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Skiprefactoring skipabsolute (#831)

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Simplification of the way we handle positions.
This commit is contained in:
Paul Masurel
2020-05-25 09:51:23 +09:00
committed by GitHub
parent b974e7ce34
commit 7275ebdf3c
11 changed files with 847 additions and 800 deletions
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6
src/core/inverted_index_reader.rs
View File

@@ -7,7 +7,6 @@ use crate::schema::FieldType;
use crate::schema::IndexRecordOption;
use crate::schema::Term;
use crate::termdict::TermDictionary;
use owned_read::OwnedRead;
/// The inverted index reader is in charge of accessing
/// the inverted index associated to a specific field.
@@ -97,8 +96,7 @@ impl InvertedIndexReader {
let offset = term_info.postings_offset as usize;
let end_source = self.postings_source.len();
let postings_slice = self.postings_source.slice(offset, end_source);
let postings_reader = OwnedRead::new(postings_slice);
block_postings.reset(term_info.doc_freq, postings_reader);
block_postings.reset(term_info.doc_freq, postings_slice);
}
/// Returns a block postings given a `Term`.
@@ -127,7 +125,7 @@ impl InvertedIndexReader {
let postings_data = self.postings_source.slice_from(offset);
BlockSegmentPostings::from_data(
term_info.doc_freq,
OwnedRead::new(postings_data),
postings_data,
self.record_option,
requested_option,
)

89
src/positions/mod.rs
View File

@@ -37,9 +37,9 @@ const LONG_SKIP_INTERVAL: u64 = (LONG_SKIP_IN_BLOCKS * COMPRESSION_BLOCK_SIZE) a
#[cfg(test)]
pub mod tests {
use super::{PositionReader, PositionSerializer};
use super::PositionSerializer;
use crate::directory::ReadOnlySource;
use crate::positions::COMPRESSION_BLOCK_SIZE;
use crate::positions::reader::PositionReader;
use std::iter;
fn create_stream_buffer(vals: &[u32]) -> (ReadOnlySource, ReadOnlySource) {
@@ -68,7 +68,7 @@ pub mod tests {
let mut position_reader = PositionReader::new(stream, skip, 0u64);
for &n in &[1, 10, 127, 128, 130, 312] {
let mut v = vec![0u32; n];
position_reader.read(&mut v[..n]);
position_reader.read(0, &mut v[..]);
for i in 0..n {
assert_eq!(v[i], i as u32);
}
@@ -76,19 +76,19 @@ pub mod tests {
}
#[test]
fn test_position_skip() {
let v: Vec<u32> = (0..1_000).collect();
fn test_position_read_with_offset() {
let v: Vec<u32> = (0..1000).collect();
let (stream, skip) = create_stream_buffer(&v[..]);
assert_eq!(skip.len(), 12);
assert_eq!(stream.len(), 1168);
let mut position_reader = PositionReader::new(stream, skip, 0u64);
position_reader.skip(10);
for &n in &[10, 127, COMPRESSION_BLOCK_SIZE, 130, 312] {
let mut v = vec![0u32; n];
position_reader.read(&mut v[..n]);
for i in 0..n {
assert_eq!(v[i], 10u32 + i as u32);
for &offset in &[1u64, 10u64, 127u64, 128u64, 130u64, 312u64] {
for &len in &[1, 10, 130, 500] {
let mut v = vec![0u32; len];
position_reader.read(offset, &mut v[..]);
for i in 0..len {
assert_eq!(v[i], i as u32 + offset as u32);
}
}
}
}
@@ -103,11 +103,12 @@ pub mod tests {
let mut position_reader = PositionReader::new(stream, skip, 0u64);
let mut buf = [0u32; 7];
let mut c = 0;
let mut offset = 0;
for _ in 0..100 {
position_reader.read(&mut buf);
position_reader.read(&mut buf);
position_reader.skip(4);
position_reader.skip(3);
position_reader.read(offset, &mut buf);
position_reader.read(offset, &mut buf);
offset += 7;
for &el in &buf {
assert_eq!(c, el);
c += 1;
@@ -115,6 +116,58 @@ pub mod tests {
}
}
#[test]
fn test_position_reread_anchor_different_than_block() {
let v: Vec<u32> = (0..2_000_000).collect();
let (stream, skip) = create_stream_buffer(&v[..]);
assert_eq!(skip.len(), 15_749);
assert_eq!(stream.len(), 4_987_872);
let mut position_reader = PositionReader::new(stream.clone(), skip.clone(), 0);
let mut buf = [0u32; 256];
position_reader.read(128, &mut buf);
for i in 0..256 {
assert_eq!(buf[i], (128 + i) as u32);
}
position_reader.read(128, &mut buf);
for i in 0..256 {
assert_eq!(buf[i], (128 + i) as u32);
}
}
#[test]
#[should_panic(expected = "offset arguments should be increasing.")]
fn test_position_panic_if_called_previous_anchor() {
let v: Vec<u32> = (0..2_000_000).collect();
let (stream, skip) = create_stream_buffer(&v[..]);
assert_eq!(skip.len(), 15_749);
assert_eq!(stream.len(), 4_987_872);
let mut buf = [0u32; 1];
let mut position_reader = PositionReader::new(stream.clone(), skip.clone(), 200_000);
position_reader.read(230, &mut buf);
position_reader.read(9, &mut buf);
}
#[test]
fn test_positions_bug() {
let mut v: Vec<u32> = vec![];
for i in 1..200 {
for j in 0..i {
v.push(j);
}
}
let (stream, skip) = create_stream_buffer(&v[..]);
let mut buf = Vec::new();
let mut position_reader = PositionReader::new(stream.clone(), skip.clone(), 0);
let mut offset = 0;
for i in 1..24 {
buf.resize(i, 0);
position_reader.read(offset, &mut buf[..]);
offset += i as u64;
let r: Vec<u32> = (0..i).map(|el| el as u32).collect();
assert_eq!(buf, &r[..]);
}
}
#[test]
fn test_position_long_skip_const() {
const CONST_VAL: u32 = 9u32;
@@ -124,7 +177,7 @@ pub mod tests {
assert_eq!(stream.len(), 1_000_000);
let mut position_reader = PositionReader::new(stream, skip, 128 * 1024);
let mut buf = [0u32; 1];
position_reader.read(&mut buf);
position_reader.read(0, &mut buf);
assert_eq!(buf[0], CONST_VAL);
}
@@ -143,7 +196,7 @@ pub mod tests {
] {
let mut position_reader = PositionReader::new(stream.clone(), skip.clone(), offset);
let mut buf = [0u32; 1];
position_reader.read(&mut buf);
position_reader.read(0, &mut buf);
assert_eq!(buf[0], offset as u32);
}
}

