderProperties& schema_arrow_reader_properties) {
   std::unique_ptr<FileWriterImpl> impl(new FileWriterImpl(
       std::move(schema), pool, std::move(writer), std::move(arrow_properties)));
-  RETURN_NOT_OK(impl->Init(schema_arrow_reader_properities));
+  RETURN_NOT_OK(impl->Init(schema_arrow_reader_properties));
   *out = std::move(impl);
   return Status::OK();
 }
@@ -556,7 +556,7 @@ Result<std::unique_ptr<FileWriter>> FileWriter::Open(
     std::shared_ptr<::arrow::io::OutputStream> sink,
     std::shared_ptr<WriterProperties> properties,
     std::shared_ptr<ArrowWriterProperties> arrow_properties,
-    const ArrowReaderProperties& schema_arrow_reader_properities) {
+    const ArrowReaderProperties& schema_arrow_reader_properties) {
   std::shared_ptr<SchemaDescriptor> parquet_schema;
   RETURN_NOT_OK(
       ToParquetSchema(&schema, *properties, *arrow_properties, &parquet_schema));
@@ -575,7 +575,7 @@ Result<std::unique_ptr<FileWriter>> FileWriter::Open(
   auto schema_ptr = std::make_shared<::arrow::Schema>(schema);
   RETURN_NOT_OK(Make(pool, std::move(base_writer), std::move(schema_ptr),
                      std::move(arrow_properties), &writer,
-                     schema_arrow_reader_properities));
+                     schema_arrow_reader_properties));
 
   return writer;
 }
@@ -596,12 +596,12 @@ Status WriteTable(const ::arrow::Table& table, ::arrow::MemoryPool* pool,
                   std::shared_ptr<::arrow::io::OutputStream> sink, int64_t chunk_size,
                   std::shared_ptr<WriterProperties> properties,
                   std::shared_ptr<ArrowWriterProperties> arrow_properties,
-                  const ArrowReaderProperties& schema_arrow_reader_properities) {
+                  const ArrowReaderProperties& schema_arrow_reader_properties) {
   std::unique_ptr<FileWriter> writer;
   ARROW_ASSIGN_OR_RAISE(
       writer,
       FileWriter::Open(*table.schema(), pool, std::move(sink), std::move(properties),
-                       std::move(arrow_properties), schema_arrow_reader_properities));
+                       std::move(arrow_properties), schema_arrow_reader_properties));
   RETURN_NOT_OK(writer->WriteTable(table, chunk_size));
   return writer->Close();
 }

cpp/src/parquet/arrow/writer.h

@@ -58,7 +58,7 @@ class PARQUET_EXPORT FileWriter {
       std::shared_ptr<::arrow::Schema> schema,
       std::shared_ptr<ArrowWriterProperties> arrow_properties,
       std::unique_ptr<FileWriter>* out,
-      const ArrowReaderProperties& schema_arrow_reader_properities =
+      const ArrowReaderProperties& schema_arrow_reader_properties =
           default_arrow_reader_properties());
 
   /// \brief Try to create an Arrow to Parquet file writer.
@@ -76,7 +76,7 @@ class PARQUET_EXPORT FileWriter {
       std::shared_ptr<WriterProperties> properties = default_writer_properties(),
       std::shared_ptr<ArrowWriterProperties> arrow_properties =
           default_arrow_writer_properties(),
-      const ArrowReaderProperties& schema_arrow_reader_properities =
+      const ArrowReaderProperties& schema_arrow_reader_properties =
           default_arrow_reader_properties());
 
   /// Return the Arrow schema to be written to.
@@ -183,7 +183,7 @@ WriteTable(const ::arrow::Table& table, MemoryPool* pool,
            std::shared_ptr<WriterProperties> properties = default_writer_properties(),
            std::shared_ptr<ArrowWriterProperties> arrow_properties =
                default_arrow_writer_properties(),
-           const ArrowReaderProperties& schema_arrow_reader_properities =
+           const ArrowReaderProperties& schema_arrow_reader_properties =
                default_arrow_reader_properties());
 
 }  // namespace arrow

python/pyarrow/_dataset_parquet.pyx

@@ -703,7 +703,7 @@ cdef class ParquetFragmentScanOptions(FragmentScanOptions):
     cache_options : pyarrow.CacheOptions, default None
         Cache options used when pre_buffer is enabled. The default values should
         be good for most use cases. You may want to adjust these for example if
-        you have exceptionally high latency to the file system. 
+        you have exceptionally high latency to the file system.
     thrift_string_size_limit : int, default None
         If not None, override the maximum total string size allocated
         when decoding Thrift structures. The default limit should be
@@ -720,6 +720,11 @@ cdef class ParquetFragmentScanOptions(FragmentScanOptions):
         Parquet file.
     page_checksum_verification : bool, default False
         If True, verify the page checksum for each page read from the file.
+    page_checksum_verification : bool, default False
+        If True, verify the page checksum for each page read from the file.
+    smallest_decimal_enabled : bool, default False
+        If True, always convert to the smallest arrow decimal type based
+        on precision.
     """
 
