[GitHub] [arrow-rs] yjshen commented on a change in pull request #1389: Introduce `ReadOptions` with builder API, filter row groups that satisfy all filters, and enable filter row groups by range.

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yjshen commented on a change in pull request #1389:
URL: https://github.com/apache/arrow-rs/pull/1389#discussion_r820164755



##########
File path: parquet/src/file/serialized_reader.rs
##########
@@ -127,6 +127,56 @@ pub struct SerializedFileReader<R: ChunkReader> {
     metadata: ParquetMetaData,
 }
 
+/// A builder for [`ReadOptions`].
+/// For the predicates that are added to the builder,
+/// they will be chained using 'AND' to filter the row groups.
+pub struct ReadOptionsBuilder {
+    predicates: Vec<Box<dyn FnMut(&RowGroupMetaData, usize) -> bool>>,
+}
+
+impl ReadOptionsBuilder {
+    /// New builder
+    pub fn new() -> Self {
+        ReadOptionsBuilder { predicates: vec![] }
+    }
+
+    /// Add a predicate on row group metadata to the reading option,
+    /// Filter only row groups that match the predicate criteria
+    pub fn with_predicate(
+        mut self,
+        predicate: Box<dyn FnMut(&RowGroupMetaData, usize) -> bool>,
+    ) -> Self {
+        self.predicates.push(predicate);
+        self
+    }
+
+    /// Add a range predicate on filtering row groups if their midpoints are within the range

Review comment:
       Thanks, this is important. I've updated the doc.




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