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Merge branch 'search-refactor-located-query-terms' into search-refactor

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This commit is contained in:
Loïc Lecrenier 2023-04-03 10:04:36 +02:00
commit 55fbfb6124
4 changed files with 203 additions and 87 deletions
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18
milli/src/search/new/limits.rs Normal file
View File

@ -0,0 +1,18 @@
/// Maximum number of tokens we consider in a single search.
// TODO: Loic, find proper value here so we don't overflow the interner.
pub const MAX_TOKEN_COUNT: usize = 1_000;
/// Maximum number of prefixes that can be derived from a single word.
pub const MAX_PREFIX_COUNT: usize = 1_000;
/// Maximum number of words that can be derived from a single word with a distance of one to that word.
pub const MAX_ONE_TYPO_COUNT: usize = 150;
/// Maximum number of words that can be derived from a single word with a distance of two to that word.
pub const MAX_TWO_TYPOS_COUNT: usize = 50;
/// Maximum amount of synonym phrases that can be derived from a single word.
pub const MAX_SYNONYM_PHRASE_COUNT: usize = 50;
/// Maximum amount of words inside of all the synonym phrases that can be derived from a single word.
///
/// This limit is meant to gracefully handle the case where a word would have very long phrases as synonyms.
pub const MAX_SYNONYM_WORD_COUNT: usize = 100;

1
milli/src/search/new/mod.rs
View File

@ -2,6 +2,7 @@ mod db_cache;
mod distinct;
mod graph_based_ranking_rule;
mod interner;
mod limits;
mod logger;
mod query_graph;
mod query_term;

18
milli/src/search/new/query_graph.rs
View File

@ -254,28 +254,28 @@ impl QueryGraph {
}
for node_id in self.nodes.indexes() {
let node = self.nodes.get(node_id);
let end_position = match &node.data {
QueryNodeData::Term(term) => *term.positions.end(),
let end_prev_term_id = match &node.data {
QueryNodeData::Term(term) => *term.term_ids.end() as i16,
QueryNodeData::Start => -1,
QueryNodeData::Deleted => continue,
QueryNodeData::End => continue,
};
let successors = {
let mut successors = SmallBitmap::for_interned_values_in(&self.nodes);
let mut min = i8::MAX;
let mut min = i16::MAX;
for (node_id, node) in self.nodes.iter() {
let start_position = match &node.data {
QueryNodeData::Term(term) => *term.positions.start(),
QueryNodeData::End => i8::MAX,
let start_next_term_id = match &node.data {
QueryNodeData::Term(term) => *term.term_ids.start() as i16,
QueryNodeData::End => i16::MAX,
QueryNodeData::Start => continue,
QueryNodeData::Deleted => continue,
};
if start_position <= end_position {
if start_next_term_id <= end_prev_term_id {
continue;
}
match start_position.cmp(&min) {
match start_next_term_id.cmp(&min) {
Ordering::Less => {
min = start_position;
min = start_next_term_id;
successors.clear();
successors.insert(node_id);
}