168
src/positions/reader.rs
View File

@@ -3,7 +3,6 @@ use crate::directory::ReadOnlySource;
use crate::positions::COMPRESSION_BLOCK_SIZE;
use crate::positions::LONG_SKIP_INTERVAL;
use crate::positions::LONG_SKIP_IN_BLOCKS;
use crate::postings::compression::compressed_block_size;
/// Positions works as a long sequence of compressed block.
/// All terms are chained one after the other.
///
@@ -62,22 +61,20 @@ impl Positions {
fn reader(&self, offset: u64) -> PositionReader {
let long_skip_id = (offset / LONG_SKIP_INTERVAL) as usize;
let small_skip = (offset % LONG_SKIP_INTERVAL) as usize;
let offset_num_bytes: u64 = self.long_skip(long_skip_id);
let mut position_read = OwnedRead::new(self.position_source.clone());
position_read.advance(offset_num_bytes as usize);
let mut skip_read = OwnedRead::new(self.skip_source.clone());
skip_read.advance(long_skip_id * LONG_SKIP_IN_BLOCKS);
let mut position_reader = PositionReader {
PositionReader {
bit_packer: self.bit_packer,
skip_read,
position_read,
inner_offset: 0,
buffer: Box::new([0u32; 128]),
ahead: None,
};
position_reader.skip(small_skip);
position_reader
block_offset: std::i64::MAX as u64,
anchor_offset: (long_skip_id as u64) * LONG_SKIP_INTERVAL,
abs_offset: offset,
}
}
}
@@ -85,51 +82,12 @@ pub struct PositionReader {
skip_read: OwnedRead,
position_read: OwnedRead,
bit_packer: BitPacker4x,
inner_offset: usize,
buffer: Box<[u32; 128]>,
ahead: Option<usize>, // if None, no block is loaded.
// if Some(num_blocks), the block currently loaded is num_blocks ahead
// of the block of the next int to read.
}
buffer: Box<[u32; COMPRESSION_BLOCK_SIZE]>,
// `ahead` represents the offset of the block currently loaded
// compared to the cursor of the actual stream.
//
// By contract, when this function is called, the current block has to be
// decompressed.
//
// If the requested number of els ends exactly at a given block, the next
// block is not decompressed.
fn read_impl(
bit_packer: BitPacker4x,
mut position: &[u8],
buffer: &mut [u32; 128],
mut inner_offset: usize,
num_bits: &[u8],
output: &mut [u32],
) -> usize {
let mut output_start = 0;
let mut output_len = output.len();
let mut ahead = 0;
loop {
let available_len = COMPRESSION_BLOCK_SIZE - inner_offset;
// We have enough elements in the current block.
// Let's copy the requested elements in the output buffer,
// and return.
if output_len <= available_len {
output[output_start..].copy_from_slice(&buffer[inner_offset..][..output_len]);
return ahead;
}
output[output_start..][..available_len].copy_from_slice(&buffer[inner_offset..]);
output_len -= available_len;
output_start += available_len;
inner_offset = 0;
let num_bits = num_bits[ahead];
bit_packer.decompress(position, &mut buffer[..], num_bits);
let block_len = compressed_block_size(num_bits);
position = &position[block_len..];
ahead += 1;
}
block_offset: u64,
anchor_offset: u64,
abs_offset: u64,
}
impl PositionReader {
@@ -141,57 +99,65 @@ impl PositionReader {
Positions::new(position_source, skip_source).reader(offset)
}
/// Fills a buffer with the next `output.len()` integers.
/// This does not consume / advance the stream.
pub fn read(&mut self, output: &mut [u32]) {
let skip_data = self.skip_read.as_ref();
let position_data = self.position_read.as_ref();
let num_bits = self.skip_read.get(0);
if self.ahead != Some(0) {
// the block currently available is not the block
// for the current position
fn advance_num_blocks(&mut self, num_blocks: usize) {
let num_bits: usize = self.skip_read.as_ref()[..num_blocks]
.iter()
.cloned()
.map(|num_bits| num_bits as usize)
.sum();
let num_bytes_to_skip = num_bits * COMPRESSION_BLOCK_SIZE / 8;
self.skip_read.advance(num_blocks as usize);
self.position_read.advance(num_bytes_to_skip);
}
/// Fills a buffer with the positions `[offset..offset+output.len())` integers.
///
/// `offset` is required to have a value >= to the offsets given in previous calls
/// for the given `PositionReaderAbsolute` instance.
pub fn read(&mut self, mut offset: u64, mut output: &mut [u32]) {
offset += self.abs_offset;
assert!(
offset >= self.anchor_offset,
"offset arguments should be increasing."
);
let delta_to_block_offset = offset as i64 - self.block_offset as i64;
if delta_to_block_offset < 0 || delta_to_block_offset >= 128 {
// The first position is not within the first block.
// We need to decompress the first block.
let delta_to_anchor_offset = offset - self.anchor_offset;
let num_blocks_to_skip =
(delta_to_anchor_offset / (COMPRESSION_BLOCK_SIZE as u64)) as usize;
self.advance_num_blocks(num_blocks_to_skip);
self.anchor_offset = offset - (offset % COMPRESSION_BLOCK_SIZE as u64);
self.block_offset = self.anchor_offset;
let num_bits = self.skip_read.get(0);
self.bit_packer
.decompress(self.position_read.as_ref(), self.buffer.as_mut(), num_bits);
} else {
let num_blocks_to_skip =
((self.block_offset - self.anchor_offset) / COMPRESSION_BLOCK_SIZE as u64) as usize;
self.advance_num_blocks(num_blocks_to_skip);
self.anchor_offset = self.block_offset;
}
let mut num_bits = self.skip_read.get(0);
let mut position_data = self.position_read.as_ref();
for i in 1.. {
let offset_in_block = (offset as usize) % COMPRESSION_BLOCK_SIZE;
let remaining_in_block = COMPRESSION_BLOCK_SIZE - offset_in_block;
if remaining_in_block >= output.len() {
output.copy_from_slice(&self.buffer[offset_in_block..][..output.len()]);
break;
}
output[..remaining_in_block].copy_from_slice(&self.buffer[offset_in_block..]);
output = &mut output[remaining_in_block..];
offset += remaining_in_block as u64;
position_data = &position_data[(num_bits as usize * COMPRESSION_BLOCK_SIZE / 8)..];
num_bits = self.skip_read.get(i);
self.bit_packer
.decompress(position_data, self.buffer.as_mut(), num_bits);
self.ahead = Some(0);
self.block_offset += COMPRESSION_BLOCK_SIZE as u64;
}
let block_len = compressed_block_size(num_bits);
self.ahead = Some(read_impl(
self.bit_packer,
&position_data[block_len..],
self.buffer.as_mut(),
self.inner_offset,
&skip_data[1..],
output,
));
}
/// Skip the next `skip_len` integer.
///
/// If a full block is skipped, calling
/// `.skip(...)` will avoid decompressing it.
///
/// May panic if the end of the stream is reached.
pub fn skip(&mut self, skip_len: usize) {
let skip_len_plus_inner_offset = skip_len + self.inner_offset;
let num_blocks_to_advance = skip_len_plus_inner_offset / COMPRESSION_BLOCK_SIZE;
self.inner_offset = skip_len_plus_inner_offset % COMPRESSION_BLOCK_SIZE;
self.ahead = self.ahead.and_then(|num_blocks| {
if num_blocks >= num_blocks_to_advance {
Some(num_blocks - num_blocks_to_advance)
} else {
None
}
});
let skip_len_in_bits = self.skip_read.as_ref()[..num_blocks_to_advance]
.iter()
.map(|num_bits| *num_bits as usize)
.sum::<usize>()
* COMPRESSION_BLOCK_SIZE;
let skip_len_in_bytes = skip_len_in_bits / 8;
self.skip_read.advance(num_blocks_to_advance);
self.position_read.advance(skip_len_in_bytes);
}
}

