Add coerce_types flag to parquet WriterProperties (apache#1938)

Author: getChan

parquet/src/file/properties.rs

@@ -53,6 +53,8 @@ pub const DEFAULT_BLOOM_FILTER_FPP: f64 = 0.05;
 pub const DEFAULT_BLOOM_FILTER_NDV: u64 = 1_000_000_u64;
 /// Default values for [`WriterProperties::statistics_truncate_length`]
 pub const DEFAULT_STATISTICS_TRUNCATE_LENGTH: Option<usize> = None;
+/// Default values for [`WriterProperties::coerce_types`]
+pub const DEFAULT_COERCE_TYPES: bool = false;
 
 /// Parquet writer version.
 ///
@@ -139,6 +141,7 @@ pub struct WriterProperties {
     sorting_columns: Option<Vec<SortingColumn>>,
     column_index_truncate_length: Option<usize>,
     statistics_truncate_length: Option<usize>,
+    coerce_types: bool,
 }
 
 impl Default for WriterProperties {
@@ -251,6 +254,13 @@ impl WriterProperties {
         self.statistics_truncate_length
     }
 
+    /// Returns `coerce_types` boolean
+    ///
+    /// `true` if type coercion enabled.
+    pub fn coerce_types(&self) -> bool {
+        self.coerce_types
+    }
+
     /// Returns encoding for a data page, when dictionary encoding is enabled.
     /// This is not configurable.
     #[inline]
@@ -345,6 +355,7 @@ pub struct WriterPropertiesBuilder {
     sorting_columns: Option<Vec<SortingColumn>>,
     column_index_truncate_length: Option<usize>,
     statistics_truncate_length: Option<usize>,
+    coerce_types: bool,
 }
 
 impl WriterPropertiesBuilder {
@@ -364,6 +375,7 @@ impl WriterPropertiesBuilder {
             sorting_columns: None,
             column_index_truncate_length: DEFAULT_COLUMN_INDEX_TRUNCATE_LENGTH,
             statistics_truncate_length: DEFAULT_STATISTICS_TRUNCATE_LENGTH,
+            coerce_types: DEFAULT_COERCE_TYPES,
         }
     }
 
@@ -383,6 +395,7 @@ impl WriterPropertiesBuilder {
             sorting_columns: self.sorting_columns,
             column_index_truncate_length: self.column_index_truncate_length,
             statistics_truncate_length: self.statistics_truncate_length,
+            coerce_types: self.coerce_types,
         }
     }
 
@@ -667,6 +680,13 @@ impl WriterPropertiesBuilder {
         self.statistics_truncate_length = max_length;
         self
     }
+
+    /// Sets flag to enable/disable type coercion.
+    /// Takes precedence over globally defined settings.
+    pub fn set_coerce_types(mut self, coerce_types: bool) -> Self {
+        self.coerce_types = coerce_types;
+        self
+    }
 }
 
 /// Controls the level of statistics to be computed by the writer