     # Avoid mistakingly creating attributes
@@ -733,7 +738,8 @@ cdef class ParquetFragmentScanOptions(FragmentScanOptions):
                  thrift_container_size_limit=None,
                  decryption_config=None,
                  decryption_properties=None,
-                 bint page_checksum_verification=False):
+                 bint page_checksum_verification=False,
+                 bint smallest_decimal_enabled=False):
         self.init(shared_ptr[CFragmentScanOptions](
             new CParquetFragmentScanOptions()))
         self.use_buffered_stream = use_buffered_stream
@@ -752,6 +758,7 @@ cdef class ParquetFragmentScanOptions(FragmentScanOptions):
         if decryption_properties is not None:
             self.decryption_properties = decryption_properties
         self.page_checksum_verification = page_checksum_verification
+        self.smallest_decimal_enabled = smallest_decimal_enabled
 
     cdef void init(self, const shared_ptr[CFragmentScanOptions]& sp):
         FragmentScanOptions.init(self, sp)
@@ -868,6 +875,14 @@ cdef class ParquetFragmentScanOptions(FragmentScanOptions):
     def page_checksum_verification(self, bint page_checksum_verification):
         self.reader_properties().set_page_checksum_verification(page_checksum_verification)
 
+    @property
+    def smallest_decimal_enabled(self):
+        return self.arrow_reader_properties().smallest_decimal_enabled()
+
+    @smallest_decimal_enabled.setter
+    def smallest_decimal_enabled(self, bint smallest_decimal_enabled):
+        self.arrow_reader_properties().set_smallest_decimal_enabled(smallest_decimal_enabled)
+
     def equals(self, ParquetFragmentScanOptions other):
         """
         Parameters

python/pyarrow/_parquet.pxd

@@ -405,6 +405,8 @@ cdef extern from "parquet/api/reader.h" namespace "parquet" nogil:
         CCacheOptions cache_options() const
         void set_coerce_int96_timestamp_unit(TimeUnit unit)
         TimeUnit coerce_int96_timestamp_unit() const
+        void set_smallest_decimal_enabled(c_bool smallest_decimal_enabled)
+        c_bool smallest_decimal_enabled() const
 
     ArrowReaderProperties default_arrow_reader_properties()
 

python/pyarrow/_parquet.pyx

@@ -1441,7 +1441,8 @@ cdef class ParquetReader(_Weakrefable):
              FileDecryptionProperties decryption_properties=None,
              thrift_string_size_limit=None,
              thrift_container_size_limit=None,
-             page_checksum_verification=False):
+             page_checksum_verification=False,
+             smallest_decimal_enabled=False):
         """
         Open a parquet file for reading.
 
@@ -1458,6 +1459,7 @@ cdef class ParquetReader(_Weakrefable):
         thrift_string_size_limit : int, optional
         thrift_container_size_limit : int, optional
         page_checksum_verification : bool, default False
+        smallest_decimal_enabled : bool, default False
         """
         cdef:
             shared_ptr[CFileMetaData] c_metadata
@@ -1497,6 +1499,7 @@ cdef class ParquetReader(_Weakrefable):
                 decryption_properties.unwrap())
 
         arrow_props.set_pre_buffer(pre_buffer)
+        arrow_props.set_smallest_decimal_enabled(smallest_decimal_enabled)
 
         properties.set_page_checksum_verification(page_checksum_verification)
 

python/pyarrow/parquet/core.py

@@ -255,6 +255,9 @@ class ParquetFile:
         it will be parsed as an URI to determine the filesystem.
     page_checksum_verification : bool, default False
         If True, verify the checksum for each page read from the file.
+    smallest_decimal_enabled : bool, default False
+        If True, always convert to the smallest arrow decimal type based
+        on precision.
 