439
src/postings/block_segment_postings.rs Normal file
View File

@@ -0,0 +1,439 @@
use crate::common::{BinarySerializable, VInt};
use crate::directory::ReadOnlySource;
use crate::postings::compression::{
AlignedBuffer, BlockDecoder, VIntDecoder, COMPRESSION_BLOCK_SIZE,
};
use crate::postings::{BlockInfo, FreqReadingOption, SkipReader};
use crate::schema::IndexRecordOption;
use crate::{DocId, TERMINATED};
/// `BlockSegmentPostings` is a cursor iterating over blocks
/// of documents.
///
/// # Warning
///
/// While it is useful for some very specific high-performance
/// use cases, you should prefer using `SegmentPostings` for most usage.
pub struct BlockSegmentPostings {
pub(crate) doc_decoder: BlockDecoder,
freq_decoder: BlockDecoder,
freq_reading_option: FreqReadingOption,
doc_freq: usize,
data: ReadOnlySource,
skip_reader: SkipReader,
}
fn decode_bitpacked_block(
doc_decoder: &mut BlockDecoder,
freq_decoder_opt: Option<&mut BlockDecoder>,
data: &[u8],
doc_offset: DocId,
doc_num_bits: u8,
tf_num_bits: u8,
) {
let num_consumed_bytes = doc_decoder.uncompress_block_sorted(data, doc_offset, doc_num_bits);
if let Some(freq_decoder) = freq_decoder_opt {
freq_decoder.uncompress_block_unsorted(&data[num_consumed_bytes..], tf_num_bits);
}
}
fn decode_vint_block(
doc_decoder: &mut BlockDecoder,
freq_decoder_opt: Option<&mut BlockDecoder>,
data: &[u8],
doc_offset: DocId,
num_vint_docs: usize,
) {
doc_decoder.clear();
let num_consumed_bytes = doc_decoder.uncompress_vint_sorted(data, doc_offset, num_vint_docs);
if let Some(freq_decoder) = freq_decoder_opt {
freq_decoder.uncompress_vint_unsorted(&data[num_consumed_bytes..], num_vint_docs);
}
}
fn split_into_skips_and_postings(
doc_freq: u32,
data: ReadOnlySource,
) -> (Option<ReadOnlySource>, ReadOnlySource) {
if doc_freq < COMPRESSION_BLOCK_SIZE as u32 {
return (None, data);
}
let mut data_byte_arr = data.as_slice();
let skip_len = VInt::deserialize(&mut data_byte_arr)
.expect("Data corrupted")
.0 as usize;
let vint_len = data.len() - data_byte_arr.len();
let (skip_data, postings_data) = data.slice_from(vint_len).split(skip_len);
(Some(skip_data), postings_data)
}
impl BlockSegmentPostings {
pub(crate) fn from_data(
doc_freq: u32,
data: ReadOnlySource,
record_option: IndexRecordOption,
requested_option: IndexRecordOption,
) -> BlockSegmentPostings {
let freq_reading_option = match (record_option, requested_option) {
(IndexRecordOption::Basic, _) => FreqReadingOption::NoFreq,
(_, IndexRecordOption::Basic) => FreqReadingOption::SkipFreq,
(_, _) => FreqReadingOption::ReadFreq,
};
let (skip_data_opt, postings_data) = split_into_skips_and_postings(doc_freq, data);
let skip_reader = match skip_data_opt {
Some(skip_data) => SkipReader::new(skip_data, doc_freq, record_option),
None => SkipReader::new(ReadOnlySource::empty(), doc_freq, record_option),
};
let doc_freq = doc_freq as usize;
let mut block_segment_postings = BlockSegmentPostings {
doc_decoder: BlockDecoder::with_val(TERMINATED),
freq_decoder: BlockDecoder::with_val(1),
freq_reading_option,
doc_freq,
data: postings_data,
skip_reader,
};
block_segment_postings.advance();
block_segment_postings
}
// Resets the block segment postings on another position
// in the postings file.
//
// This is useful for enumerating through a list of terms,
// and consuming the associated posting lists while avoiding
// reallocating a `BlockSegmentPostings`.
//
// # Warning
//
// This does not reset the positions list.
pub(crate) fn reset(&mut self, doc_freq: u32, postings_data: ReadOnlySource) {
let (skip_data_opt, postings_data) = split_into_skips_and_postings(doc_freq, postings_data);
self.data = ReadOnlySource::new(postings_data);
if let Some(skip_data) = skip_data_opt {
self.skip_reader.reset(skip_data, doc_freq);
} else {
self.skip_reader.reset(ReadOnlySource::empty(), doc_freq);
}
self.doc_freq = doc_freq as usize;
}
/// Returns the document frequency associated to this block postings.
///
/// This `doc_freq` is simply the sum of the length of all of the blocks
/// length, and it does not take in account deleted documents.
pub fn doc_freq(&self) -> usize {
self.doc_freq
}
/// Returns the array of docs in the current block.
///
/// Before the first call to `.advance()`, the block
/// returned by `.docs()` is empty.
#[inline]
pub fn docs(&self) -> &[DocId] {
self.doc_decoder.output_array()
}
pub(crate) fn docs_aligned(&self) -> &AlignedBuffer {
self.doc_decoder.output_aligned()
}
/// Return the document at index `idx` of the block.
#[inline]
pub fn doc(&self, idx: usize) -> u32 {
self.doc_decoder.output(idx)
}
/// Return the array of `term freq` in the block.
#[inline]
pub fn freqs(&self) -> &[u32] {
self.freq_decoder.output_array()
}
/// Return the frequency at index `idx` of the block.
#[inline]
pub fn freq(&self, idx: usize) -> u32 {
self.freq_decoder.output(idx)
}
/// Returns the length of the current block.
///
/// All blocks have a length of `NUM_DOCS_PER_BLOCK`,
/// except the last block that may have a length
/// of any number between 1 and `NUM_DOCS_PER_BLOCK - 1`
#[inline]
pub fn block_len(&self) -> usize {
self.doc_decoder.output_len
}
pub(crate) fn position_offset(&self) -> u64 {
self.skip_reader.position_offset()
}
/// Position on a block that may contains `target_doc`.
///
/// If the current block last element is greater or equal to `target_doc`, return true.
///
/// Returns true if a block that has an element greater or equal to the target is found.
/// Returning true does not guarantee that the smallest element of the block is smaller
/// than the target. It only guarantees that the last element is greater or equal.
///
/// Returns false iff all of the document remaining are smaller than
/// `doc_id`. In that case, all of these document are consumed.
pub fn seek(&mut self, target_doc: DocId) -> bool {
self.skip_reader.seek(target_doc);
self.read_block();
// The last block last doc may actually stop before the target.
self.docs()
.last()
.map(|last_doc| *last_doc >= target_doc)
.unwrap_or(false)
}
fn read_block(&mut self) {
let offset = self.skip_reader.byte_offset();
match self.skip_reader.block_info() {
BlockInfo::BitPacked {
doc_num_bits,
tf_num_bits,
..
} => {
decode_bitpacked_block(
&mut self.doc_decoder,
if let FreqReadingOption::ReadFreq = self.freq_reading_option {
Some(&mut self.freq_decoder)
} else {
None
},
&self.data.as_slice()[offset..],
self.skip_reader.last_doc_in_previous_block,
doc_num_bits,
tf_num_bits,
);
}
BlockInfo::VInt(num_vint_docs) => {
decode_vint_block(
&mut self.doc_decoder,
if let FreqReadingOption::ReadFreq = self.freq_reading_option {
Some(&mut self.freq_decoder)
} else {
None
},
&self.data.as_slice()[offset..],
self.skip_reader.last_doc_in_previous_block,
num_vint_docs as usize,
);
}
}
}
/// Advance to the next block.
///
/// Returns false iff there was no remaining blocks.
pub fn advance(&mut self) -> bool {
if !self.skip_reader.advance() {
return false;
}
self.read_block();
true
}
/// Returns an empty segment postings object
pub fn empty() -> BlockSegmentPostings {
BlockSegmentPostings {
doc_decoder: BlockDecoder::with_val(TERMINATED),
freq_decoder: BlockDecoder::with_val(1),
freq_reading_option: FreqReadingOption::NoFreq,
doc_freq: 0,
data: ReadOnlySource::new(vec![]),
skip_reader: SkipReader::new(ReadOnlySource::new(vec![]), 0, IndexRecordOption::Basic),
}
}
}
#[cfg(test)]
mod tests {
use super::BlockSegmentPostings;
use crate::common::HasLen;
use crate::core::Index;
use crate::docset::{DocSet, TERMINATED};
use crate::postings::postings::Postings;
use crate::postings::SegmentPostings;
use crate::schema::IndexRecordOption;
use crate::schema::Schema;
use crate::schema::Term;
use crate::schema::INDEXED;
use crate::DocId;
#[test]
fn test_empty_segment_postings() {
let mut postings = SegmentPostings::empty();
assert_eq!(postings.advance(), TERMINATED);
assert_eq!(postings.advance(), TERMINATED);
assert_eq!(postings.len(), 0);
}
#[test]
fn test_empty_postings_doc_returns_terminated() {
let mut postings = SegmentPostings::empty();
assert_eq!(postings.doc(), TERMINATED);
assert_eq!(postings.advance(), TERMINATED);
}
#[test]
fn test_empty_postings_doc_term_freq_returns_0() {
let postings = SegmentPostings::empty();
assert_eq!(postings.term_freq(), 1);
}
#[test]
fn test_empty_block_segment_postings() {
let mut postings = BlockSegmentPostings::empty();
assert!(!postings.advance());
assert_eq!(postings.doc_freq(), 0);
}
#[test]
fn test_block_segment_postings() {
let mut block_segments = build_block_postings(&(0..100_000).collect::<Vec<u32>>());
let mut offset: u32 = 0u32;
// checking that the `doc_freq` is correct
assert_eq!(block_segments.doc_freq(), 100_000);
loop {
let block = block_segments.docs();
for (i, doc) in block.iter().cloned().enumerate() {
assert_eq!(offset + (i as u32), doc);
}
offset += block.len() as u32;
if block_segments.advance() {
break;
}
}
}
#[test]
fn test_skip_right_at_new_block() {
let mut doc_ids = (0..128).collect::<Vec<u32>>();
// 128 is missing
doc_ids.push(129);
doc_ids.push(130);
{
let block_segments = build_block_postings(&doc_ids);
let mut docset = SegmentPostings::from_block_postings(block_segments, None);
assert_eq!(docset.seek(128), 129);
assert_eq!(docset.doc(), 129);
assert_eq!(docset.advance(), 130);
assert_eq!(docset.doc(), 130);
assert_eq!(docset.advance(), TERMINATED);
}
{
let block_segments = build_block_postings(&doc_ids);
let mut docset = SegmentPostings::from_block_postings(block_segments, None);
assert_eq!(docset.seek(129), 129);
assert_eq!(docset.doc(), 129);
assert_eq!(docset.advance(), 130);
assert_eq!(docset.doc(), 130);
assert_eq!(docset.advance(), TERMINATED);
}
{
let block_segments = build_block_postings(&doc_ids);
let mut docset = SegmentPostings::from_block_postings(block_segments, None);
assert_eq!(docset.doc(), 0);
assert_eq!(docset.seek(131), TERMINATED);
assert_eq!(docset.doc(), TERMINATED);
}
}
fn build_block_postings(docs: &[DocId]) -> BlockSegmentPostings {
let mut schema_builder = Schema::builder();
let int_field = schema_builder.add_u64_field("id", INDEXED);
let schema = schema_builder.build();
let index = Index::create_in_ram(schema);
let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
let mut last_doc = 0u32;
for &doc in docs {
for _ in last_doc..doc {
index_writer.add_document(doc!(int_field=>1u64));
}
index_writer.add_document(doc!(int_field=>0u64));
last_doc = doc + 1;
}
index_writer.commit().unwrap();
let searcher = index.reader().unwrap().searcher();
let segment_reader = searcher.segment_reader(0);
let inverted_index = segment_reader.inverted_index(int_field);
let term = Term::from_field_u64(int_field, 0u64);
let term_info = inverted_index.get_term_info(&term).unwrap();
inverted_index.read_block_postings_from_terminfo(&term_info, IndexRecordOption::Basic)
}
#[test]
fn test_block_segment_postings_skip() {
for i in 0..4 {
let mut block_postings = build_block_postings(&[3]);
assert_eq!(block_postings.seek(i), true);
assert_eq!(block_postings.seek(i), true);
}
let mut block_postings = build_block_postings(&[3]);
assert_eq!(block_postings.seek(4u32), false);
}
#[test]
fn test_block_segment_postings_skip2() {
let mut docs = vec![0];
for i in 0..1300 {
docs.push((i * i / 100) + i);
}
let mut block_postings = build_block_postings(&docs[..]);
for i in vec![0, 424, 10000] {
assert!(block_postings.seek(i));
let docs = block_postings.docs();
assert!(docs[0] <= i);
assert!(docs.last().cloned().unwrap_or(0u32) >= i);
}
assert!(!block_postings.seek(100_000));
assert!(!block_postings.seek(101_000));
}
#[test]
fn test_reset_block_segment_postings() {
let mut schema_builder = Schema::builder();
let int_field = schema_builder.add_u64_field("id", INDEXED);
let schema = schema_builder.build();
let index = Index::create_in_ram(schema);
let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
// create two postings list, one containg even number,
// the other containing odd numbers.
for i in 0..6 {
let doc = doc!(int_field=> (i % 2) as u64);
index_writer.add_document(doc);
}
index_writer.commit().unwrap();
let searcher = index.reader().unwrap().searcher();
let segment_reader = searcher.segment_reader(0);
let mut block_segments;
{
let term = Term::from_field_u64(int_field, 0u64);
let inverted_index = segment_reader.inverted_index(int_field);
let term_info = inverted_index.get_term_info(&term).unwrap();
block_segments = inverted_index
.read_block_postings_from_terminfo(&term_info, IndexRecordOption::Basic);
}
assert_eq!(block_segments.docs(), &[0, 2, 4]);
{
let term = Term::from_field_u64(int_field, 1u64);
let inverted_index = segment_reader.inverted_index(int_field);
let term_info = inverted_index.get_term_info(&term).unwrap();
inverted_index.reset_block_postings_from_terminfo(&term_info, &mut block_segments);
}
assert!(block_segments.advance());
assert_eq!(block_segments.docs(), &[1, 3, 5]);
}
}

