setting up facets

meilisearch-core/Cargo.toml

@@ -11,8 +11,10 @@ bincode = "1.2.1"
 byteorder = "1.3.4"
 chrono = { version = "0.4.11", features = ["serde"] }
 compact_arena = "0.4.0"
+cow-utils = "0.1.2"
 crossbeam-channel = "0.4.2"
 deunicode = "1.1.0"
+either = "1.5.3"
 env_logger = "0.7.1"
 fst = { version = "0.3.5", default-features = false }
 hashbrown = { version = "0.7.1", features = ["serde"] }

meilisearch-core/src/error.rs

@@ -28,7 +28,8 @@ pub enum Error {
     Serializer(SerializerError),
     Deserializer(DeserializerError),
     UnsupportedOperation(UnsupportedOperation),
-    FilterParseError(PestError<Rule>)
+    FilterParseError(PestError<Rule>),
+    FacetError(FacetError),
 }
 
 impl From<io::Error> for Error {
@@ -57,7 +58,13 @@ impl From<PestError<Rule>> for Error {
             s.to_string()
         }))
     }
-} 
+}
+
+impl From<FacetError> for Error {
+    fn from(error: FacetError) -> Error {
+        Error::FacetError(error)
+    }
+}
 
 impl From<meilisearch_schema::Error> for Error {
     fn from(error: meilisearch_schema::Error) -> Error {
@@ -127,6 +134,7 @@ impl fmt::Display for Error {
             Deserializer(e) => write!(f, "deserializer error; {}", e),
             UnsupportedOperation(op) => write!(f, "unsupported operation; {}", op),
             FilterParseError(e) => write!(f, "error parsing filter; {}", e),
+            FacetError(e) => write!(f, "error processing facet filter: {}", e),
         }
     }
 }
@@ -156,3 +164,40 @@ impl fmt::Display for UnsupportedOperation {
         }
     }
 }
+
+#[derive(Debug)]
+pub enum FacetError {
+    EmptyArray,
+    ParsingError(String),
+    UnexpectedToken { expected: &'static [&'static str], found: String },
+    InvalidFormat(String),
+    AttributeNotFound(String),
+    AttributeNotSet { expected: Vec<String>, found: String },
+    InvalidDocumentAttribute(String),
+}
+
+impl FacetError {
+    pub fn unexpected_token(expected: &'static [&'static str], found: impl ToString) -> FacetError {
+        FacetError::UnexpectedToken{ expected, found: found.to_string() }
+    }
+
+    pub fn attribute_not_set(expected: Vec<String>, found: impl ToString) -> FacetError {
+        FacetError::AttributeNotSet{ expected, found: found.to_string() }
+    }
+}
+
+impl fmt::Display for FacetError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        use FacetError::*;
+
+        match self {
+            EmptyArray => write!(f, "empty array in facet filter is unspecified behavior"),
+            ParsingError(msg) => write!(f, "parsing error: {}", msg),
+            UnexpectedToken { expected, found } => write!(f, "unexpected token {}, expected {}", found, expected.join("or")),
+            InvalidFormat(found) => write!(f, "invalid facet: {}, facets should be \"facetName:facetValue\"", found),
+            AttributeNotFound(attr) => write!(f, "unknown {:?} attribute", attr),
+            AttributeNotSet { found, expected } => write!(f, "`{}` is not set as a faceted attribute. available facet attributes: {}", found, expected.join(", ")),
+            InvalidDocumentAttribute(attr) => write!(f, "invalid document attribute {}, accepted types: string and [string]", attr),
+        }
+    }
+}