     Examples
     --------
@@ -303,7 +306,7 @@ def __init__(self, source, *, metadata=None, common_metadata=None,
                  pre_buffer=False, coerce_int96_timestamp_unit=None,
                  decryption_properties=None, thrift_string_size_limit=None,
                  thrift_container_size_limit=None, filesystem=None,
-                 page_checksum_verification=False):
+                 page_checksum_verification=False, smallest_decimal_enabled=False):
 
         self._close_source = getattr(source, 'closed', True)
 
@@ -323,6 +326,7 @@ def __init__(self, source, *, metadata=None, common_metadata=None,
             thrift_string_size_limit=thrift_string_size_limit,
             thrift_container_size_limit=thrift_container_size_limit,
             page_checksum_verification=page_checksum_verification,
+            smallest_decimal_enabled=smallest_decimal_enabled,
         )
         self.common_metadata = common_metadata
         self._nested_paths_by_prefix = self._build_nested_paths()
@@ -1267,6 +1271,9 @@ class ParquetDataset:
     If True, verify the page checksum for each page read from the file.
 use_legacy_dataset : bool, optional
     Deprecated and has no effect from PyArrow version 15.0.0.
+smallest_decimal_enabled : bool, default False
+    If True, always convert to the smallest arrow decimal type based
+    on precision.
 
 Examples
 --------
@@ -1280,7 +1287,8 @@ def __init__(self, path_or_paths, filesystem=None, schema=None, *, filters=None,
                  decryption_properties=None, thrift_string_size_limit=None,
                  thrift_container_size_limit=None,
                  page_checksum_verification=False,
-                 use_legacy_dataset=None):
+                 use_legacy_dataset=None,
+                 smallest_decimal_enabled=False):
 
         if use_legacy_dataset is not None:
             warnings.warn(
@@ -1297,6 +1305,7 @@ def __init__(self, path_or_paths, filesystem=None, schema=None, *, filters=None,
             "thrift_string_size_limit": thrift_string_size_limit,
             "thrift_container_size_limit": thrift_container_size_limit,
             "page_checksum_verification": page_checksum_verification,
+            "smallest_decimal_enabled": smallest_decimal_enabled,
         }
         if buffer_size:
             read_options.update(use_buffered_stream=True,
@@ -1686,6 +1695,9 @@ def partitioning(self):
     sufficient for most Parquet files.
 page_checksum_verification : bool, default False
     If True, verify the checksum for each page read from the file.
+smallest_decimal_enabled : bool, default False
+    If True, always convert to the smallest arrow decimal type based
+    on precision.
 
 Returns
 -------
@@ -1781,7 +1793,8 @@ def read_table(source, *, columns=None, use_threads=True,
                coerce_int96_timestamp_unit=None,
                decryption_properties=None, thrift_string_size_limit=None,
                thrift_container_size_limit=None,
-               page_checksum_verification=False):
+               page_checksum_verification=False,
+               smallest_decimal_enabled=False):
 
     if use_legacy_dataset is not None:
         warnings.warn(
@@ -1806,6 +1819,7 @@ def read_table(source, *, columns=None, use_threads=True,
             thrift_string_size_limit=thrift_string_size_limit,
             thrift_container_size_limit=thrift_container_size_limit,
             page_checksum_verification=page_checksum_verification,
+            smallest_decimal_enabled=smallest_decimal_enabled,
         )
     except ImportError:
         # fall back on ParquetFile for simple cases when pyarrow.dataset
@@ -1838,6 +1852,7 @@ def read_table(source, *, columns=None, use_threads=True,
             thrift_string_size_limit=thrift_string_size_limit,
             thrift_container_size_limit=thrift_container_size_limit,
             page_checksum_verification=page_checksum_verification,
+            smallest_decimal_enabled=smallest_decimal_enabled,
         )
 
     return dataset.read(columns=columns, use_threads=use_threads,

python/pyarrow/tests/parquet/test_basic.py

@@ -362,6 +362,20 @@ def test_byte_stream_split():
                          use_dictionary=False)
 
 
+def test_smallest_decimal_enabled(tempdir):
+    arr1 = pa.array(list(map(Decimal, range(100))), type=pa.decimal32(5, 2))
+    arr2 = pa.array(list(map(Decimal, range(100))), type=pa.decimal64(16, 9))
+    arr3 = pa.array(list(map(Decimal, range(100))), type=pa.decimal128(22, 2))
+    arr4 = pa.array(list(map(Decimal, range(100))), type=pa.decimal256(48, 2))
+    data_decimal = [arr1, arr2, arr3, arr4]
+    table = pa.Table.from_arrays(data_decimal, names=['a', 'b', 'c', 'd'])
+
+    # Check with smallest_decimal_enabled
+    _check_roundtrip(table,
+                     expected=table,
+                     read_table_kwargs={"smallest_decimal_enabled": True})
+
+
 def test_store_decimal_as_integer(tempdir):
     arr_decimal_1_9 = pa.array(list(map(Decimal, range(100))),
                                type=pa.decimal128(5, 2))