MeiliSearch/milli/src/search/criteria/mod.rs
2022-04-04 20:54:03 +02:00

765 lines
28 KiB
Rust

use std::borrow::Cow;
use std::collections::HashMap;
use roaring::RoaringBitmap;
use self::asc_desc::AscDesc;
use self::attribute::Attribute;
use self::exactness::Exactness;
use self::initial::Initial;
use self::proximity::Proximity;
use self::r#final::Final;
use self::typo::Typo;
use self::words::Words;
use super::query_tree::{Operation, PrimitiveQueryPart, Query, QueryKind};
use crate::search::criteria::geo::Geo;
use crate::search::{word_derivations, WordDerivationsCache};
use crate::{AscDesc as AscDescName, DocumentId, FieldId, Index, Member, Result};
mod asc_desc;
mod attribute;
mod exactness;
pub mod r#final;
mod geo;
mod initial;
mod proximity;
mod typo;
mod words;
pub trait Criterion {
fn next(&mut self, params: &mut CriterionParameters) -> Result<Option<CriterionResult>>;
}
/// The result of a call to the parent criterion.
#[derive(Debug, Clone, PartialEq)]
pub struct CriterionResult {
/// The query tree that must be used by the children criterion to fetch candidates.
query_tree: Option<Operation>,
/// The candidates that this criterion is allowed to return subsets of,
/// if None, it is up to the child to compute the candidates itself.
candidates: Option<RoaringBitmap>,
/// The candidates, coming from facet filters, that this criterion is allowed to return subsets of.
filtered_candidates: Option<RoaringBitmap>,
/// Candidates that comes from the current bucket of the initial criterion.
bucket_candidates: Option<RoaringBitmap>,
}
#[derive(Debug, PartialEq)]
pub struct CriterionParameters<'a> {
wdcache: &'a mut WordDerivationsCache,
excluded_candidates: &'a RoaringBitmap,
}
/// Either a set of candidates that defines the candidates
/// that are allowed to be returned,
/// or the candidates that must never be returned.
#[derive(Debug)]
enum Candidates {
Allowed(RoaringBitmap),
Forbidden(RoaringBitmap),
}
impl Default for Candidates {
fn default() -> Self {
Self::Forbidden(RoaringBitmap::new())
}
}
pub trait Context<'c> {
fn documents_ids(&self) -> heed::Result<RoaringBitmap>;
fn word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>>;
fn exact_word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>>;
fn word_prefix_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>>;
fn exact_word_prefix_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>>;
fn word_pair_proximity_docids(
&self,
left: &str,
right: &str,
proximity: u8,
) -> heed::Result<Option<RoaringBitmap>>;
fn word_prefix_pair_proximity_docids(
&self,
left: &str,
right: &str,
proximity: u8,
) -> heed::Result<Option<RoaringBitmap>>;
fn words_fst<'t>(&self) -> &'t fst::Set<Cow<[u8]>>;
fn in_prefix_cache(&self, word: &str) -> bool;
fn docid_words_positions(
&self,
docid: DocumentId,
) -> heed::Result<HashMap<String, RoaringBitmap>>;
fn word_position_iterator(
&self,
word: &str,
in_prefix_cache: bool,
) -> heed::Result<Box<dyn Iterator<Item = heed::Result<((&'c str, u32), RoaringBitmap)>> + 'c>>;
fn synonyms(&self, word: &str) -> heed::Result<Option<Vec<Vec<String>>>>;
fn searchable_fields_ids(&self) -> Result<Vec<FieldId>>;
fn field_id_word_count_docids(
&self,
field_id: FieldId,
word_count: u8,
) -> heed::Result<Option<RoaringBitmap>>;
fn word_position_docids(&self, word: &str, pos: u32) -> heed::Result<Option<RoaringBitmap>>;
}
pub struct CriteriaBuilder<'t> {
rtxn: &'t heed::RoTxn<'t>,
index: &'t Index,
words_fst: fst::Set<Cow<'t, [u8]>>,
words_prefixes_fst: fst::Set<Cow<'t, [u8]>>,
}
