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Merge pull request #156 from meilisearch/stop-words

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Stop words
This commit is contained in:
Clément Renault 2021-04-14 17:33:06 +02:00 committed by GitHub
commit c2df51aa95
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GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 37 additions and 49 deletions
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9
milli/src/search/mod.rs
View File

@ -91,7 +91,14 @@ impl<'a> Search<'a> {
let mut builder = QueryTreeBuilder::new(self.rtxn, self.index);
builder.optional_words(self.optional_words);
builder.authorize_typos(self.authorize_typos);
let analyzer = Analyzer::<Vec<u8>>::new(AnalyzerConfig::default());
// We make sure that the analyzer is aware of the stop words
// this ensures that the query builder is able to properly remove them.
let mut config = AnalyzerConfig::default();
let stop_words = self.index.stop_words(self.rtxn)?;
if let Some(ref stop_words) = stop_words {
config.stop_words(stop_words);
}
let analyzer = Analyzer::new(config);
let result = analyzer.analyze(query);
let tokens = result.tokens();
builder.build(tokens)?

70
milli/src/search/query_tree.rs
View File

@ -155,10 +155,6 @@ impl fmt::Debug for Query {
trait Context {
fn word_docids(&self, word: &str) -> heed::Result<Option<RoaringBitmap>>;
fn stop_words(&self) -> anyhow::Result<Option<Set<&[u8]>>>;
fn is_stop_word(&self, word: &str) -> anyhow::Result<bool> {
Ok(self.stop_words()?.map_or(false, |s| s.contains(word)))
}
fn synonyms<S: AsRef<str>>(&self, words: &[S]) -> heed::Result<Option<Vec<Vec<String>>>>;
fn word_documents_count(&self, word: &str) -> heed::Result<Option<u64>> {
match self.word_docids(word)? {
@ -188,10 +184,6 @@ impl<'a> Context for QueryTreeBuilder<'a> {
fn synonyms<S: AsRef<str>>(&self, _words: &[S]) -> heed::Result<Option<Vec<Vec<String>>>> {
Ok(None)
}
fn stop_words(&self) -> anyhow::Result<Option<Set<&[u8]>>> {
self.index.stop_words(self.rtxn)
}
}
impl<'a> QueryTreeBuilder<'a> {
@ -229,7 +221,8 @@ impl<'a> QueryTreeBuilder<'a> {
/// forcing all query words to match documents without any typo
/// (the criterion `typo` will be ignored)
pub fn build(&self, query: TokenStream) -> anyhow::Result<Option<Operation>> {
let primitive_query = create_primitive_query(query);
let stop_words = self.index.stop_words(self.rtxn)?;
let primitive_query = create_primitive_query(query, stop_words);
if !primitive_query.is_empty() {
create_query_tree(self, self.optional_words, self.authorize_typos, primitive_query).map(Some)
} else {
@ -340,7 +333,8 @@ fn create_query_tree(
optional_words: bool,
authorize_typos: bool,
query: PrimitiveQuery,
) -> anyhow::Result<Operation> {
) -> anyhow::Result<Operation>
{
/// Matches on the `PrimitiveQueryPart` and create an operation from it.
fn resolve_primitive_part(
ctx: &impl Context,
@ -358,12 +352,7 @@ fn create_query_tree(
if let Some(child) = split_best_frequency(ctx, &word)? {
children.push(child);
}
let is_stop_word = ctx.is_stop_word(&word)?;
let query = Query { prefix, kind: typos(word, authorize_typos) };
if query.prefix || query.kind.is_tolerant() || !is_stop_word {
children.push(Operation::Query(query));
}
children.push(Operation::Query(Query { prefix, kind: typos(word, authorize_typos) }));
Ok(Operation::or(false, children))
},
// create a CONSECUTIVE operation wrapping all word in the phrase
@ -378,7 +367,8 @@ fn create_query_tree(
ctx: &impl Context,
authorize_typos: bool,
query: &[PrimitiveQueryPart],
) -> anyhow::Result<Operation> {
) -> anyhow::Result<Operation>
{
const MAX_NGRAM: usize = 3;
let mut op_children = Vec::new();
@ -393,31 +383,23 @@ fn create_query_tree(
match group {
[part] => {
let operation =
