feat: change default behavior for Parquet PageEncodingStats to bitmask (#9051)

# Which issue does this PR close?

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- Closes #8859 

# Rationale for this change

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in the issue then this section is not needed.
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your changes and offer better suggestions for fixes.
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> Currently the default behavior is to parse the full vector of encoding
stats, but given the limited use of this information we should instead
default to the more concise and performant bitmask.

# What changes are included in this PR?

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is sometimes worth providing a summary of the individual changes in this
PR.
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- Implement `Default` for `ParquetMetaDataOptions` with
`encoding_stats_as_mask: true`
- Update Thrift decoding logic to default to bitmask even if options are
missing
- Update documentation to reflect the new default behavior
- Update existing tests to maintain coverage for full statistics
- Add new tests to verify default behavior and full stats option

# Are these changes tested?

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Yes

# Are there any user-facing changes?

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Yes

Author: WaterWhisperer

parquet/benches/metadata.rs

@@ -21,7 +21,7 @@ use std::sync::Arc;
 use parquet::basic::{Encoding, PageType, Type as PhysicalType};
 use parquet::file::metadata::{
     ColumnChunkMetaData, FileMetaData, PageEncodingStats, ParquetMetaData, ParquetMetaDataOptions,
-    ParquetMetaDataReader, ParquetMetaDataWriter, ParquetStatisticsPolicy, RowGroupMetaData,
+    ParquetMetaDataReader, ParquetMetaDataWriter, RowGroupMetaData,
 };
 use parquet::file::statistics::Statistics;
 use parquet::file::writer::TrackedWrite;
@@ -164,26 +164,17 @@ fn criterion_benchmark(c: &mut Criterion) {
         })
     });
 
-    let schema = ParquetMetaDataReader::decode_schema(&meta_data).unwrap();
-    let options = ParquetMetaDataOptions::new().with_schema(schema);
-    c.bench_function("decode metadata with schema", |b| {
-        b.iter(|| {
-            ParquetMetaDataReader::decode_metadata_with_options(&meta_data, Some(&options))
-                .unwrap();
-        })
-    });
-
-    let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(true);
-    c.bench_function("decode metadata with stats mask", |b| {
+    let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
+    c.bench_function("decode metadata (full stats)", |b| {
         b.iter(|| {
             ParquetMetaDataReader::decode_metadata_with_options(&meta_data, Some(&options))
                 .unwrap();
         })
     });
 
-    let options =
-        ParquetMetaDataOptions::new().with_encoding_stats_policy(ParquetStatisticsPolicy::SkipAll);
-    c.bench_function("decode metadata with skip PES", |b| {
+    let schema = ParquetMetaDataReader::decode_schema(&meta_data).unwrap();
+    let options = ParquetMetaDataOptions::new().with_schema(schema);
+    c.bench_function("decode metadata with schema", |b| {
         b.iter(|| {
             ParquetMetaDataReader::decode_metadata_with_options(&meta_data, Some(&options))
                 .unwrap();
@@ -197,24 +188,16 @@ fn criterion_benchmark(c: &mut Criterion) {
         })
     });
 
-    let schema = ParquetMetaDataReader::decode_schema(&buf).unwrap();
-    let options = ParquetMetaDataOptions::new().with_schema(schema);
-    c.bench_function("decode metadata (wide) with schema", |b| {
+    let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
+    c.bench_function("decode metadata (wide) (full stats)", |b| {
         b.iter(|| {
             ParquetMetaDataReader::decode_metadata_with_options(&buf, Some(&options)).unwrap();
         })
     });
 
-    let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(true);
-    c.bench_function("decode metadata (wide) with stats mask", |b| {
-        b.iter(|| {
-            ParquetMetaDataReader::decode_metadata_with_options(&buf, Some(&options)).unwrap();
-        })
-    });
-
-    let options =
-        ParquetMetaDataOptions::new().with_encoding_stats_policy(ParquetStatisticsPolicy::SkipAll);
-    c.bench_function("decode metadata (wide) with skip PES", |b| {
+    let schema = ParquetMetaDataReader::decode_schema(&buf).unwrap();
+    let options = ParquetMetaDataOptions::new().with_schema(schema);
+    c.bench_function("decode metadata (wide) with schema", |b| {
         b.iter(|| {
             ParquetMetaDataReader::decode_metadata_with_options(&buf, Some(&options)).unwrap();
         })

parquet/src/arrow/arrow_writer/mod.rs

@@ -4480,7 +4480,10 @@ mod tests {
             .unwrap();
 