impl<'c> Context<'c> for CriteriaBuilder<'c> {
fn documents_ids(&self) -> heed::Result<RoaringBitmap> {
self.index.documents_ids(self.rtxn)
}
fn word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
self.index.word_docids.get(self.rtxn, &word)
}
fn exact_word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
self.index.exact_word_docids.get(self.rtxn, &word)
}
fn word_prefix_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
self.index.word_prefix_docids.get(self.rtxn, &word)
}
fn exact_word_prefix_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
self.index.exact_word_prefix_docids.get(self.rtxn, &word)
}
fn word_pair_proximity_docids(
&self,
left: &str,
right: &str,
proximity: u8,
) -> heed::Result<Option<RoaringBitmap>> {
let key = (left, right, proximity);
self.index.word_pair_proximity_docids.get(self.rtxn, &key)
}
fn word_prefix_pair_proximity_docids(
&self,
left: &str,
right: &str,
proximity: u8,
) -> heed::Result<Option<RoaringBitmap>> {
let key = (left, right, proximity);
self.index.word_prefix_pair_proximity_docids.get(self.rtxn, &key)
}
fn words_fst<'t>(&self) -> &'t fst::Set<Cow<[u8]>> {
&self.words_fst
}
fn in_prefix_cache(&self, word: &str) -> bool {
self.words_prefixes_fst.contains(word)
}
fn docid_words_positions(
&self,
docid: DocumentId,
) -> heed::Result<HashMap<String, RoaringBitmap>> {
let mut words_positions = HashMap::new();
for result in self.index.docid_word_positions.prefix_iter(self.rtxn, &(docid, ""))? {
let ((_, word), positions) = result?;
words_positions.insert(word.to_string(), positions);
}
Ok(words_positions)
}
fn word_position_iterator(
&self,
word: &str,
in_prefix_cache: bool,
) -> heed::Result<Box<dyn Iterator<Item = heed::Result<((&'c str, u32), RoaringBitmap)>> + 'c>>
{
let range = {
let left = u32::min_value();
let right = u32::max_value();
let left = (word, left);
let right = (word, right);
left..=right
};
let db = match in_prefix_cache {
true => self.index.word_prefix_position_docids,
false => self.index.word_position_docids,
};
Ok(Box::new(db.range(self.rtxn, &range)?))
}
fn synonyms(&self, word: &str) -> heed::Result<Option<Vec<Vec<String>>>> {
self.index.words_synonyms(self.rtxn, &[word])
}
fn searchable_fields_ids(&self) -> Result<Vec<FieldId>> {
match self.index.searchable_fields_ids(self.rtxn)? {
Some(searchable_fields_ids) => Ok(searchable_fields_ids),
None => Ok(self.index.fields_ids_map(self.rtxn)?.ids().collect()),
}
}
fn field_id_word_count_docids(
&self,
field_id: FieldId,
word_count: u8,
) -> heed::Result<Option<RoaringBitmap>> {
let key = (field_id, word_count);
self.index.field_id_word_count_docids.get(self.rtxn, &key)
}
fn word_position_docids(&self, word: &str, pos: u32) -> heed::Result<Option<RoaringBitmap>> {
let key = (word, pos);
self.index.word_position_docids.get(self.rtxn, &key)
}
}
impl<'t> CriteriaBuilder<'t> {
pub fn new(rtxn: &'t heed::RoTxn<'t>, index: &'t Index) -> Result<Self> {
let words_fst = index.words_fst(rtxn)?;
let words_prefixes_fst = index.words_prefixes_fst(rtxn)?;
Ok(Self { rtxn, index, words_fst, words_prefixes_fst })
}
pub fn build(
&'t self,
query_tree: Option<Operation>,
primitive_query: Option<Vec<PrimitiveQueryPart>>,
filtered_candidates: Option<RoaringBitmap>,
sort_criteria: Option<Vec<AscDescName>>,
) -> Result<Final<'t>> {
use crate::criterion::Criterion as Name;
let primitive_query = primitive_query.unwrap_or_default();
let mut criterion =
Box::new(Initial::new(query_tree, filtered_candidates)) as Box<dyn Criterion>;
for name in self.index.criteria(&self.rtxn)? {