239
milli/src/search/new/query_term.rs
View File

@ -1,7 +1,6 @@
use std::borrow::Cow;
use std::collections::BTreeSet;
use std::mem;
use std::ops::RangeInclusive;
use std::ops::{ControlFlow, RangeInclusive};
use charabia::normalizer::NormalizedTokenIter;
use charabia::{SeparatorKind, TokenKind};
@ -12,7 +11,7 @@ use heed::RoTxn;
use itertools::Itertools;
use super::interner::{DedupInterner, Interned};
use super::SearchContext;
use super::{limits, SearchContext};
use crate::search::fst_utils::{Complement, Intersection, StartsWith, Union};
use crate::search::{build_dfa, get_first};
use crate::{CboRoaringBitmapLenCodec, Index, Result, MAX_WORD_LENGTH};
@ -135,7 +134,7 @@ pub struct QueryTermSubset {
#[derive(Clone, PartialEq, Eq, Hash)]
pub struct LocatedQueryTermSubset {
pub term_subset: QueryTermSubset,
pub positions: RangeInclusive<i8>,
pub positions: RangeInclusive<u16>,
pub term_ids: RangeInclusive<u8>,
}
@ -418,7 +417,7 @@ fn find_zero_typo_prefix_derivations(
word_interned: Interned<String>,
fst: fst::Set<Cow<[u8]>>,
word_interner: &mut DedupInterner<String>,
mut visit: impl FnMut(Interned<String>) -> Result<()>,
mut visit: impl FnMut(Interned<String>) -> Result<ControlFlow<()>>,
) -> Result<()> {
let word = word_interner.get(word_interned).to_owned();
let word = word.as_str();
@ -429,7 +428,10 @@ fn find_zero_typo_prefix_derivations(
let derived_word = std::str::from_utf8(derived_word)?.to_owned();
let derived_word_interned = word_interner.insert(derived_word);
if derived_word_interned != word_interned {
visit(derived_word_interned)?;
let cf = visit(derived_word_interned)?;
if cf.is_break() {
break;
}
}
}
Ok(())
@ -440,7 +442,7 @@ fn find_zero_one_typo_derivations(
is_prefix: bool,
fst: fst::Set<Cow<[u8]>>,
word_interner: &mut DedupInterner<String>,
mut visit: impl FnMut(Interned<String>, ZeroOrOneTypo) -> Result<()>,
mut visit: impl FnMut(Interned<String>, ZeroOrOneTypo) -> Result<ControlFlow<()>>,
) -> Result<()> {
let word = word_interner.get(word_interned).to_owned();
let word = word.as_str();
@ -448,7 +450,6 @@ fn find_zero_one_typo_derivations(
let dfa = build_dfa(word, 1, is_prefix);
let starts = StartsWith(Str::new(get_first(word)));
let mut stream = fst.search_with_state(Intersection(starts, &dfa)).into_stream();
// TODO: There may be wayyy too many matches (e.g. in the thousands), how to reduce them?
while let Some((derived_word, state)) = stream.next() {
let derived_word = std::str::from_utf8(derived_word)?;
@ -457,13 +458,21 @@ fn find_zero_one_typo_derivations(
match d.to_u8() {
0 => {
if derived_word != word_interned {
visit(derived_word, ZeroOrOneTypo::Zero)?;
let cf = visit(derived_word, ZeroOrOneTypo::Zero)?;
if cf.is_break() {
break;
}
}
}
1 => {
visit(derived_word, ZeroOrOneTypo::One)?;
let cf = visit(derived_word, ZeroOrOneTypo::One)?;
if cf.is_break() {
break;
}
}
_ => {
unreachable!("One typo dfa produced multiple typos")
}
_ => panic!(),
}
}
Ok(())
@ -480,7 +489,7 @@ fn find_zero_one_two_typo_derivations(
is_prefix: bool,
fst: fst::Set<Cow<[u8]>>,
word_interner: &mut DedupInterner<String>,
mut visit: impl FnMut(Interned<String>, NumberOfTypos) -> Result<()>,
mut visit: impl FnMut(Interned<String>, NumberOfTypos) -> Result<ControlFlow<()>>,
) -> Result<()> {
let word = word_interner.get(word_interned).to_owned();
let word = word.as_str();
@ -492,7 +501,6 @@ fn find_zero_one_two_typo_derivations(
let automaton = Union(first, &second);
let mut stream = fst.search_with_state(automaton).into_stream();
// TODO: There may be wayyy too many matches (e.g. in the thousands), how to reduce them?
while let Some((derived_word, state)) = stream.next() {
let derived_word = std::str::from_utf8(derived_word)?;
@ -500,7 +508,10 @@ fn find_zero_one_two_typo_derivations(
// in the case the typo is on the first letter, we know the number of typo
// is two
if get_first(derived_word) != get_first(word) {
visit(derived_word_interned, NumberOfTypos::Two)?;
let cf = visit(derived_word_interned, NumberOfTypos::Two)?;
if cf.is_break() {
break;
}
} else {
// Else, we know that it is the second dfa that matched and compute the