         // check that the read metadata is also correct
-        let options = ReadOptionsBuilder::new().with_page_index().build();
+        let options = ReadOptionsBuilder::new()
+            .with_page_index()
+            .with_encoding_stats_as_mask(false)
+            .build();
         let reader = SerializedFileReader::new_with_options(file, options).unwrap();
 
         let rowgroup = reader.get_row_group(0).expect("row group missing");

parquet/src/arrow/mod.rs

@@ -494,7 +494,9 @@ pub fn parquet_column<'a>(
 #[cfg(test)]
 mod test {
     use crate::arrow::ArrowWriter;
-    use crate::file::metadata::{ParquetMetaData, ParquetMetaDataReader, ParquetMetaDataWriter};
+    use crate::file::metadata::{
+        ParquetMetaData, ParquetMetaDataOptions, ParquetMetaDataReader, ParquetMetaDataWriter,
+    };
     use crate::file::properties::{EnabledStatistics, WriterProperties};
     use crate::schema::parser::parse_message_type;
     use crate::schema::types::SchemaDescriptor;
@@ -511,13 +513,17 @@ mod test {
         let parquet_bytes = create_parquet_file();
 
         // read the metadata from the file WITHOUT the page index structures
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
         let original_metadata = ParquetMetaDataReader::new()
+            .with_metadata_options(Some(options))
             .parse_and_finish(&parquet_bytes)
             .unwrap();
 
         // this should error because the page indexes are not present, but have offsets specified
         let metadata_bytes = metadata_to_bytes(&original_metadata);
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
         let err = ParquetMetaDataReader::new()
+            .with_metadata_options(Some(options))
             .with_page_indexes(true) // there are no page indexes in the metadata
             .parse_and_finish(&metadata_bytes)
             .err()
@@ -533,7 +539,9 @@ mod test {
         let parquet_bytes = create_parquet_file();
 
         // read the metadata from the file
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
         let original_metadata = ParquetMetaDataReader::new()
+            .with_metadata_options(Some(options))
             .parse_and_finish(&parquet_bytes)
             .unwrap();
 
@@ -545,7 +553,9 @@ mod test {
             "metadata is subset of parquet"
         );
 
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
         let roundtrip_metadata = ParquetMetaDataReader::new()
+            .with_metadata_options(Some(options))
             .parse_and_finish(&metadata_bytes)
             .unwrap();
 
@@ -559,14 +569,18 @@ mod test {
 
         // read the metadata from the file including the page index structures
         // (which are stored elsewhere in the footer)
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
         let original_metadata = ParquetMetaDataReader::new()
+            .with_metadata_options(Some(options))
             .with_page_indexes(true)
             .parse_and_finish(&parquet_bytes)
             .unwrap();
 
         // read metadata back from the serialized bytes and ensure it is the same
         let metadata_bytes = metadata_to_bytes(&original_metadata);
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
         let roundtrip_metadata = ParquetMetaDataReader::new()
+            .with_metadata_options(Some(options))
             .with_page_indexes(true)
             .parse_and_finish(&metadata_bytes)
             .unwrap();

parquet/src/file/metadata/mod.rs

@@ -1062,6 +1062,10 @@ impl ColumnChunkMetaData {
 
     /// Returns the page encoding statistics, or `None` if no page encoding statistics
     /// are available (or they were converted to a mask).
+    ///
+    /// Note: By default, this crate converts page encoding statistics to a mask for performance
+    /// reasons. To get the full statistics, you must set [`ParquetMetaDataOptions::with_encoding_stats_as_mask`]
+    /// to `false`.
     pub fn page_encoding_stats(&self) -> Option<&Vec<PageEncodingStats>> {
         match self.encoding_stats.as_ref() {
             Some(ParquetPageEncodingStats::Full(stats)) => Some(stats),
@@ -1072,6 +1076,8 @@ impl ColumnChunkMetaData {
     /// Returns the page encoding statistics reduced to a bitmask, or `None` if statistics are
     /// not available (or they were left in their original form).
     ///
+    /// Note: This is the default behavior for this crate.
+    ///
     /// The [`PageEncodingStats`] struct was added to the Parquet specification specifically to
     /// enable fast determination of whether all pages in a column chunk are dictionary encoded
     /// (see <https://github.com/apache/parquet-format/pull/16>).
@@ -1667,7 +1673,9 @@ impl OffsetIndexBuilder {
 mod tests {
     use super::*;
     use crate::basic::{PageType, SortOrder};
-    use crate::file::metadata::thrift::tests::{read_column_chunk, read_row_group};
+    use crate::file::metadata::thrift::tests::{
+        read_column_chunk, read_column_chunk_with_options, read_row_group,
+    };
 