meilisearch-core/src/facets.rs

@@ -0,0 +1,353 @@
+use std::borrow::Cow;
+use std::collections::HashMap;
+use std::hash::Hash;
+use std::ops::Deref;
+
+use cow_utils::CowUtils;
+use either::Either;
+use heed::types::{Str, OwnedType};
+use indexmap::IndexMap;
+use serde_json::Value;
+
+use meilisearch_schema::{FieldId, Schema};
+use meilisearch_types::DocumentId;
+
+use crate::database::MainT;
+use crate::error::{FacetError, Error};
+use crate::store::BEU16;
+
+/// Data structure used to represent a boolean expression in the form of nested arrays.
+/// Values in the outer array are and-ed together, values in the inner arrays are or-ed together.
+#[derive(Debug, PartialEq)]
+pub struct FacetFilter(Vec<Either<Vec<FacetKey>, FacetKey>>);
+
+impl Deref for FacetFilter {
+    type Target = Vec<Either<Vec<FacetKey>, FacetKey>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl FacetFilter {
+    pub fn from_str(
+        s: &str,
+        schema: &Schema,
+        attributes_for_faceting: &[FieldId],
+    ) -> Result<Self, FacetError> {
+
+        let parsed = serde_json::from_str::<Value>(s).map_err(|e| FacetError::ParsingError(e.to_string()))?;
+        let mut filter = Vec::new();
+        match parsed {
+            Value::Array(and_exprs) => {
+                if and_exprs.is_empty() {
+                    return Err(FacetError::EmptyArray);
+                }
+                for expr in and_exprs {
+                    match expr {
+                        Value::String(s) => {
+                            let key = FacetKey::from_str( &s, schema, attributes_for_faceting)?;
+                            filter.push(Either::Right(key));
+                        }
+                        Value::Array(or_exprs) => {
+                            if or_exprs.is_empty() {
+                                return Err(FacetError::EmptyArray);
+                            }
+                            let mut inner = Vec::new();
+                            for expr in or_exprs {
+                                match expr {
+                                    Value::String(s) => {
+                                        let key = FacetKey::from_str( &s, schema, attributes_for_faceting)?;
+                                        inner.push(key);
+                                    }
+                                    bad_value => return Err(FacetError::unexpected_token(&["String"], bad_value)),
+                                }
+                            }
+                            filter.push(Either::Left(inner));
+                        }
+                        bad_value => return Err(FacetError::unexpected_token(&["Array", "String"], bad_value)),
+                    }
+                }
+                return Ok(Self(filter));
+            }
+            bad_value => Err(FacetError::unexpected_token(&["String"], bad_value)),
+        }
+    }
+}
+
+#[derive(Debug, Eq, PartialEq, Hash)]
+#[repr(C)]
+pub struct FacetKey(FieldId, String);
+
+impl FacetKey {
+    pub fn new(field_id: FieldId, value: String) -> Self {
+        let value = match value.cow_to_lowercase() {
+                Cow::Borrowed(_) => value,
+                Cow::Owned(s) => s,
+        };
+        Self(field_id, value)
+    }
+
+    pub fn key(&self) -> FieldId {
+        self.0
+    }
+
+    pub fn value(&self) -> &str {
+        &self.1
+    }
+
+    // TODO improve parser
+    fn from_str(
+        s: &str,
+        schema: &Schema,
+        attributes_for_faceting: &[FieldId],
+    ) -> Result<Self, FacetError> {
+        let mut split = s.splitn(2, ':');
+        let key = split
+            .next()
+            .ok_or_else(|| FacetError::InvalidFormat(s.to_string()))?
+            .trim();
+        let field_id = schema
+            .id(key)
+            .ok_or_else(|| FacetError::AttributeNotFound(key.to_string()))?;
+
+        if !attributes_for_faceting.contains(&field_id) {
+            return Err(FacetError::attribute_not_set(
+                    attributes_for_faceting
+                    .iter()
+                    .filter_map(|&id| schema.name(id))
+                    .map(str::to_string)
+                    .collect::<Vec<_>>(),
+                    key))