// correct distance
@ -508,16 +519,25 @@ fn find_zero_one_two_typo_derivations(
match d.to_u8() {
0 => {
if derived_word_interned != word_interned {
visit(derived_word_interned, NumberOfTypos::Zero)?;
let cf = visit(derived_word_interned, NumberOfTypos::Zero)?;
if cf.is_break() {
break;
}
}
}
1 => {
visit(derived_word_interned, NumberOfTypos::One)?;
let cf = visit(derived_word_interned, NumberOfTypos::One)?;
if cf.is_break() {
break;
}
}
2 => {
visit(derived_word_interned, NumberOfTypos::Two)?;
let cf = visit(derived_word_interned, NumberOfTypos::Two)?;
if cf.is_break() {
break;
}
_ => panic!(),
}
_ => unreachable!("2 typos DFA produced a distance greater than 2"),
}
}
}
@ -560,21 +580,30 @@ fn partially_initialized_term_from_word(
fst,
&mut ctx.word_interner,
|derived_word| {
if prefix_of.len() < limits::MAX_PREFIX_COUNT {
prefix_of.insert(derived_word);
Ok(())
Ok(ControlFlow::Continue(()))
} else {
Ok(ControlFlow::Break(()))
}
},
)?;
}
let synonyms = ctx.index.synonyms(ctx.txn)?;
let mut synonym_word_count = 0;
let synonyms = synonyms
.get(&vec![word.to_owned()])
.cloned()
.unwrap_or_default()
.into_iter()
.map(|words| {
.take(limits::MAX_SYNONYM_PHRASE_COUNT)
.filter_map(|words| {
if synonym_word_count + words.len() > limits::MAX_SYNONYM_WORD_COUNT {
return None;
}
synonym_word_count += words.len();
let words = words.into_iter().map(|w| Some(ctx.word_interner.insert(w))).collect();
ctx.phrase_interner.insert(Phrase { words })
Some(ctx.phrase_interner.insert(Phrase { words }))
})
.collect();
let zero_typo = ZeroTypoTerm { phrase: None, zero_typo, prefix_of, synonyms, use_prefix_db };
@ -629,10 +658,14 @@ impl QueryTerm {
match nbr_typos {
ZeroOrOneTypo::Zero => {}
ZeroOrOneTypo::One => {
if one_typo_words.len() < limits::MAX_ONE_TYPO_COUNT {
one_typo_words.insert(derived_word);
} else {
return Ok(ControlFlow::Break(()));
}
}
Ok(())
}
Ok(ControlFlow::Continue(()))
},
)?;
let split_words =
@ -664,16 +697,26 @@ impl QueryTerm {
index.words_fst(txn)?,
word_interner,
|derived_word, nbr_typos| {
if one_typo_words.len() >= limits::MAX_ONE_TYPO_COUNT
&& two_typo_words.len() >= limits::MAX_TWO_TYPOS_COUNT
{
// No chance we will add either one- or two-typo derivations anymore, stop iterating.
return Ok(ControlFlow::Break(()));
}
match nbr_typos {
NumberOfTypos::Zero => {}
NumberOfTypos::One => {
if one_typo_words.len() < limits::MAX_ONE_TYPO_COUNT {
one_typo_words.insert(derived_word);
}
}
NumberOfTypos::Two => {
if two_typo_words.len() < limits::MAX_TWO_TYPOS_COUNT {
two_typo_words.insert(derived_word);
}
}
Ok(())
}
Ok(ControlFlow::Continue(()))
},
)?;
let split_words =
@ -733,13 +776,66 @@ impl QueryTerm {
/// A query term term coupled with its position in the user's search query.
#[derive(Clone)]
pub struct LocatedQueryTerm {
// should the query term subset really be interned?
// possibly, yes
pub value: Interned<QueryTerm>,
pub positions: RangeInclusive<i8>,
pub positions: RangeInclusive<u16>,
}
impl LocatedQueryTerm {
/// Return `true` iff the term is empty
pub fn is_empty(&self, interner: &DedupInterner<QueryTerm>) -> bool {
interner.get(self.value).is_empty()
}
}
struct PhraseBuilder {
words: Vec<Option<Interned<String>>>,
start: u16,
end: u16,
}
impl PhraseBuilder {
fn empty() -> Self {
Self { words: Default::default(), start: u16::MAX, end: u16::MAX }
}
fn is_empty(&self) -> bool {
self.words.is_empty()
}
// precondition: token has kind Word or StopWord
fn push_word(&mut self, ctx: &mut SearchContext, token: &charabia::Token, position: u16) {
if self.is_empty() {
self.start = position;
}
self.end = position;
if let TokenKind::StopWord = token.kind {
self.words.push(None);
} else {
// token has kind Word
let word = ctx.word_interner.insert(token.lemma().to_string());
// TODO: in a phrase, check that every word exists
// otherwise return an empty term
self.words.push(Some(word));
}
}
fn build(self, ctx: &mut SearchContext) -> Option<LocatedQueryTerm> {
if self.is_empty() {
return None;
}
Some(LocatedQueryTerm {
value: ctx.term_interner.push(QueryTerm::phrase(
&mut ctx.word_interner,
&mut ctx.phrase_interner,
Phrase { words: self.words },