criterion = match name {
Name::Words => Box::new(Words::new(self, criterion)),
Name::Typo => Box::new(Typo::new(self, criterion)),
Name::Sort => match sort_criteria {
Some(ref sort_criteria) => {
for asc_desc in sort_criteria {
criterion = match asc_desc {
AscDescName::Asc(Member::Field(field)) => Box::new(AscDesc::asc(
&self.index,
&self.rtxn,
criterion,
field.to_string(),
)?),
AscDescName::Desc(Member::Field(field)) => Box::new(AscDesc::desc(
&self.index,
&self.rtxn,
criterion,
field.to_string(),
)?),
AscDescName::Asc(Member::Geo(point)) => Box::new(Geo::asc(
&self.index,
&self.rtxn,
criterion,
point.clone(),
)?),
AscDescName::Desc(Member::Geo(point)) => Box::new(Geo::desc(
&self.index,
&self.rtxn,
criterion,
point.clone(),
)?),
};
}
criterion
}
None => criterion,
},
Name::Proximity => Box::new(Proximity::new(self, criterion)),
Name::Attribute => Box::new(Attribute::new(self, criterion)),
Name::Exactness => Box::new(Exactness::new(self, criterion, &primitive_query)?),
Name::Asc(field) => {
Box::new(AscDesc::asc(&self.index, &self.rtxn, criterion, field)?)
}
Name::Desc(field) => {
Box::new(AscDesc::desc(&self.index, &self.rtxn, criterion, field)?)
}
};
}
Ok(Final::new(self, criterion))
}
}
pub fn resolve_query_tree<'t>(
ctx: &'t dyn Context,
query_tree: &Operation,
wdcache: &mut WordDerivationsCache,
) -> Result<RoaringBitmap> {
fn resolve_operation<'t>(
ctx: &'t dyn Context,
query_tree: &Operation,
wdcache: &mut WordDerivationsCache,
) -> Result<RoaringBitmap> {
use Operation::{And, Or, Phrase, Query};
match query_tree {
And(ops) => {
let mut ops = ops
.iter()
.map(|op| resolve_operation(ctx, op, wdcache))
.collect::<Result<Vec<_>>>()?;
ops.sort_unstable_by_key(|cds| cds.len());
let mut candidates = RoaringBitmap::new();
let mut first_loop = true;
for docids in ops {
if first_loop {
candidates = docids;
first_loop = false;
} else {
candidates &= &docids;
}
}
Ok(candidates)
}
Phrase(words) => {
let mut candidates = RoaringBitmap::new();
let mut first_iter = true;
let winsize = words.len().min(7);
for win in words.windows(winsize) {
// Get all the documents with the matching distance for each word pairs.
let mut bitmaps = Vec::with_capacity(winsize.pow(2));
for (offset, s1) in win.iter().enumerate() {
for (dist, s2) in win.iter().skip(offset).enumerate() {
match ctx.word_pair_proximity_docids(s1, s2, dist as u8 + 1)? {
Some(m) => bitmaps.push(m),
// If there are no document for this distance, there will be no
// results for the phrase query.
None => return Ok(RoaringBitmap::new()),
}
}
}
// We sort the bitmaps so that we perform the small intersections first, which is faster.
bitmaps.sort_unstable_by(|a, b| a.len().cmp(&b.len()));
for bitmap in bitmaps {
if first_iter {
candidates = bitmap;
first_iter = false;
} else {
candidates &= bitmap;
}
// There will be no match, return early
if candidates.is_empty() {
break;
}
}
}
Ok(candidates)
}
Or(_, ops) => {
let mut candidates = RoaringBitmap::new();
for op in ops {
let docids = resolve_operation(ctx, op, wdcache)?;
candidates |= docids;
}
Ok(candidates)
}
Query(q) => Ok(query_docids(ctx, q, wdcache)?),
}
}
resolve_operation(ctx, query_tree, wdcache)
}
fn all_word_pair_proximity_docids<T: AsRef<str>, U: AsRef<str>>(
ctx: &dyn Context,
left_words: &[(T, u8)],
right_words: &[(U, u8)],
proximity: u8,
) -> Result<RoaringBitmap> {
let mut docids = RoaringBitmap::new();
for (left, _l_typo) in left_words {
for (right, _r_typo) in right_words {
let current_docids = ctx
.word_pair_proximity_docids(left.as_ref(), right.as_ref(), proximity)?