35
src/postings/compression/mod.rs
View File

@@ -18,6 +18,12 @@ pub struct BlockEncoder {
pub output_len: usize,
}
impl Default for BlockEncoder {
fn default() -> Self {
BlockEncoder::new()
}
}
impl BlockEncoder {
pub fn new() -> BlockEncoder {
BlockEncoder {
@@ -55,11 +61,13 @@ pub struct BlockDecoder {
pub output_len: usize,
}
impl BlockDecoder {
pub fn new() -> BlockDecoder {
impl Default for BlockDecoder {
fn default() -> Self {
BlockDecoder::with_val(0u32)
}
}
impl BlockDecoder {
pub fn with_val(val: u32) -> BlockDecoder {
BlockDecoder {
bitpacker: BitPacker4x::new(),
@@ -175,7 +183,7 @@ impl VIntDecoder for BlockDecoder {
vint::uncompress_sorted(compressed_data, &mut self.output.0[..num_els], offset)
}
fn uncompress_vint_unsorted<'a>(&mut self, compressed_data: &'a [u8], num_els: usize) -> usize {
fn uncompress_vint_unsorted(&mut self, compressed_data: &[u8], num_els: usize) -> usize {
self.output_len = num_els;
vint::uncompress_unsorted(compressed_data, &mut self.output.0[..num_els])
}
@@ -191,7 +199,7 @@ pub mod tests {
let vals: Vec<u32> = (0u32..128u32).map(|i| i * 7).collect();
let mut encoder = BlockEncoder::new();
let (num_bits, compressed_data) = encoder.compress_block_sorted(&vals, 0);
let mut decoder = BlockDecoder::new();
let mut decoder = BlockDecoder::default();
{
let consumed_num_bytes = decoder.uncompress_block_sorted(compressed_data, 0, num_bits);
assert_eq!(consumed_num_bytes, compressed_data.len());
@@ -204,9 +212,9 @@ pub mod tests {
#[test]
fn test_encode_sorted_block_with_offset() {
let vals: Vec<u32> = (0u32..128u32).map(|i| 11 + i * 7).collect();
let mut encoder = BlockEncoder::new();
let mut encoder = BlockEncoder::default();
let (num_bits, compressed_data) = encoder.compress_block_sorted(&vals, 10);
let mut decoder = BlockDecoder::new();
let mut decoder = BlockDecoder::default();
{
let consumed_num_bytes = decoder.uncompress_block_sorted(compressed_data, 10, num_bits);
assert_eq!(consumed_num_bytes, compressed_data.len());
@@ -221,11 +229,11 @@ pub mod tests {
let mut compressed: Vec<u8> = Vec::new();
let n = 128;
let vals: Vec<u32> = (0..n).map(|i| 11u32 + (i as u32) * 7u32).collect();
let mut encoder = BlockEncoder::new();
let mut encoder = BlockEncoder::default();
let (num_bits, compressed_data) = encoder.compress_block_sorted(&vals, 10);
compressed.extend_from_slice(compressed_data);
compressed.push(173u8);
let mut decoder = BlockDecoder::new();
let mut decoder = BlockDecoder::default();
{
let consumed_num_bytes = decoder.uncompress_block_sorted(&compressed, 10, num_bits);
assert_eq!(consumed_num_bytes, compressed.len() - 1);
@@ -241,11 +249,11 @@ pub mod tests {
let mut compressed: Vec<u8> = Vec::new();
let n = 128;
let vals: Vec<u32> = (0..n).map(|i| 11u32 + (i as u32) * 7u32 % 12).collect();
let mut encoder = BlockEncoder::new();
let mut encoder = BlockEncoder::default();
let (num_bits, compressed_data) = encoder.compress_block_unsorted(&vals);
compressed.extend_from_slice(compressed_data);
compressed.push(173u8);
let mut decoder = BlockDecoder::new();
let mut decoder = BlockDecoder::default();
{
let consumed_num_bytes = decoder.uncompress_block_unsorted(&compressed, num_bits);
assert_eq!(consumed_num_bytes + 1, compressed.len());
@@ -256,6 +264,11 @@ pub mod tests {
}
}
#[test]
fn test_block_decoder_initialization() {
let block = BlockDecoder::with_val(TERMINATED);
assert_eq!(block.output(0), TERMINATED);
}
#[test]
fn test_encode_vint() {
{
@@ -265,7 +278,7 @@ pub mod tests {
for offset in &[0u32, 1u32, 2u32] {
let encoded_data = encoder.compress_vint_sorted(&input, *offset);
assert!(encoded_data.len() <= expected_length);
let mut decoder = BlockDecoder::new();
let mut decoder = BlockDecoder::default();
let consumed_num_bytes =
decoder.uncompress_vint_sorted(&encoded_data, *offset, input.len());
assert_eq!(consumed_num_bytes, encoded_data.len());

12
src/postings/mod.rs
View File

@@ -3,11 +3,8 @@ Postings module (also called inverted index)
*/
mod block_search;
mod block_segment_postings;
pub(crate) mod compression;
/// Postings module
///
/// Postings, also called inverted lists, is the key datastructure
/// to full-text search.
mod postings;
mod postings_writer;
mod recorder;
@@ -22,18 +19,17 @@ pub(crate) use self::block_search::BlockSearcher;
pub(crate) use self::postings_writer::MultiFieldPostingsWriter;
pub use self::serializer::{FieldSerializer, InvertedIndexSerializer};
use self::compression::COMPRESSION_BLOCK_SIZE;
pub use self::postings::Postings;
pub(crate) use self::skip::SkipReader;
pub(crate) use self::skip::{BlockInfo, SkipReader};
pub use self::term_info::TermInfo;
pub use self::segment_postings::{BlockSegmentPostings, SegmentPostings};
pub use self::block_segment_postings::BlockSegmentPostings;
pub use self::segment_postings::SegmentPostings;
pub(crate) use self::stacker::compute_table_size;
pub use crate::common::HasLen;
pub(crate) const USE_SKIP_INFO_LIMIT: u32 = COMPRESSION_BLOCK_SIZE as u32;
pub(crate) type UnorderedTermId = u64;
#[cfg_attr(feature = "cargo-clippy", allow(clippy::enum_variant_names))]