+        }
+        let value = split
+            .next()
+            .ok_or_else(|| FacetError::InvalidFormat(s.to_string()))?
+            .trim();
+        // unquoting the string if need be:
+        let mut indices = value.char_indices();
+        let value =  match (indices.next(), indices.last()) {
+            (Some((s, '\'')), Some((e, '\''))) |
+            (Some((s, '\"')), Some((e, '\"'))) => value[s + 1..e].to_string(),
+            _ => value.to_string(),
+        };
+        Ok(Self::new(field_id, value))
+    }
+}
+
+impl<'a> heed::BytesEncode<'a> for FacetKey {
+    type EItem = FacetKey;
+
+    fn bytes_encode(item: &'a Self::EItem) -> Option<Cow<'a, [u8]>> {
+        let mut buffer = Vec::with_capacity(2 + item.1.len());
+        let id = BEU16::new(item.key().into());
+        let id_bytes = OwnedType::bytes_encode(&id)?;
+        let value_bytes = Str::bytes_encode(item.value())?;
+        buffer.extend_from_slice(id_bytes.as_ref());
+        buffer.extend_from_slice(value_bytes.as_ref());
+        Some(Cow::Owned(buffer))
+    }
+}
+
+impl<'a> heed::BytesDecode<'a> for FacetKey {
+    type DItem = FacetKey;
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        let (id_bytes, value_bytes) = bytes.split_at(2);
+        let id = OwnedType::<BEU16>::bytes_decode(id_bytes)?;
+        let id = id.get().into();
+        let string = Str::bytes_decode(&value_bytes)?;
+        Some(FacetKey(id, string.to_string()))
+    }
+}
+
+pub fn add_to_facet_map(
+    facet_map: &mut HashMap<FacetKey, Vec<DocumentId>>,
+    field_id: FieldId,
+    value: Value,
+    document_id: DocumentId,
+) -> Result<(), FacetError> {
+    let value = match value {
+        Value::String(s) => s,
+        // ignore null
+        Value::Null => return Ok(()),
+        value => return Err(FacetError::InvalidDocumentAttribute(value.to_string())),
+    };
+    let key = FacetKey::new(field_id, value);
+    facet_map.entry(key).or_insert_with(Vec::new).push(document_id);
+    Ok(())
+}
+
+pub fn facet_map_from_docids(
+    rtxn: &heed::RoTxn<MainT>,
+    index: &crate::Index,
+    document_ids: &[DocumentId],
+    attributes_for_facetting: &[FieldId],
+) -> Result<HashMap<FacetKey, Vec<DocumentId>>, Error> {
+    let mut facet_map = HashMap::new();
+    for document_id in document_ids {
+        for result in index
+            .documents_fields
+            .document_fields(rtxn, *document_id)?
+        {
+            let (field_id, bytes) = result?;
+            if attributes_for_facetting.contains(&field_id) {
+                match serde_json::from_slice(bytes)? {
+                    Value::Array(values) => {
+                        for v in values {
+                            add_to_facet_map(&mut facet_map, field_id, v, *document_id)?;
+                        }
+                    }
+                    v => add_to_facet_map(&mut facet_map, field_id, v, *document_id)?,
+                };
+            }
+        }
+    }
+    Ok(facet_map)
+}
+
+pub fn facet_map_from_docs(
+    schema: &Schema,
+    documents: &HashMap<DocumentId, IndexMap<String, Value>>,
+    attributes_for_facetting: &[FieldId],
+) -> Result<HashMap<FacetKey, Vec<DocumentId>>, Error> {
+    let mut facet_map = HashMap::new();
+    let attributes_for_facetting = attributes_for_facetting
+        .iter()
+        .filter_map(|&id| schema.name(id).map(|name| (id, name)))
+        .collect::<Vec<_>>();
+
+    for (id, document) in documents {
+        for (field_id, name) in &attributes_for_facetting {
+            if let Some(value) = document.get(*name) {
+                match value {
+                    Value::Array(values) => {
+                        for v in values {
+                            add_to_facet_map(&mut facet_map, *field_id, v.clone(), *id)?;
+                        }
+                    }
+                    v => add_to_facet_map(&mut facet_map, *field_id, v.clone(), *id)?,
+                }
+            }
+        }
+    }
+    Ok(facet_map)
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use meilisearch_schema::Schema;
+
+    #[test]
+    fn test_facet_key() {
+        let mut schema = Schema::new();
