parquet/file/page_index/
index_reader.rs

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License.  You may obtain a copy of the License at
//
//   http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

//! Support for reading [`Index`] and [`PageLocation`] from parquet metadata.

use crate::basic::Type;
use crate::data_type::Int96;
use crate::errors::ParquetError;
use crate::file::metadata::ColumnChunkMetaData;
use crate::file::page_index::index::{Index, NativeIndex};
use crate::file::page_index::offset_index::OffsetIndexMetaData;
use crate::file::reader::ChunkReader;
use crate::format::{ColumnIndex, OffsetIndex, PageLocation};
use crate::thrift::{TCompactSliceInputProtocol, TSerializable};
use std::ops::Range;

/// Computes the covering range of two optional ranges
///
/// For example `acc_range(Some(7..9), Some(1..3)) = Some(1..9)`
pub(crate) fn acc_range(a: Option<Range<usize>>, b: Option<Range<usize>>) -> Option<Range<usize>> {
    match (a, b) {
        (Some(a), Some(b)) => Some(a.start.min(b.start)..a.end.max(b.end)),
        (None, x) | (x, None) => x,
    }
}

/// Reads per-column [`Index`] for all columns of a row group by
/// decoding [`ColumnIndex`] .
///
/// Returns a vector of `index[column_number]`.
///
/// Returns an empty vector if this row group does not contain a
/// [`ColumnIndex`].
///
/// See [Page Index Documentation] for more details.
///
/// [Page Index Documentation]: https://github.com/apache/parquet-format/blob/master/PageIndex.md
pub fn read_columns_indexes<R: ChunkReader>(
    reader: &R,
    chunks: &[ColumnChunkMetaData],
) -> Result<Vec<Index>, ParquetError> {
    let fetch = chunks
        .iter()
        .fold(None, |range, c| acc_range(range, c.column_index_range()));

    let fetch = match fetch {
        Some(r) => r,
        None => return Ok(vec![Index::NONE; chunks.len()]),
    };

    let bytes = reader.get_bytes(fetch.start as _, fetch.end - fetch.start)?;
    let get = |r: Range<usize>| &bytes[(r.start - fetch.start)..(r.end - fetch.start)];

    chunks
        .iter()
        .map(|c| match c.column_index_range() {
            Some(r) => decode_column_index(get(r), c.column_type()),
            None => Ok(Index::NONE),
        })
        .collect()
}

/// Reads [`OffsetIndex`],  per-page [`PageLocation`] for all columns of a row
/// group.
///
/// Returns a vector of `location[column_number][page_number]`
///
/// Return an empty vector if this row group does not contain an
/// [`OffsetIndex]`.
///
/// See [Page Index Documentation] for more details.
///
/// [Page Index Documentation]: https://github.com/apache/parquet-format/blob/master/PageIndex.md
#[deprecated(since = "53.0.0", note = "Use read_offset_indexes")]
pub fn read_pages_locations<R: ChunkReader>(
    reader: &R,
    chunks: &[ColumnChunkMetaData],
) -> Result<Vec<Vec<PageLocation>>, ParquetError> {
    let fetch = chunks
        .iter()
        .fold(None, |range, c| acc_range(range, c.offset_index_range()));

    let fetch = match fetch {
        Some(r) => r,
        None => return Ok(vec![]),
    };

    let bytes = reader.get_bytes(fetch.start as _, fetch.end - fetch.start)?;
    let get = |r: Range<usize>| &bytes[(r.start - fetch.start)..(r.end - fetch.start)];

    chunks
        .iter()
        .map(|c| match c.offset_index_range() {
            Some(r) => decode_page_locations(get(r)),
            None => Err(general_err!("missing offset index")),
        })
        .collect()
}

/// Reads per-column [`OffsetIndexMetaData`] for all columns of a row group by
/// decoding [`OffsetIndex`] .
///
/// Returns a vector of `offset_index[column_number]`.
///
/// Returns an empty vector if this row group does not contain an
/// [`OffsetIndex`].
///
/// See [Page Index Documentation] for more details.
///
/// [Page Index Documentation]: https://github.com/apache/parquet-format/blob/master/PageIndex.md
pub fn read_offset_indexes<R: ChunkReader>(
    reader: &R,
    chunks: &[ColumnChunkMetaData],
) -> Result<Vec<OffsetIndexMetaData>, ParquetError> {
    let fetch = chunks
        .iter()
        .fold(None, |range, c| acc_range(range, c.offset_index_range()));

    let fetch = match fetch {
        Some(r) => r,
        None => return Ok(vec![]),
    };

    let bytes = reader.get_bytes(fetch.start as _, fetch.end - fetch.start)?;
    let get = |r: Range<usize>| &bytes[(r.start - fetch.start)..(r.end - fetch.start)];

    chunks
        .iter()
        .map(|c| match c.offset_index_range() {
            Some(r) => decode_offset_index(get(r)),
            None => Err(general_err!("missing offset index")),
        })
        .collect()
}

pub(crate) fn decode_offset_index(data: &[u8]) -> Result<OffsetIndexMetaData, ParquetError> {
    let mut prot = TCompactSliceInputProtocol::new(data);
    let offset = OffsetIndex::read_from_in_protocol(&mut prot)?;
    OffsetIndexMetaData::try_new(offset)
}

pub(crate) fn decode_page_locations(data: &[u8]) -> Result<Vec<PageLocation>, ParquetError> {
    let mut prot = TCompactSliceInputProtocol::new(data);
    let offset = OffsetIndex::read_from_in_protocol(&mut prot)?;
    Ok(offset.page_locations)
}

pub(crate) fn decode_column_index(data: &[u8], column_type: Type) -> Result<Index, ParquetError> {
    let mut prot = TCompactSliceInputProtocol::new(data);

    let index = ColumnIndex::read_from_in_protocol(&mut prot)?;

    let index = match column_type {
        Type::BOOLEAN => Index::BOOLEAN(NativeIndex::<bool>::try_new(index)?),
        Type::INT32 => Index::INT32(NativeIndex::<i32>::try_new(index)?),
        Type::INT64 => Index::INT64(NativeIndex::<i64>::try_new(index)?),
        Type::INT96 => Index::INT96(NativeIndex::<Int96>::try_new(index)?),
        Type::FLOAT => Index::FLOAT(NativeIndex::<f32>::try_new(index)?),
        Type::DOUBLE => Index::DOUBLE(NativeIndex::<f64>::try_new(index)?),
        Type::BYTE_ARRAY => Index::BYTE_ARRAY(NativeIndex::try_new(index)?),
        Type::FIXED_LEN_BYTE_ARRAY => Index::FIXED_LEN_BYTE_ARRAY(NativeIndex::try_new(index)?),
    };

    Ok(index)
}