629
src/postings/segment_postings.rs
View File

@@ -1,54 +1,19 @@
use crate::common::HasLen;
use crate::common::{BinarySerializable, VInt};
use crate::docset::{DocSet, TERMINATED};
use crate::positions::PositionReader;
use crate::postings::compression::{compressed_block_size, AlignedBuffer};
use crate::postings::compression::{BlockDecoder, VIntDecoder, COMPRESSION_BLOCK_SIZE};
use crate::postings::compression::COMPRESSION_BLOCK_SIZE;
use crate::postings::serializer::PostingsSerializer;
use crate::postings::BlockSearcher;
use crate::postings::FreqReadingOption;
use crate::postings::Postings;
use crate::postings::SkipReader;
use crate::postings::USE_SKIP_INFO_LIMIT;
use crate::schema::IndexRecordOption;
use crate::DocId;
use owned_read::OwnedRead;
use tantivy_fst::Streamer;
struct PositionComputer {
// store the amount of position int
// before reading positions.
//
// if none, position are already loaded in
// the positions vec.
position_to_skip: usize,
position_reader: PositionReader,
}
impl PositionComputer {
pub fn new(position_reader: PositionReader) -> PositionComputer {
PositionComputer {
position_to_skip: 0,
position_reader,
}
}
pub fn add_skip(&mut self, num_skip: usize) {
self.position_to_skip += num_skip;
}
// Positions can only be read once.
pub fn positions_with_offset(&mut self, offset: u32, output: &mut [u32]) {
self.position_reader.skip(self.position_to_skip);
self.position_to_skip = 0;
self.position_reader.read(output);
let mut cum = offset;
for output_mut in output.iter_mut() {
cum += *output_mut;
*output_mut = cum;
}
}
}
use crate::directory::ReadOnlySource;
use crate::postings::BlockSegmentPostings;
/// `SegmentPostings` represents the inverted list or postings associated to
/// a term in a `Segment`.
@@ -58,22 +23,19 @@ impl PositionComputer {
pub struct SegmentPostings {
block_cursor: BlockSegmentPostings,
cur: usize,
position_computer: Option<PositionComputer>,
position_reader: Option<PositionReader>,
block_searcher: BlockSearcher,
}
impl SegmentPostings {
/// Returns an empty segment postings object
pub fn empty() -> Self {
let empty_block_cursor = BlockSegmentPostings::empty();
let mut segment_postings = SegmentPostings {
block_cursor: empty_block_cursor,
cur: COMPRESSION_BLOCK_SIZE,
position_computer: None,
SegmentPostings {
block_cursor: BlockSegmentPostings::empty(),
cur: 0,
position_reader: None,
block_searcher: BlockSearcher::default(),
};
segment_postings.advance();
segment_postings
}
}
/// Creates a segment postings object with the given documents
@@ -97,15 +59,13 @@ impl SegmentPostings {
}
let block_segment_postings = BlockSegmentPostings::from_data(
docs.len() as u32,
OwnedRead::new(buffer),
ReadOnlySource::from(buffer),
IndexRecordOption::Basic,
IndexRecordOption::Basic,
);
SegmentPostings::from_block_postings(block_segment_postings, None)
}
}
impl SegmentPostings {
/// Reads a Segment postings from an &[u8]
///
/// * `len` - number of document in the posting lists.
@@ -114,16 +74,14 @@ impl SegmentPostings {
/// frequencies and/or positions
pub(crate) fn from_block_postings(
segment_block_postings: BlockSegmentPostings,
positions_stream_opt: Option<PositionReader>,
position_reader: Option<PositionReader>,
) -> SegmentPostings {
let mut postings = SegmentPostings {
SegmentPostings {
block_cursor: segment_block_postings,
cur: COMPRESSION_BLOCK_SIZE, // cursor within the block
position_computer: positions_stream_opt.map(PositionComputer::new),
cur: 0, // cursor within the block
position_reader,
block_searcher: BlockSearcher::default(),
};
postings.advance();
postings
}
}
}
@@ -132,12 +90,6 @@ impl DocSet for SegmentPostings {
// next needs to be called a first time to point to the correct element.
#[inline]
fn advance(&mut self) -> DocId {
if self.position_computer.is_some() && self.cur < COMPRESSION_BLOCK_SIZE {
let term_freq = self.term_freq() as usize;
if let Some(position_computer) = self.position_computer.as_mut() {
position_computer.add_skip(term_freq);
}
}
self.cur += 1;
if self.cur >= self.block_cursor.block_len() {
if self.block_cursor.advance() {
@@ -151,17 +103,13 @@ impl DocSet for SegmentPostings {
}
fn seek(&mut self, target: DocId) -> DocId {
if self.doc() >= target {
return self.doc();
let doc = self.doc();
if doc >= target {
return doc;
}
// In the following, thanks to the call to advance above,
// we know that the position is not loaded and we need
// to skip every doc_freq we cross.
// skip blocks until one that might contain the target
// check if we need to go to the next block
let mut sum_freqs_skipped: u32 = 0;
if self
.block_cursor
.docs()
@@ -170,23 +118,7 @@ impl DocSet for SegmentPostings {
.unwrap_or(true)
{
// We are not in the right block.
if self.position_computer.is_some() {
// First compute all of the freqs skipped from the current block.
sum_freqs_skipped = self.block_cursor.freqs()[self.cur..].iter().sum::<u32>();
match self.block_cursor.skip_to(target) {
BlockSegmentPostingsSkipResult::Success(block_skip_freqs) => {
sum_freqs_skipped += block_skip_freqs;
}
BlockSegmentPostingsSkipResult::Terminated => {
self.block_cursor.doc_decoder.clear();
self.cur = 0;
return TERMINATED;
}
}
} else if self.block_cursor.skip_to(target)
== BlockSegmentPostingsSkipResult::Terminated
{
// no positions needed. no need to sum freqs.
if !self.block_cursor.seek(target) {
self.block_cursor.doc_decoder.clear();
self.cur = 0;
return TERMINATED;
@@ -200,10 +132,6 @@ impl DocSet for SegmentPostings {
let output = self.block_cursor.docs_aligned();
let new_cur = self.block_searcher.search_in_block(&output, cur, target);
if let Some(position_computer) = self.position_computer.as_mut() {
sum_freqs_skipped += self.block_cursor.freqs()[cur..new_cur].iter().sum::<u32>();
position_computer.add_skip(sum_freqs_skipped as usize);
}
self.cur = new_cur;
// `doc` is now the first element >= `target`
@@ -225,23 +153,6 @@ impl DocSet for SegmentPostings {
fn size_hint(&self) -> u32 {
self.len() as u32
}
/*
fn append_to_bitset(&mut self, bitset: &mut BitSet) {
// finish the current block
if self.advance() {
for &doc in &self.block_cursor.docs()[self.cur..] {
bitset.insert(doc);
}
// ... iterate through the remaining blocks.
while self.block_cursor.advance() {
for &doc in self.block_cursor.docs() {
bitset.insert(doc);
}
}
}
}
*/
}
impl HasLen for SegmentPostings {
@@ -275,338 +186,33 @@ impl Postings for SegmentPostings {
fn positions_with_offset(&mut self, offset: u32, output: &mut Vec<u32>) {
let term_freq = self.term_freq() as usize;
if let Some(position_comp) = self.position_computer.as_mut() {
if let Some(position_reader) = self.position_reader.as_mut() {
let read_offset = self.block_cursor.position_offset()
+ (self.block_cursor.freqs()[..self.cur]
.iter()
.cloned()
.sum::<u32>() as u64);
output.resize(term_freq, 0u32);
position_comp.positions_with_offset(offset, &mut output[..]);
position_reader.read(read_offset, &mut output[..]);
let mut cum = offset;
for output_mut in output.iter_mut() {
cum += *output_mut;
*output_mut = cum;
}
} else {
output.clear();
}
}
}
/// `BlockSegmentPostings` is a cursor iterating over blocks