+        let id = schema.insert_and_index("hello").unwrap();
+        let facet_list = [schema.id("hello").unwrap()];
+        assert_eq!(
+            FacetKey::from_str("hello:12", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "12".to_string())
+        );
+        assert_eq!(
+            FacetKey::from_str("hello:\"foo bar\"", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "foo bar".to_string())
+        );
+        assert_eq!(
+            FacetKey::from_str("hello:'foo bar'", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "foo bar".to_string())
+        );
+        // weird case
+        assert_eq!(
+            FacetKey::from_str("hello:blabla:machin", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "blabla:machin".to_string())
+        );
+
+        assert_eq!(
+            FacetKey::from_str("hello:\"\"", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "".to_string())
+        );
+
+        assert_eq!(
+            FacetKey::from_str("hello:'", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "'".to_string())
+        );
+        assert_eq!(
+            FacetKey::from_str("hello:''", &schema, &facet_list).unwrap(),
+            FacetKey::new(id, "".to_string())
+        );
+        assert!(FacetKey::from_str("hello", &schema, &facet_list).is_err());
+        assert!(FacetKey::from_str("toto:12", &schema, &facet_list).is_err());
+    }
+
+    #[test]
+    fn test_parse_facet_array() {
+        use either::Either::{Left, Right};
+        let mut schema = Schema::new();
+        let _id = schema.insert_and_index("hello").unwrap();
+        let facet_list = [schema.id("hello").unwrap()];
+        assert_eq!(
+            FacetFilter::from_str("[[\"hello:12\"]]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![Left(vec![FacetKey(FieldId(0), "12".to_string())])])
+        );
+        assert_eq!(
+            FacetFilter::from_str("[\"hello:12\"]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![Right(FacetKey(FieldId(0), "12".to_string()))])
+        );
+        assert_eq!(
+            FacetFilter::from_str("[\"hello:12\", \"hello:13\"]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![
+                Right(FacetKey(FieldId(0), "12".to_string())),
+                Right(FacetKey(FieldId(0), "13".to_string()))
+            ])
+        );
+        assert_eq!(
+            FacetFilter::from_str("[[\"hello:12\", \"hello:13\"]]", &schema, &facet_list).unwrap(),
+            FacetFilter(vec![Left(vec![
+                FacetKey(FieldId(0), "12".to_string()),
+                FacetKey(FieldId(0), "13".to_string())
+            ])])
+        );
+        assert_eq!(
+            FacetFilter::from_str(
+                "[[\"hello:12\", \"hello:13\"], \"hello:14\"]",
+                &schema,
+                &facet_list
+            )
+            .unwrap(),
+            FacetFilter(vec![
+                Left(vec![
+                    FacetKey(FieldId(0), "12".to_string()),
+                    FacetKey(FieldId(0), "13".to_string())
+                ]),
+                Right(FacetKey(FieldId(0), "14".to_string()))
+            ])
+        );
+
+        // invalid array depths
+        assert!(FacetFilter::from_str(
+            "[[[\"hello:12\", \"hello:13\"], \"hello:14\"]]",
+            &schema,
+            &facet_list
+        )
+        .is_err());
+        assert!(FacetFilter::from_str(
+            "[[[\"hello:12\", \"hello:13\"]], \"hello:14\"]]",
+            &schema,
+            &facet_list
+        )
+        .is_err());
+        assert!(FacetFilter::from_str("\"hello:14\"", &schema, &facet_list).is_err());
+
+        // unexisting key
+        assert!(FacetFilter::from_str("[\"foo:12\"]", &schema, &facet_list).is_err());
+
+        // invalid facet key
+        assert!(FacetFilter::from_str("[\"foo=12\"]", &schema, &facet_list).is_err());
+        assert!(FacetFilter::from_str("[\"foo12\"]", &schema, &facet_list).is_err());
+        assert!(FacetFilter::from_str("[\"\"]", &schema, &facet_list).is_err());
+
+        // empty array error
+        assert!(FacetFilter::from_str("[]", &schema, &facet_list).is_err());
+        assert!(FacetFilter::from_str("[\"hello:12\", []]", &schema, &facet_list).is_err());
+    }
+}