resolve_primitive_part(ctx, authorize_typos, part.clone())?;
let operation = resolve_primitive_part(ctx, authorize_typos, part.clone())?;
and_op_children.push(operation);
}
},
words => {
let is_prefix = words.last().map_or(false, |part| part.is_prefix());
let words: Vec<_> = words
.iter()
.filter_map(|part| {
if let PrimitiveQueryPart::Word(word, _) = part {
Some(word.as_str())
} else {
None
}
})
.collect();
let words: Vec<_> = words.iter().filter_map(|part| {
if let PrimitiveQueryPart::Word(word, _) = part {
Some(word.as_str())
} else {
None
}
}).collect();
let mut operations = synonyms(ctx, &words)?.unwrap_or_default();
let concat = words.concat();
let is_stop_word = ctx.is_stop_word(&concat)?;
let query = Query { prefix: is_prefix, kind: typos(concat, authorize_typos) };
if query.prefix || query.kind.is_tolerant() || !is_stop_word {
operations.push(Operation::Query(query));
and_op_children.push(Operation::or(false, operations));
}
operations.push(Operation::Query(query));
and_op_children.push(Operation::or(false, operations));
}
}
@ -494,7 +476,7 @@ impl PrimitiveQueryPart {
/// Create primitive query from tokenized query string,
/// the primitive query is an intermediate state to build the query tree.
fn create_primitive_query(query: TokenStream) -> PrimitiveQuery {
fn create_primitive_query(query: TokenStream, stop_words: Option<Set<&[u8]>>) -> PrimitiveQuery {
let mut primitive_query = Vec::new();
let mut phrase = Vec::new();
let mut quoted = false;
@ -502,14 +484,16 @@ fn create_primitive_query(query: TokenStream) -> PrimitiveQuery {
let mut peekable = query.peekable();
while let Some(token) = peekable.next() {
match token.kind {
TokenKind::Word => {
TokenKind::Word | TokenKind::StopWord => {
// 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 we push it as a non-prefix word,
// 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.push(token.word.to_string());
} else if peekable.peek().is_some() {
primitive_query.push(PrimitiveQueryPart::Word(token.word.to_string(), false));
if !stop_words.as_ref().map_or(false, |swords| swords.contains(token.word.as_ref())) {
primitive_query.push(PrimitiveQueryPart::Word(token.word.to_string(), false));
}
} else {
primitive_query.push(PrimitiveQueryPart::Word(token.word.to_string(), true));
}
@ -583,7 +567,7 @@ mod test {
query: TokenStream,
) -> anyhow::Result<Option<Operation>>
{
let primitive_query = create_primitive_query(query);
let primitive_query = create_primitive_query(query, None);
if !primitive_query.is_empty() {
create_query_tree(self, optional_words, authorize_typos, primitive_query).map(Some)
} else {
@ -601,10 +585,6 @@ mod test {
let words: Vec<_> = words.iter().map(|s| s.as_ref().to_owned()).collect();
Ok(self.synonyms.get(&words).cloned())
}
fn stop_words(&self) -> anyhow::Result<Option<Set<&[u8]>>> {
Ok(None)
}
}
impl Default for TestContext {

7
milli/src/update/settings.rs
View File

@ -602,12 +602,13 @@ mod tests {
assert_eq!(stop_words.as_fst().as_bytes(), expected.as_fst().as_bytes());
// when we search for something that is a non prefix stop_words it should be ignored
// thus we should get a placeholder search (all the results = 3)
let result = index.search(&rtxn).query("the ").execute().unwrap();
assert!(result.documents_ids.is_empty());
assert_eq!(result.documents_ids.len(), 3);
let result = index.search(&rtxn).query("i ").execute().unwrap();
assert!(result.documents_ids.is_empty());
assert_eq!(result.documents_ids.len(), 3);
let result = index.search(&rtxn).query("are ").execute().unwrap();
assert!(result.documents_ids.is_empty());
assert_eq!(result.documents_ids.len(), 3);
let result = index.search(&rtxn).query("dog").execute().unwrap();
assert_eq!(result.documents_ids.len(), 2); // we have two maxims talking about doggos