.unwrap_or_default();
docids |= current_docids;
}
}
Ok(docids)
}
fn query_docids(
ctx: &dyn Context,
query: &Query,
wdcache: &mut WordDerivationsCache,
) -> Result<RoaringBitmap> {
match &query.kind {
QueryKind::Exact { word, original_typo } => {
if query.prefix && ctx.in_prefix_cache(&word) {
let mut docids = ctx.word_prefix_docids(&word)?.unwrap_or_default();
// only add the exact docids if the word hasn't been derived
if *original_typo == 0 {
docids |= ctx.exact_word_prefix_docids(&word)?.unwrap_or_default();
}
Ok(docids)
} else if query.prefix {
let words = word_derivations(&word, true, 0, ctx.words_fst(), wdcache)?;
let mut docids = RoaringBitmap::new();
for (word, _typo) in words {
docids |= ctx.word_docids(&word)?.unwrap_or_default();
// only add the exact docids if the word hasn't been derived
if *original_typo == 0 {
docids |= ctx.exact_word_docids(&word)?.unwrap_or_default();
}
}
Ok(docids)
} else {
let mut docids = ctx.word_docids(&word)?.unwrap_or_default();
// only add the exact docids if the word hasn't been derived
if *original_typo == 0 {
docids |= ctx.exact_word_docids(&word)?.unwrap_or_default();
}
Ok(docids)
}
}
QueryKind::Tolerant { typo, word } => {
let words = word_derivations(&word, query.prefix, *typo, ctx.words_fst(), wdcache)?;
let mut docids = RoaringBitmap::new();
for (word, typo) in words {
let mut current_docids = ctx.word_docids(&word)?.unwrap_or_default();
if *typo == 0 {
current_docids |= ctx.exact_word_docids(&word)?.unwrap_or_default()
}
docids |= current_docids;
}
Ok(docids)
}
}
}
fn query_pair_proximity_docids(
ctx: &dyn Context,
left: &Query,
right: &Query,
proximity: u8,
wdcache: &mut WordDerivationsCache,
) -> Result<RoaringBitmap> {
if proximity >= 8 {
let mut candidates = query_docids(ctx, left, wdcache)?;
let right_candidates = query_docids(ctx, right, wdcache)?;
candidates &= right_candidates;
return Ok(candidates);
}
let prefix = right.prefix;
match (&left.kind, &right.kind) {
(QueryKind::Exact { word: left, .. }, QueryKind::Exact { word: right, .. }) => {
if prefix {
match ctx.word_prefix_pair_proximity_docids(
left.as_str(),
right.as_str(),
proximity,
)? {
Some(docids) => Ok(docids),
None => {
let r_words = word_derivations(&right, true, 0, ctx.words_fst(), wdcache)?;
all_word_pair_proximity_docids(ctx, &[(left, 0)], &r_words, proximity)
}
}
} else {
Ok(ctx
.word_pair_proximity_docids(left.as_str(), right.as_str(), proximity)?