/// of documents.
///
/// # Warning
///
/// While it is useful for some very specific high-performance
/// use cases, you should prefer using `SegmentPostings` for most usage.
pub struct BlockSegmentPostings {
doc_decoder: BlockDecoder,
freq_decoder: BlockDecoder,
freq_reading_option: FreqReadingOption,
doc_freq: usize,
doc_offset: DocId,
num_vint_docs: usize,
remaining_data: OwnedRead,
skip_reader: SkipReader,
}
fn split_into_skips_and_postings(
doc_freq: u32,
mut data: OwnedRead,
) -> (Option<OwnedRead>, OwnedRead) {
if doc_freq < USE_SKIP_INFO_LIMIT {
return (None, data);
}
let skip_len = VInt::deserialize(&mut data).expect("Data corrupted").0 as usize;
let mut postings_data = data.clone();
postings_data.advance(skip_len);
data.clip(skip_len);
(Some(data), postings_data)
}
#[derive(Debug, Eq, PartialEq)]
pub enum BlockSegmentPostingsSkipResult {
Terminated,
Success(u32), //< number of term freqs to skip
}
impl BlockSegmentPostings {
pub(crate) fn from_data(
doc_freq: u32,
data: OwnedRead,
record_option: IndexRecordOption,
requested_option: IndexRecordOption,
) -> BlockSegmentPostings {
let freq_reading_option = match (record_option, requested_option) {
(IndexRecordOption::Basic, _) => FreqReadingOption::NoFreq,
(_, IndexRecordOption::Basic) => FreqReadingOption::SkipFreq,
(_, _) => FreqReadingOption::ReadFreq,
};
let (skip_data_opt, postings_data) = split_into_skips_and_postings(doc_freq, data);
let skip_reader = match skip_data_opt {
Some(skip_data) => SkipReader::new(skip_data, record_option),
None => SkipReader::new(OwnedRead::new(&[][..]), record_option),
};
let doc_freq = doc_freq as usize;
let num_vint_docs = doc_freq % COMPRESSION_BLOCK_SIZE;
BlockSegmentPostings {
num_vint_docs,
doc_decoder: BlockDecoder::new(),
freq_decoder: BlockDecoder::with_val(1),
freq_reading_option,
doc_offset: 0,
doc_freq,
remaining_data: postings_data,
skip_reader,
}
}
// Resets the block segment postings on another position
// in the postings file.
//
// This is useful for enumerating through a list of terms,
// and consuming the associated posting lists while avoiding
// reallocating a `BlockSegmentPostings`.
//
// # Warning
//
// This does not reset the positions list.
pub(crate) fn reset(&mut self, doc_freq: u32, postings_data: OwnedRead) {
let (skip_data_opt, postings_data) = split_into_skips_and_postings(doc_freq, postings_data);
let num_vint_docs = (doc_freq as usize) & (COMPRESSION_BLOCK_SIZE - 1);
self.num_vint_docs = num_vint_docs;
self.remaining_data = postings_data;
if let Some(skip_data) = skip_data_opt {
self.skip_reader.reset(skip_data);
} else {
self.skip_reader.reset(OwnedRead::new(&[][..]))
}
self.doc_offset = 0;
self.doc_freq = doc_freq as usize;
}
/// Returns the document frequency associated to this block postings.
///
/// This `doc_freq` is simply the sum of the length of all of the blocks
/// length, and it does not take in account deleted documents.
pub fn doc_freq(&self) -> usize {
self.doc_freq
}
/// Returns the array of docs in the current block.
///
/// Before the first call to `.advance()`, the block
/// returned by `.docs()` is empty.
#[inline]
pub fn docs(&self) -> &[DocId] {
self.doc_decoder.output_array()
}
pub(crate) fn docs_aligned(&self) -> &AlignedBuffer {
self.doc_decoder.output_aligned()
}
/// Return the document at index `idx` of the block.
#[inline]
pub fn doc(&self, idx: usize) -> u32 {
self.doc_decoder.output(idx)
}
/// Return the array of `term freq` in the block.
#[inline]
pub fn freqs(&self) -> &[u32] {
self.freq_decoder.output_array()
}
/// Return the frequency at index `idx` of the block.
#[inline]
pub fn freq(&self, idx: usize) -> u32 {
self.freq_decoder.output(idx)
}
/// Returns the length of the current block.
///
/// All blocks have a length of `NUM_DOCS_PER_BLOCK`,
/// except the last block that may have a length
/// of any number between 1 and `NUM_DOCS_PER_BLOCK - 1`
#[inline]
fn block_len(&self) -> usize {
self.doc_decoder.output_len
}
/// position on a block that may contains `doc_id`.
/// Always advance the current block.
///
/// Returns true if a block that has an element greater or equal to the target is found.
/// Returning true does not guarantee that the smallest element of the block is smaller
/// than the target. It only guarantees that the last element is greater or equal.
///
/// Returns false iff all of the document remaining are smaller than
/// `doc_id`. In that case, all of these document are consumed.
///
pub fn skip_to(&mut self, target_doc: DocId) -> BlockSegmentPostingsSkipResult {
let mut skip_freqs = 0u32;
while self.skip_reader.advance() {
if self.skip_reader.doc() >= target_doc {
// the last document of the current block is larger
// than the target.
//
// We found our block!
let num_bits = self.skip_reader.doc_num_bits();
let num_consumed_bytes = self.doc_decoder.uncompress_block_sorted(
self.remaining_data.as_ref(),
self.doc_offset,
num_bits,
);
self.remaining_data.advance(num_consumed_bytes);
let tf_num_bits = self.skip_reader.tf_num_bits();
match self.freq_reading_option {
FreqReadingOption::NoFreq => {}
FreqReadingOption::SkipFreq => {
let num_bytes_to_skip = compressed_block_size(tf_num_bits);
self.remaining_data.advance(num_bytes_to_skip);
}
FreqReadingOption::ReadFreq => {
let num_consumed_bytes = self
.freq_decoder
.uncompress_block_unsorted(self.remaining_data.as_ref(), tf_num_bits);
self.remaining_data.advance(num_consumed_bytes);
}
}
self.doc_offset = self.skip_reader.doc();
return BlockSegmentPostingsSkipResult::Success(skip_freqs);
} else {
skip_freqs += self.skip_reader.tf_sum();
let advance_len = self.skip_reader.total_block_len();
self.doc_offset = self.skip_reader.doc();
self.remaining_data.advance(advance_len);
}
}
self.doc_decoder.clear();
if self.num_vint_docs == 0 {
return BlockSegmentPostingsSkipResult::Terminated;
}
// we are now on the last, incomplete, variable encoded block.
let num_compressed_bytes = self.doc_decoder.uncompress_vint_sorted(
self.remaining_data.as_ref(),
self.doc_offset,
self.num_vint_docs,
);
self.remaining_data.advance(num_compressed_bytes);
match self.freq_reading_option {
FreqReadingOption::NoFreq | FreqReadingOption::SkipFreq => {}
FreqReadingOption::ReadFreq => {
self.freq_decoder
.uncompress_vint_unsorted(self.remaining_data.as_ref(), self.num_vint_docs);
}
}
self.num_vint_docs = 0;
self.docs()
.last()
.map(|last_doc| {
if *last_doc >= target_doc {
BlockSegmentPostingsSkipResult::Success(skip_freqs)
} else {
BlockSegmentPostingsSkipResult::Terminated
}
})
.unwrap_or(BlockSegmentPostingsSkipResult::Terminated)
}
/// Advance to the next block.
///
/// Returns false iff there was no remaining blocks.
pub fn advance(&mut self) -> bool {
if self.skip_reader.advance() {
let num_bits = self.skip_reader.doc_num_bits();
let num_consumed_bytes = self.doc_decoder.uncompress_block_sorted(
self.remaining_data.as_ref(),
self.doc_offset,
num_bits,
);
self.remaining_data.advance(num_consumed_bytes);
let tf_num_bits = self.skip_reader.tf_num_bits();
match self.freq_reading_option {
FreqReadingOption::NoFreq => {}
FreqReadingOption::SkipFreq => {