meilisearch-core/src/lib.rs

@@ -19,14 +19,15 @@ mod ranked_map;
 mod raw_document;
 mod reordered_attrs;
 mod update;
-pub mod settings;
 pub mod criterion;
+pub mod facets;
 pub mod raw_indexer;
+pub mod settings;
 pub mod serde;
 pub mod store;
 
 pub use self::database::{BoxUpdateFn, Database, DatabaseOptions, MainT, UpdateT};
-pub use self::error::{Error, HeedError, FstError, MResult, pest_error};
+pub use self::error::{Error, HeedError, FstError, MResult, pest_error, FacetError};
 pub use self::filters::Filter;
 pub use self::number::{Number, ParseNumberError};
 pub use self::ranked_map::RankedMap;

meilisearch-core/src/store/cow_set.rs

@@ -0,0 +1,32 @@
+use std::borrow::Cow;
+
+use heed::{types::CowSlice, BytesEncode, BytesDecode};
+use sdset::{Set, SetBuf};
+use zerocopy::{AsBytes, FromBytes};
+
+pub struct CowSet<T>(std::marker::PhantomData<T>);
+
+impl<'a, T: 'a> BytesEncode<'a> for CowSet<T>
+where
+    T: AsBytes,
+{
+    type EItem = Set<T>;
+
+    fn bytes_encode(item: &'a Self::EItem) -> Option<Cow<[u8]>> {
+        CowSlice::bytes_encode(item.as_slice())
+    }
+}
+
+impl<'a, T: 'a> BytesDecode<'a> for CowSet<T>
+where
+    T: FromBytes + Copy,
+{
+    type DItem = Cow<'a, Set<T>>;
+
+    fn bytes_decode(bytes: &'a [u8]) -> Option<Self::DItem> {
+        match CowSlice::<T>::bytes_decode(bytes)? {
+            Cow::Owned(vec) => Some(Cow::Owned(SetBuf::new_unchecked(vec))),
+            Cow::Borrowed(slice) => Some(Cow::Borrowed(Set::new_unchecked(slice))),
+        }
+    }
+}

meilisearch-core/src/store/facets.rs

@@ -0,0 +1,53 @@
+use std::borrow::Cow;
+use std::collections::HashMap;
+
+use heed::{RwTxn, RoTxn, Result as ZResult};
+use sdset::{SetBuf, Set, SetOperation};
+
+use meilisearch_types::DocumentId;
+
+use crate::database::MainT;
+use crate::facets::FacetKey;
+use super::cow_set::CowSet;
+
+/// contains facet info
+#[derive(Clone, Copy)]
+pub struct Facets {
+    pub(crate) facets: heed::Database<FacetKey, CowSet<DocumentId>>,
+}
+
+impl Facets {
+    // we use sdset::SetBuf to ensure the docids are sorted.
+    pub fn put_facet_document_ids(&self, writer: &mut RwTxn<MainT>, facet_key: FacetKey, doc_ids: &Set<DocumentId>) -> ZResult<()> {
+        self.facets.put(writer, &facet_key, doc_ids)
+    }
+
+    pub fn facet_document_ids<'txn>(&self, reader: &'txn RoTxn<MainT>, facet_key: &FacetKey) -> ZResult<Option<Cow<'txn, Set<DocumentId>>>> {
+        self.facets.get(reader, &facet_key)
+    }
+
+    /// updates the facets  store, revmoving the documents from the facets provided in the
+    /// `facet_map` argument
+    pub fn remove(&self, writer: &mut RwTxn<MainT>, facet_map: HashMap<FacetKey, Vec<DocumentId>>) -> ZResult<()> {
+        for (key, document_ids) in facet_map {
+            if let Some(old) = self.facets.get(writer, &key)? {
+                let to_remove = SetBuf::from_dirty(document_ids);
+                let new = sdset::duo::OpBuilder::new(old.as_ref(), to_remove.as_set()).difference().into_set_buf();
+                self.facets.put(writer, &key, new.as_set())?;
+            }
+        }
+        Ok(())
+    }
+
+    pub fn add(&self, writer: &mut RwTxn<MainT>, facet_map: HashMap<FacetKey, Vec<DocumentId>>) -> ZResult<()> {
+        for (key, document_ids) in facet_map {
+            let set = SetBuf::from_dirty(document_ids);
+            self.put_facet_document_ids(writer, key, set.as_set())?;
+        }
+        Ok(())
+    }
+
+    pub fn clear(self, writer: &mut heed::RwTxn<MainT>) -> ZResult<()> {
+        self.facets.clear(writer)
+    }
+}