.unwrap_or_default())
}
}
(QueryKind::Tolerant { typo, word: left }, QueryKind::Exact { word: right, .. }) => {
let l_words =
word_derivations(&left, false, *typo, ctx.words_fst(), wdcache)?.to_owned();
if prefix {
let mut docids = RoaringBitmap::new();
for (left, _) in l_words {
let current_docids = match ctx.word_prefix_pair_proximity_docids(
left.as_str(),
right.as_str(),
proximity,
)? {
Some(docids) => Ok(docids),
None => {
let r_words =
word_derivations(&right, true, 0, ctx.words_fst(), wdcache)?;
all_word_pair_proximity_docids(ctx, &[(left, 0)], &r_words, proximity)
}
}?;
docids |= current_docids;
}
Ok(docids)
} else {
all_word_pair_proximity_docids(ctx, &l_words, &[(right, 0)], proximity)
}
}
(QueryKind::Exact { word: left, .. }, QueryKind::Tolerant { typo, word: right }) => {
let r_words = word_derivations(&right, prefix, *typo, ctx.words_fst(), wdcache)?;
all_word_pair_proximity_docids(ctx, &[(left, 0)], &r_words, proximity)
}
(
QueryKind::Tolerant { typo: l_typo, word: left },
QueryKind::Tolerant { typo: r_typo, word: right },
) => {
let l_words =
word_derivations(&left, false, *l_typo, ctx.words_fst(), wdcache)?.to_owned();
let r_words = word_derivations(&right, prefix, *r_typo, ctx.words_fst(), wdcache)?;
all_word_pair_proximity_docids(ctx, &l_words, &r_words, proximity)
}
}
}
#[cfg(test)]
pub mod test {
use std::collections::HashMap;
use std::iter;
use maplit::hashmap;
use rand::rngs::StdRng;
use rand::{Rng, SeedableRng};
use super::*;
fn s(s: &str) -> String {
s.to_string()
}
pub struct TestContext<'t> {
words_fst: fst::Set<Cow<'t, [u8]>>,
word_docids: HashMap<String, RoaringBitmap>,
exact_word_docids: HashMap<String, RoaringBitmap>,
word_prefix_docids: HashMap<String, RoaringBitmap>,
exact_word_prefix_docids: HashMap<String, RoaringBitmap>,
word_pair_proximity_docids: HashMap<(String, String, i32), RoaringBitmap>,
word_prefix_pair_proximity_docids: HashMap<(String, String, i32), RoaringBitmap>,
docid_words: HashMap<u32, Vec<String>>,
}
impl<'c> Context<'c> for TestContext<'c> {
fn documents_ids(&self) -> heed::Result<RoaringBitmap> {
Ok(self.word_docids.iter().fold(RoaringBitmap::new(), |acc, (_, docids)| acc | docids))
}
fn word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
Ok(self.word_docids.get(&word.to_string()).cloned())
}
fn exact_word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
Ok(self.exact_word_docids.get(&word.to_string()).cloned())
}
fn word_prefix_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
Ok(self.word_prefix_docids.get(&word.to_string()).cloned())
}
fn exact_word_prefix_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>> {
Ok(self.exact_word_prefix_docids.get(&word.to_string()).cloned())
}
fn word_pair_proximity_docids(
&self,
left: &str,
right: &str,
proximity: u8,
) -> heed::Result<Option<RoaringBitmap>> {
let key = (left.to_string(), right.to_string(), proximity.into());
Ok(self.word_pair_proximity_docids.get(&key).cloned())
}
fn word_prefix_pair_proximity_docids(
&self,
left: &str,
right: &str,
proximity: u8,
) -> heed::Result<Option<RoaringBitmap>> {
let key = (left.to_string(), right.to_string(), proximity.into());
Ok(self.word_prefix_pair_proximity_docids.get(&key).cloned())
}
fn words_fst<'t>(&self) -> &'t fst::Set<Cow<[u8]>> {
&self.words_fst
}
fn in_prefix_cache(&self, word: &str) -> bool {
self.word_prefix_docids.contains_key(&word.to_string())
}
fn docid_words_positions(
&self,
docid: DocumentId,
) -> heed::Result<HashMap<String, RoaringBitmap>> {
if let Some(docid_words) = self.docid_words.get(&docid) {
Ok(docid_words
.iter()
.enumerate()
.map(|(i, w)| {
let bitmap = RoaringBitmap::from_sorted_iter(iter::once(i as u32)).unwrap();
(w.clone(), bitmap)
})
.collect())
} else {
Ok(HashMap::new())
}
}
fn word_position_iterator(
&self,
_word: &str,