let num_bytes_to_skip = compressed_block_size(tf_num_bits);
self.remaining_data.advance(num_bytes_to_skip);
}
FreqReadingOption::ReadFreq => {
let num_consumed_bytes = self
.freq_decoder
.uncompress_block_unsorted(self.remaining_data.as_ref(), tf_num_bits);
self.remaining_data.advance(num_consumed_bytes);
}
}
// it will be used as the next offset.
self.doc_offset = self.doc_decoder.output(COMPRESSION_BLOCK_SIZE - 1);
return true;
}
self.doc_decoder.clear();
if self.num_vint_docs == 0 {
return false;
}
let num_compressed_bytes = self.doc_decoder.uncompress_vint_sorted(
self.remaining_data.as_ref(),
self.doc_offset,
self.num_vint_docs,
);
self.remaining_data.advance(num_compressed_bytes);
match self.freq_reading_option {
FreqReadingOption::NoFreq | FreqReadingOption::SkipFreq => {}
FreqReadingOption::ReadFreq => {
self.freq_decoder
.uncompress_vint_unsorted(self.remaining_data.as_ref(), self.num_vint_docs);
}
}
self.num_vint_docs = 0;
true
}
/// Returns an empty segment postings object
pub fn empty() -> BlockSegmentPostings {
BlockSegmentPostings {
num_vint_docs: 0,
doc_decoder: BlockDecoder::new(),
freq_decoder: BlockDecoder::with_val(1),
freq_reading_option: FreqReadingOption::NoFreq,
doc_offset: 0,
doc_freq: 0,
remaining_data: OwnedRead::new(vec![]),
skip_reader: SkipReader::new(OwnedRead::new(vec![]), IndexRecordOption::Basic),
}
}
}
impl<'b> Streamer<'b> for BlockSegmentPostings {
type Item = &'b [DocId];
fn next(&'b mut self) -> Option<&'b [DocId]> {
if self.advance() {
Some(self.docs())
} else {
None
}
}
}
#[cfg(test)]
mod tests {
use super::BlockSegmentPostings;
use super::BlockSegmentPostingsSkipResult;
use super::SegmentPostings;
use crate::common::HasLen;
use crate::core::Index;
use crate::docset::{DocSet, TERMINATED};
use crate::postings::postings::Postings;
use crate::schema::IndexRecordOption;
use crate::schema::Schema;
use crate::schema::Term;
use crate::schema::INDEXED;
use crate::DocId;
use tantivy_fst::Streamer;
#[test]
fn test_empty_segment_postings() {
@@ -628,165 +234,4 @@ mod tests {
let postings = SegmentPostings::empty();
assert_eq!(postings.term_freq(), 1);
}
#[test]
fn test_empty_block_segment_postings() {
let mut postings = BlockSegmentPostings::empty();
assert!(!postings.advance());
assert_eq!(postings.doc_freq(), 0);
}
#[test]
fn test_block_segment_postings() {
let mut block_segments = build_block_postings(&(0..100_000).collect::<Vec<u32>>());
let mut offset: u32 = 0u32;
// checking that the block before calling advance is empty
assert!(block_segments.docs().is_empty());
// checking that the `doc_freq` is correct
assert_eq!(block_segments.doc_freq(), 100_000);
while let Some(block) = block_segments.next() {
for (i, doc) in block.iter().cloned().enumerate() {
assert_eq!(offset + (i as u32), doc);
}
offset += block.len() as u32;
}
}
#[test]
fn test_skip_right_at_new_block() {
let mut doc_ids = (0..128).collect::<Vec<u32>>();
doc_ids.push(129);
doc_ids.push(130);
{
let block_segments = build_block_postings(&doc_ids);
let mut docset = SegmentPostings::from_block_postings(block_segments, None);
assert_eq!(docset.seek(128), 129);
assert_eq!(docset.doc(), 129);
assert_eq!(docset.advance(), 130);
assert_eq!(docset.doc(), 130);
assert_eq!(docset.advance(), TERMINATED);
}
{
let block_segments = build_block_postings(&doc_ids);
let mut docset = SegmentPostings::from_block_postings(block_segments, None);
assert_eq!(docset.seek(129), 129);
assert_eq!(docset.doc(), 129);
assert_eq!(docset.advance(), 130);
assert_eq!(docset.doc(), 130);
assert_eq!(docset.advance(), TERMINATED);
}
{
let block_segments = build_block_postings(&doc_ids);
let mut docset = SegmentPostings::from_block_postings(block_segments, None);
assert_eq!(docset.doc(), 0);
assert_eq!(docset.seek(131), TERMINATED);
assert_eq!(docset.doc(), TERMINATED);
}
}
fn build_block_postings(docs: &[DocId]) -> BlockSegmentPostings {
let mut schema_builder = Schema::builder();
let int_field = schema_builder.add_u64_field("id", INDEXED);
let schema = schema_builder.build();
let index = Index::create_in_ram(schema);
let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
let mut last_doc = 0u32;
for &doc in docs {
for _ in last_doc..doc {
index_writer.add_document(doc!(int_field=>1u64));
}
index_writer.add_document(doc!(int_field=>0u64));
last_doc = doc + 1;
}
index_writer.commit().unwrap();
let searcher = index.reader().unwrap().searcher();
let segment_reader = searcher.segment_reader(0);
let inverted_index = segment_reader.inverted_index(int_field);
let term = Term::from_field_u64(int_field, 0u64);
let term_info = inverted_index.get_term_info(&term).unwrap();
inverted_index.read_block_postings_from_terminfo(&term_info, IndexRecordOption::Basic)
}
#[test]
fn test_block_segment_postings_skip() {
for i in 0..4 {
let mut block_postings = build_block_postings(&[3]);
assert_eq!(
block_postings.skip_to(i),
BlockSegmentPostingsSkipResult::Success(0u32)
);
assert_eq!(
block_postings.skip_to(i),
BlockSegmentPostingsSkipResult::Terminated
);
}
let mut block_postings = build_block_postings(&[3]);
assert_eq!(
block_postings.skip_to(4u32),
BlockSegmentPostingsSkipResult::Terminated
);
}
#[test]
fn test_block_segment_postings_skip2() {
let mut docs = vec![0];
for i in 0..1300 {
docs.push((i * i / 100) + i);
}
let mut block_postings = build_block_postings(&docs[..]);
for i in vec![0, 424, 10000] {
assert_eq!(
block_postings.skip_to(i),
BlockSegmentPostingsSkipResult::Success(0u32)
);
let docs = block_postings.docs();
assert!(docs[0] <= i);
assert!(docs.last().cloned().unwrap_or(0u32) >= i);
}
assert_eq!(
block_postings.skip_to(100_000),
BlockSegmentPostingsSkipResult::Terminated
);
assert_eq!(
block_postings.skip_to(101_000),
BlockSegmentPostingsSkipResult::Terminated
);
}
#[test]
fn test_reset_block_segment_postings() {
let mut schema_builder = Schema::builder();
let int_field = schema_builder.add_u64_field("id", INDEXED);
let schema = schema_builder.build();
let index = Index::create_in_ram(schema);
let mut index_writer = index.writer_with_num_threads(1, 3_000_000).unwrap();
// create two postings list, one containg even number,
// the other containing odd numbers.
for i in 0..6 {
let doc = doc!(int_field=> (i % 2) as u64);
index_writer.add_document(doc);
}
index_writer.commit().unwrap();
let searcher = index.reader().unwrap().searcher();
let segment_reader = searcher.segment_reader(0);
let mut block_segments;
{
let term = Term::from_field_u64(int_field, 0u64);
let inverted_index = segment_reader.inverted_index(int_field);
let term_info = inverted_index.get_term_info(&term).unwrap();
block_segments = inverted_index
.read_block_postings_from_terminfo(&term_info, IndexRecordOption::Basic);
}
assert!(block_segments.advance());
assert_eq!(block_segments.docs(), &[0, 2, 4]);
{
let term = Term::from_field_u64(int_field, 1u64);
let inverted_index = segment_reader.inverted_index(int_field);
let term_info = inverted_index.get_term_info(&term).unwrap();
inverted_index.reset_block_postings_from_terminfo(&term_info, &mut block_segments);
}
assert!(block_segments.advance());
assert_eq!(block_segments.docs(), &[1, 3, 5]);
}
}

