Function arrow2::io::parquet::read::indexes::read_filtered_pages

pub fn read_filtered_pages<R: Read + Seek, F: Fn(&[FieldPageStatistics], &[Vec<Vec<Interval>>]) -> Vec<Interval>>(
    reader: &mut R,
    row_group: &RowGroupMetaData,
    fields: &[Field],
    predicate: F
) -> Result<Vec<Vec<Vec<FilteredPage>>>, Error>

Available on crate feature io_parquet only.

Reads all page locations and index locations (IO-bounded) and uses predicate to compute the set of FilteredPage that fulfill the predicate.

The non-trivial argument of this function is predicate, that controls which pages are selected. Its signature contains 2 arguments:

• 0th argument (indexes): contains one ColumnPageStatistics (page statistics) per field. Use it to evaluate the predicate against
• 1th argument (intervals): contains one Vec<Vec<Interval>> (row positions) per field. For each field, the outermost vector corresponds to each parquet column: a primitive field contains 1 column, a struct field with 2 primitive fields contain 2 columns. The inner Vec<Interval> contains one Interval per page: its length equals the length of ColumnPageStatistics. It returns a single Vec<Interval> denoting the set of intervals that the predicate selects (over all columns).

This returns one item per field. For each field, there is one item per column (for non-nested types it returns one column) and finally Vec<FilteredPage>, that corresponds to the set of selected pages.