_in_prefix_cache: bool,
) -> heed::Result<
Box<dyn Iterator<Item = heed::Result<((&'c str, u32), RoaringBitmap)>> + 'c>,
> {
todo!()
}
fn synonyms(&self, _word: &str) -> heed::Result<Option<Vec<Vec<String>>>> {
todo!()
}
fn searchable_fields_ids(&self) -> Result<Vec<FieldId>> {
todo!()
}
fn word_position_docids(
&self,
_word: &str,
_pos: u32,
) -> heed::Result<Option<RoaringBitmap>> {
todo!()
}
fn field_id_word_count_docids(
&self,
_field_id: FieldId,
_word_count: u8,
) -> heed::Result<Option<RoaringBitmap>> {
todo!()
}
}
impl<'a> Default for TestContext<'a> {
fn default() -> TestContext<'a> {
let mut rng = StdRng::seed_from_u64(102);
let rng = &mut rng;
fn random_postings<R: Rng>(rng: &mut R, len: usize) -> RoaringBitmap {
let mut values = Vec::<u32>::with_capacity(len);
while values.len() != len {
values.push(rng.gen());
}
values.sort_unstable();
RoaringBitmap::from_sorted_iter(values.into_iter()).unwrap()
}
let word_docids = hashmap! {
s("hello") => random_postings(rng, 1500),
s("hi") => random_postings(rng, 4000),
s("word") => random_postings(rng, 2500),
s("split") => random_postings(rng, 400),
s("ngrams") => random_postings(rng, 1400),
s("world") => random_postings(rng, 15_000),
s("earth") => random_postings(rng, 8000),
s("2021") => random_postings(rng, 100),
s("2020") => random_postings(rng, 500),
s("is") => random_postings(rng, 50_000),
s("this") => random_postings(rng, 50_000),
s("good") => random_postings(rng, 1250),
s("morning") => random_postings(rng, 125),
};
let exact_word_docids = HashMap::new();
let mut docid_words = HashMap::new();
for (word, docids) in word_docids.iter() {
for docid in docids {
let words = docid_words.entry(docid).or_insert(vec![]);
words.push(word.clone());
}
}
let word_prefix_docids = hashmap! {
s("h") => &word_docids[&s("hello")] | &word_docids[&s("hi")],
s("wor") => &word_docids[&s("word")] | &word_docids[&s("world")],
s("20") => &word_docids[&s("2020")] | &word_docids[&s("2021")],
};
let exact_word_prefix_docids = HashMap::new();
let mut word_pair_proximity_docids = HashMap::new();
let mut word_prefix_pair_proximity_docids = HashMap::new();
for (lword, lcandidates) in &word_docids {
for (rword, rcandidates) in &word_docids {
if lword == rword {
continue;
}
let candidates = lcandidates & rcandidates;
for candidate in candidates {
if let Some(docid_words) = docid_words.get(&candidate) {
let lposition = docid_words.iter().position(|w| w == lword).unwrap();
let rposition = docid_words.iter().position(|w| w == rword).unwrap();
let key = if lposition < rposition {
(s(lword), s(rword), (rposition - lposition) as i32)
} else {
(s(lword), s(rword), (lposition - rposition + 1) as i32)
};
let docids = word_pair_proximity_docids
.entry(key)
.or_insert(RoaringBitmap::new());
docids.push(candidate);
}
}
}
for (pword, pcandidates) in &word_prefix_docids {
if lword.starts_with(pword) {
continue;
}
let candidates = lcandidates & pcandidates;
for candidate in candidates {
if let Some(docid_words) = docid_words.get(&candidate) {
let lposition = docid_words.iter().position(|w| w == lword).unwrap();
let rposition =
docid_words.iter().position(|w| w.starts_with(pword)).unwrap();
let key = if lposition < rposition {
(s(lword), s(pword), (rposition - lposition) as i32)
} else {
(s(lword), s(pword), (lposition - rposition + 1) as i32)
};
let docids = word_prefix_pair_proximity_docids
.entry(key)
.or_insert(RoaringBitmap::new());
docids.push(candidate);
}
}
}
}
let mut keys = word_docids.keys().collect::<Vec<_>>();
keys.sort_unstable();
let words_fst = fst::Set::from_iter(keys).unwrap().map_data(|v| Cow::Owned(v)).unwrap();
TestContext {
words_fst,
word_docids,
exact_word_docids,
word_prefix_docids,
exact_word_prefix_docids,
word_pair_proximity_docids,
word_prefix_pair_proximity_docids,
docid_words,
}
}
}
}