3
src/postings/serializer.rs
View File

@@ -6,7 +6,6 @@ use crate::directory::WritePtr;
use crate::positions::PositionSerializer;
use crate::postings::compression::{BlockEncoder, VIntEncoder, COMPRESSION_BLOCK_SIZE};
use crate::postings::skip::SkipSerializer;
use crate::postings::USE_SKIP_INFO_LIMIT;
use crate::schema::Schema;
use crate::schema::{Field, FieldEntry, FieldType};
use crate::termdict::{TermDictionaryBuilder, TermOrdinal};
@@ -391,7 +390,7 @@ impl<W: Write> PostingsSerializer<W> {
}
self.block.clear();
}
if doc_freq >= USE_SKIP_INFO_LIMIT {
if doc_freq >= COMPRESSION_BLOCK_SIZE as u32 {
let skip_data = self.skip_write.data();
VInt(skip_data.len() as u64).serialize(&mut self.output_write)?;
self.output_write.write_all(skip_data)?;

256
src/postings/skip.rs
View File

@@ -1,7 +1,8 @@
use crate::common::BinarySerializable;
use crate::postings::compression::COMPRESSION_BLOCK_SIZE;
use crate::directory::ReadOnlySource;
use crate::postings::compression::{compressed_block_size, COMPRESSION_BLOCK_SIZE};
use crate::schema::IndexRecordOption;
use crate::DocId;
use crate::{DocId, TERMINATED};
use owned_read::OwnedRead;
pub struct SkipSerializer {
@@ -50,80 +51,143 @@ impl SkipSerializer {
}
pub(crate) struct SkipReader {
doc: DocId,
last_doc_in_block: DocId,
pub(crate) last_doc_in_previous_block: DocId,
owned_read: OwnedRead,
doc_num_bits: u8,
tf_num_bits: u8,
tf_sum: u32,
skip_info: IndexRecordOption,
byte_offset: usize,
remaining_docs: u32, // number of docs remaining, including the
// documents in the current block.
block_info: BlockInfo,
position_offset: u64,
}
#[derive(Clone, Eq, PartialEq, Copy, Debug)]
pub(crate) enum BlockInfo {
BitPacked {
doc_num_bits: u8,
tf_num_bits: u8,
tf_sum: u32,
},
VInt(u32),
}
impl Default for BlockInfo {
fn default() -> Self {
BlockInfo::VInt(0)
}
}
impl SkipReader {
pub fn new(data: OwnedRead, skip_info: IndexRecordOption) -> SkipReader {
pub fn new(data: ReadOnlySource, doc_freq: u32, skip_info: IndexRecordOption) -> SkipReader {
SkipReader {
doc: 0u32,
owned_read: data,
last_doc_in_block: 0u32,
last_doc_in_previous_block: 0u32,
owned_read: OwnedRead::new(data),
skip_info,
doc_num_bits: 0u8,
tf_num_bits: 0u8,
tf_sum: 0u32,
block_info: BlockInfo::default(),
byte_offset: 0,
remaining_docs: doc_freq,
position_offset: 0u64,
}
}
pub fn reset(&mut self, data: OwnedRead) {
self.doc = 0u32;
self.owned_read = data;
self.doc_num_bits = 0u8;
self.tf_num_bits = 0u8;
self.tf_sum = 0u32;
}
pub fn total_block_len(&self) -> usize {
(self.doc_num_bits + self.tf_num_bits) as usize * COMPRESSION_BLOCK_SIZE / 8
pub fn reset(&mut self, data: ReadOnlySource, doc_freq: u32) {
self.last_doc_in_block = 0u32;
self.last_doc_in_previous_block = 0u32;
self.owned_read = OwnedRead::new(data);
self.block_info = BlockInfo::default();
self.byte_offset = 0;
self.remaining_docs = doc_freq;
}
pub fn doc(&self) -> DocId {
self.doc
self.last_doc_in_block
}
pub fn doc_num_bits(&self) -> u8 {
self.doc_num_bits
pub fn position_offset(&self) -> u64 {
self.position_offset
}
/// Number of bits used to encode term frequencies
pub fn byte_offset(&self) -> usize {
self.byte_offset
}
fn read_block_info(&mut self) {
let doc_delta = u32::deserialize(&mut self.owned_read).expect("Skip data corrupted");
self.last_doc_in_block += doc_delta as DocId;
let doc_num_bits = self.owned_read.get(0);
match self.skip_info {
IndexRecordOption::Basic => {
self.owned_read.advance(1);
self.block_info = BlockInfo::BitPacked {
doc_num_bits,
tf_num_bits: 0,
tf_sum: 0,
};
}
IndexRecordOption::WithFreqs => {
let tf_num_bits = self.owned_read.get(1);
self.block_info = BlockInfo::BitPacked {
doc_num_bits,
tf_num_bits,
tf_sum: 0,
};
self.owned_read.advance(2);
}
IndexRecordOption::WithFreqsAndPositions => {
let tf_num_bits = self.owned_read.get(1);
self.owned_read.advance(2);
let tf_sum = u32::deserialize(&mut self.owned_read).expect("Failed reading tf_sum");
self.block_info = BlockInfo::BitPacked {
doc_num_bits,
tf_num_bits,
tf_sum,
};
}
}
}
pub fn block_info(&self) -> BlockInfo {
self.block_info
}
/// Advance the skip reader to the block that may contain the target.
///
/// 0 if term frequencies are not enabled.
pub fn tf_num_bits(&self) -> u8 {
self.tf_num_bits
}
pub fn tf_sum(&self) -> u32 {
self.tf_sum
/// If the target is larger than all documents, the skip_reader
/// then advance to the last Variable In block.
///
/// Returns true if the last block is reached.
pub fn seek(&mut self, target: DocId) {
while self.doc() < target {
self.advance();
}
}
pub fn advance(&mut self) -> bool {
if self.owned_read.as_ref().is_empty() {
false
} else {
let doc_delta = u32::deserialize(&mut self.owned_read).expect("Skip data corrupted");
self.doc += doc_delta as DocId;
self.doc_num_bits = self.owned_read.get(0);
match self.skip_info {
IndexRecordOption::Basic => {
self.owned_read.advance(1);
}
IndexRecordOption::WithFreqs => {
self.tf_num_bits = self.owned_read.get(1);
self.owned_read.advance(2);
}
IndexRecordOption::WithFreqsAndPositions => {
self.tf_num_bits = self.owned_read.get(1);
self.owned_read.advance(2);
self.tf_sum =
u32::deserialize(&mut self.owned_read).expect("Failed reading tf_sum");
}
match self.block_info {
BlockInfo::BitPacked {
doc_num_bits,
tf_num_bits,
tf_sum,
} => {
self.remaining_docs -= COMPRESSION_BLOCK_SIZE as u32;
self.byte_offset += compressed_block_size(doc_num_bits + tf_num_bits);
self.position_offset += tf_sum as u64;
}
BlockInfo::VInt(num_vint_docs) => {
self.remaining_docs -= num_vint_docs;
}
}
self.last_doc_in_previous_block = self.last_doc_in_block;
if self.remaining_docs >= COMPRESSION_BLOCK_SIZE as u32 {
self.read_block_info();
true
} else {
self.last_doc_in_block = TERMINATED;
self.block_info = BlockInfo::VInt(self.remaining_docs);
self.remaining_docs > 0
}
}
}
@@ -131,9 +195,11 @@ impl SkipReader {
#[cfg(test)]
mod tests {
use super::BlockInfo;
use super::IndexRecordOption;
use super::{SkipReader, SkipSerializer};
use owned_read::OwnedRead;
use crate::directory::ReadOnlySource;
use crate::postings::compression::COMPRESSION_BLOCK_SIZE;
#[test]
fn test_skip_with_freq() {
@@ -145,15 +211,34 @@ mod tests {
skip_serializer.write_term_freq(2u8);
skip_serializer.data().to_owned()
};
let mut skip_reader = SkipReader::new(OwnedRead::new(buf), IndexRecordOption::WithFreqs);
let doc_freq = 3u32 + (COMPRESSION_BLOCK_SIZE * 2) as u32;
let mut skip_reader = SkipReader::new(
ReadOnlySource::new(buf),
doc_freq,
IndexRecordOption::WithFreqs,
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.doc(), 1u32);
assert_eq!(skip_reader.doc_num_bits(), 2u8);
assert_eq!(skip_reader.tf_num_bits(), 3u8);
assert_eq!(
skip_reader.block_info(),
BlockInfo::BitPacked {
doc_num_bits: 2u8,
tf_num_bits: 3u8,
tf_sum: 0
}
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.doc(), 5u32);
assert_eq!(skip_reader.doc_num_bits(), 5u8);
assert_eq!(skip_reader.tf_num_bits(), 2u8);
assert_eq!(
skip_reader.block_info(),
BlockInfo::BitPacked {
doc_num_bits: 5u8,
tf_num_bits: 2u8,
tf_sum: 0
}
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.block_info(), BlockInfo::VInt(3u32));
assert!(!skip_reader.advance());
}
@@ -165,13 +250,60 @@ mod tests {
skip_serializer.write_doc(5u32, 5u8);
skip_serializer.data().to_owned()
};
let mut skip_reader = SkipReader::new(OwnedRead::new(buf), IndexRecordOption::Basic);
let doc_freq = 3u32 + (COMPRESSION_BLOCK_SIZE * 2) as u32;
let mut skip_reader = SkipReader::new(
ReadOnlySource::from(buf),
doc_freq,
IndexRecordOption::Basic,
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.doc(), 1u32);
assert_eq!(skip_reader.doc_num_bits(), 2u8);
assert_eq!(
skip_reader.block_info(),
BlockInfo::BitPacked {
doc_num_bits: 2u8,
tf_num_bits: 0,
tf_sum: 0u32
}
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.doc(), 5u32);
assert_eq!(skip_reader.doc_num_bits(), 5u8);
assert_eq!(
skip_reader.block_info(),
BlockInfo::BitPacked {
doc_num_bits: 5u8,
tf_num_bits: 0,
tf_sum: 0u32
}
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.block_info(), BlockInfo::VInt(3u32));
assert!(!skip_reader.advance());
}
#[test]
fn test_skip_multiple_of_block_size() {
let buf = {
let mut skip_serializer = SkipSerializer::new();
skip_serializer.write_doc(1u32, 2u8);
skip_serializer.data().to_owned()
};
let doc_freq = COMPRESSION_BLOCK_SIZE as u32;
let mut skip_reader = SkipReader::new(
ReadOnlySource::from(buf),
doc_freq,
IndexRecordOption::Basic,
);
assert!(skip_reader.advance());
assert_eq!(skip_reader.doc(), 1u32);
assert_eq!(
skip_reader.block_info(),
BlockInfo::BitPacked {
doc_num_bits: 2u8,
tf_num_bits: 0,
tf_sum: 0u32
}
);
assert!(!skip_reader.advance());
}
}

5
src/query/automaton_weight.rs
View File

@@ -51,10 +51,13 @@ where
let term_info = term_stream.value();
let mut block_segment_postings = inverted_index
.read_block_postings_from_terminfo(term_info, IndexRecordOption::Basic);
while block_segment_postings.advance() {
loop {
for &doc in block_segment_postings.docs() {
doc_bitset.insert(doc);
}
if !block_segment_postings.advance() {
break;
}
}
}
let doc_bitset = BitSetDocSet::from(doc_bitset);

5
src/query/range_query.rs
View File

@@ -300,10 +300,13 @@ impl Weight for RangeWeight {
let term_info = term_range.value();
let mut block_segment_postings = inverted_index
.read_block_postings_from_terminfo(term_info, IndexRecordOption::Basic);
while block_segment_postings.advance() {
loop {
for &doc in block_segment_postings.docs() {
doc_bitset.insert(doc);
}
if !block_segment_postings.advance() {
break;
}
}
}
let doc_bitset = BitSetDocSet::from(doc_bitset);