     #[test]
     fn test_row_group_metadata_thrift_conversion() {
@@ -1822,7 +1830,72 @@ mod tests {
         let mut buf = Vec::new();
         let mut writer = ThriftCompactOutputProtocol::new(&mut buf);
         col_metadata.write_thrift(&mut writer).unwrap();
-        let col_chunk_res = read_column_chunk(&mut buf, column_descr).unwrap();
+        let col_chunk_res = read_column_chunk(&mut buf, column_descr.clone()).unwrap();
+
+        let expected_metadata = ColumnChunkMetaData::builder(column_descr)
+            .set_encodings_mask(EncodingMask::new_from_encodings(
+                [Encoding::PLAIN, Encoding::RLE].iter(),
+            ))
+            .set_file_path("file_path".to_owned())
+            .set_num_values(1000)
+            .set_compression(Compression::SNAPPY)
+            .set_total_compressed_size(2000)
+            .set_total_uncompressed_size(3000)
+            .set_data_page_offset(4000)
+            .set_dictionary_page_offset(Some(5000))
+            .set_page_encoding_stats_mask(EncodingMask::new_from_encodings(
+                [Encoding::PLAIN, Encoding::RLE].iter(),
+            ))
+            .set_bloom_filter_offset(Some(6000))
+            .set_bloom_filter_length(Some(25))
+            .set_offset_index_offset(Some(7000))
+            .set_offset_index_length(Some(25))
+            .set_column_index_offset(Some(8000))
+            .set_column_index_length(Some(25))
+            .set_unencoded_byte_array_data_bytes(Some(2000))
+            .set_repetition_level_histogram(Some(LevelHistogram::from(vec![100, 100])))
+            .set_definition_level_histogram(Some(LevelHistogram::from(vec![0, 200])))
+            .build()
+            .unwrap();
+
+        assert_eq!(col_chunk_res, expected_metadata);
+    }
+
+    #[test]
+    fn test_column_chunk_metadata_thrift_conversion_full_stats() {
+        let column_descr = get_test_schema_descr().column(0);
+        let stats = vec![
+            PageEncodingStats {
+                page_type: PageType::DATA_PAGE,
+                encoding: Encoding::PLAIN,
+                count: 3,
+            },
+            PageEncodingStats {
+                page_type: PageType::DATA_PAGE,
+                encoding: Encoding::RLE,
+                count: 5,
+            },
+        ];
+        let col_metadata = ColumnChunkMetaData::builder(column_descr.clone())
+            .set_encodings_mask(EncodingMask::new_from_encodings(
+                [Encoding::PLAIN, Encoding::RLE].iter(),
+            ))
+            .set_num_values(1000)
+            .set_compression(Compression::SNAPPY)
+            .set_total_compressed_size(2000)
+            .set_total_uncompressed_size(3000)
+            .set_data_page_offset(4000)
+            .set_page_encoding_stats(stats)
+            .build()
+            .unwrap();
+
+        let mut buf = Vec::new();
+        let mut writer = ThriftCompactOutputProtocol::new(&mut buf);
+        col_metadata.write_thrift(&mut writer).unwrap();
+
+        let options = ParquetMetaDataOptions::new().with_encoding_stats_as_mask(false);
+        let col_chunk_res =
+            read_column_chunk_with_options(&mut buf, column_descr, Some(&options)).unwrap();
 
         assert_eq!(col_chunk_res, col_metadata);
     }

parquet/src/file/metadata/options.rs

@@ -87,13 +87,23 @@ impl ParquetStatisticsPolicy {
 /// [`ParquetMetaData`]: crate::file::metadata::ParquetMetaData
 /// [`ParquetMetaDataReader`]: crate::file::metadata::ParquetMetaDataReader
 /// [`ParquetMetaDataPushDecoder`]: crate::file::metadata::ParquetMetaDataPushDecoder
-#[derive(Default, Debug, Clone)]
+#[derive(Debug, Clone)]
 pub struct ParquetMetaDataOptions {
     schema_descr: Option<SchemaDescPtr>,
     encoding_stats_as_mask: bool,
     encoding_stats_policy: ParquetStatisticsPolicy,
 }
 