)),
positions: self.start..=self.end,
})
}
}
/// Convert the tokenised search query into a list of located query terms.
// TODO: checking if the positions are correct for phrases, separators, ngrams
pub fn located_query_terms_from_string(
ctx: &mut SearchContext,
query: NormalizedTokenIter<&[u8]>,
@ -749,16 +845,14 @@ pub fn located_query_terms_from_string(
let mut located_terms = Vec::new();
let mut phrase = Vec::new();
let mut quoted = false;
let mut phrase: Option<PhraseBuilder> = None;
let parts_limit = words_limit.unwrap_or(usize::MAX);
let mut position = -1i8;
let mut phrase_start = -1i8;
let mut phrase_end = -1i8;
// start with the last position as we will wrap around to position 0 at the beginning of the loop below.
let mut position = u16::MAX;
let mut peekable = query.peekable();
let mut peekable = query.take(super::limits::MAX_TOKEN_COUNT).peekable();
while let Some(token) = peekable.next() {
// early return if word limit is exceeded
if located_terms.len() >= parts_limit {
@ -767,23 +861,14 @@ pub fn located_query_terms_from_string(
match token.kind {
TokenKind::Word | TokenKind::StopWord => {
position += 1;
// On first loop, goes from u16::MAX to 0, then normal increment.
position = position.wrapping_add(1);
// 1. if the word is quoted we push it in a phrase-buffer waiting for the ending quote,
// 2. if the word is not the last token of the query and is not a stop_word we push it as a non-prefix word,
// 3. if the word is the last token of the query we push it as a prefix word.
if quoted {
phrase_end = position;
if phrase.is_empty() {
phrase_start = position;
}
if let TokenKind::StopWord = token.kind {
phrase.push(None);
} else {
let word = ctx.word_interner.insert(token.lemma().to_string());
// TODO: in a phrase, check that every word exists
// otherwise return an empty term
phrase.push(Some(word));
}
if let Some(phrase) = &mut phrase {
phrase.push_word(ctx, &token, position)
} else if peekable.peek().is_some() {
match token.kind {
TokenKind::Word => {
@ -822,41 +907,53 @@ pub fn located_query_terms_from_string(
position += 0;
}
}
let quote_count = token.lemma().chars().filter(|&s| s == '"').count();
// swap quoted state if we encounter a double quote
if quote_count % 2 != 0 {
quoted = !quoted;
phrase = 'phrase: {
let phrase = phrase.take();
// If we have a hard separator inside a phrase, we immediately start a new phrase
let phrase = if separator_kind == SeparatorKind::Hard {
if let Some(phrase) = phrase {
if let Some(located_query_term) = phrase.build(ctx) {
located_terms.push(located_query_term)
}
// if there is a quote or a hard separator we close the phrase.
if !phrase.is_empty() && (quote_count > 0 || separator_kind == SeparatorKind::Hard)
{
let located_query_term = LocatedQueryTerm {
value: ctx.term_interner.push(QueryTerm::phrase(
&mut ctx.word_interner,
&mut ctx.phrase_interner,
Phrase { words: mem::take(&mut phrase) },
)),
positions: phrase_start..=phrase_end,
Some(PhraseBuilder::empty())
} else {
None
}
} else {
phrase
};
located_terms.push(located_query_term);
// We close and start a new phrase depending on the number of double quotes
let mut quote_count = token.lemma().chars().filter(|&s| s == '"').count();
if quote_count == 0 {
break 'phrase phrase;
}
// Consume the closing quote and the phrase
if let Some(phrase) = phrase {
// Per the check above, quote_count > 0
quote_count -= 1;
if let Some(located_query_term) = phrase.build(ctx) {
located_terms.push(located_query_term)
}
}
// Start new phrase if the token ends with an opening quote
(quote_count % 2 == 1).then_some(PhraseBuilder::empty())
};
}
_ => (),
}
}
// If a quote is never closed, we consider all of the end of the query as a phrase.
if !phrase.is_empty() {
let located_query_term = LocatedQueryTerm {
value: ctx.term_interner.push(QueryTerm::phrase(
&mut ctx.word_interner,
&mut ctx.phrase_interner,
Phrase { words: mem::take(&mut phrase) },
)),
positions: phrase_start..=phrase_end,
};
if let Some(phrase) = phrase.take() {
if let Some(located_query_term) = phrase.build(ctx) {
located_terms.push(located_query_term);
}
}
Ok(located_terms)
}