+impl Default for ParquetMetaDataOptions {
+    fn default() -> Self {
+        Self {
+            schema_descr: None,
+            encoding_stats_as_mask: true,
+            encoding_stats_policy: ParquetStatisticsPolicy::KeepAll,
+        }
+    }
+}
+
 impl ParquetMetaDataOptions {
     /// Return a new default [`ParquetMetaDataOptions`].
     pub fn new() -> Self {
@@ -118,7 +128,7 @@ impl ParquetMetaDataOptions {
     }
 
     /// Returns whether to present the [`encoding_stats`] field of the Parquet `ColumnMetaData`
-    /// as a bitmask (defaults to `false`).
+    /// as a bitmask (defaults to `true`).
     ///
     /// See [`ColumnChunkMetaData::page_encoding_stats_mask`] for an explanation of why this
     /// might be desirable.
@@ -193,6 +203,12 @@ mod tests {
     };
     use std::{io::Read, sync::Arc};
 
+    #[test]
+    fn test_options_default() {
+        let options = ParquetMetaDataOptions::default();
+        assert!(options.encoding_stats_as_mask());
+    }
+
     #[test]
     fn test_provide_schema() {
         let mut buf: Vec<u8> = Vec::new();

parquet/src/file/metadata/thrift/mod.rs

@@ -410,7 +410,7 @@ fn read_column_metadata<'a>(
     let mut seen_mask = 0u16;
 
     let mut skip_pes = false;
-    let mut pes_mask = false;
+    let mut pes_mask = true;
 
     if let Some(opts) = options {
         skip_pes = opts.skip_encoding_stats(col_index);
@@ -1704,7 +1704,7 @@ write_thrift_field!(RustBoundingBox, FieldType::Struct);
 pub(crate) mod tests {
     use crate::errors::Result;
     use crate::file::metadata::thrift::{BoundingBox, SchemaElement, write_schema};
-    use crate::file::metadata::{ColumnChunkMetaData, RowGroupMetaData};
+    use crate::file::metadata::{ColumnChunkMetaData, ParquetMetaDataOptions, RowGroupMetaData};
     use crate::parquet_thrift::tests::test_roundtrip;
     use crate::parquet_thrift::{
         ElementType, ThriftCompactOutputProtocol, ThriftSliceInputProtocol, read_thrift_vec,
@@ -1726,9 +1726,17 @@ pub(crate) mod tests {
     pub(crate) fn read_column_chunk(
         buf: &mut [u8],
         column_descr: Arc<ColumnDescriptor>,
+    ) -> Result<ColumnChunkMetaData> {
+        read_column_chunk_with_options(buf, column_descr, None)
+    }
+
+    pub(crate) fn read_column_chunk_with_options(
+        buf: &mut [u8],
+        column_descr: Arc<ColumnDescriptor>,
+        options: Option<&ParquetMetaDataOptions>,
     ) -> Result<ColumnChunkMetaData> {
         let mut reader = ThriftSliceInputProtocol::new(buf);
-        crate::file::metadata::thrift::read_column_chunk(&mut reader, &column_descr, 0, None)
+        crate::file::metadata::thrift::read_column_chunk(&mut reader, &column_descr, 0, options)
     }
 
     pub(crate) fn roundtrip_schema(schema: TypePtr) -> Result<TypePtr> {

parquet/src/file/serialized_reader.rs

@@ -1855,7 +1855,10 @@ mod tests {
     fn test_file_reader_optional_metadata() {
         // file with optional metadata: bloom filters, encoding stats, column index and offset index.
         let file = get_test_file("data_index_bloom_encoding_stats.parquet");
-        let file_reader = Arc::new(SerializedFileReader::new(file).unwrap());
+        let options = ReadOptionsBuilder::new()
+            .with_encoding_stats_as_mask(false)
+            .build();
+        let file_reader = Arc::new(SerializedFileReader::new_with_options(file, options).unwrap());
 
         let row_group_metadata = file_reader.metadata.row_group(0);
         let col0_metadata = row_group_metadata.column(0);