meilisearch-core/src/store/main.rs

@@ -4,13 +4,16 @@ use std::collections::HashMap;
 use chrono::{DateTime, Utc};
 use heed::types::{ByteSlice, OwnedType, SerdeBincode, Str};
 use heed::Result as ZResult;
-use meilisearch_schema::Schema;
+use meilisearch_schema::{FieldId, Schema};
+use sdset::Set;
 
 use crate::database::MainT;
 use crate::RankedMap;
 use crate::settings::RankingRule;
+use super::cow_set::CowSet;
 
 const CREATED_AT_KEY: &str = "created-at";
+const ATTRIBUTES_FOR_FACETING: &str = "attributes-for-faceting";
 const RANKING_RULES_KEY: &str = "ranking-rules";
 const DISTINCT_ATTRIBUTE_KEY: &str = "distinct-attribute";
 const STOP_WORDS_KEY: &str = "stop-words";
@@ -188,6 +191,18 @@ impl Main {
         }
     }
 
+    pub fn attributes_for_faceting<'txn>(&self, reader: &'txn heed::RoTxn<MainT>) -> ZResult<Option<Cow<'txn, Set<FieldId>>>> {
+        self.main.get::<_, Str, CowSet<FieldId>>(reader, ATTRIBUTES_FOR_FACETING)
+    }
+
+    pub fn put_attributes_for_faceting(self, writer: &mut heed::RwTxn<MainT>, attributes: &Set<FieldId>) -> ZResult<()> {
+        self.main.put::<_, Str, CowSet<FieldId>>(writer, ATTRIBUTES_FOR_FACETING, attributes)
+    }
+
+    pub fn delete_attributes_for_faceting(self, writer: &mut heed::RwTxn<MainT>) -> ZResult<bool> {
+        self.main.delete::<_, Str>(writer, ATTRIBUTES_FOR_FACETING)
+    }
+
     pub fn ranking_rules(&self, reader: &heed::RoTxn<MainT>) -> ZResult<Option<Vec<RankingRule>>> {
         self.main.get::<_, Str, SerdeBincode<Vec<RankingRule>>>(reader, RANKING_RULES_KEY)
     }

meilisearch-core/src/store/mod.rs

@@ -1,3 +1,4 @@
+mod cow_set;
 mod docs_words;
 mod prefix_documents_cache;
 mod prefix_postings_lists_cache;
@@ -8,8 +9,10 @@ mod postings_lists;
 mod synonyms;
 mod updates;
 mod updates_results;
+mod facets;
 
 pub use self::docs_words::DocsWords;
+pub use self::facets::Facets;
 pub use self::prefix_documents_cache::PrefixDocumentsCache;
 pub use self::prefix_postings_lists_cache::PrefixPostingsListsCache;
 pub use self::documents_fields::{DocumentFieldsIter, DocumentsFields};
@@ -42,7 +45,7 @@ use crate::settings::SettingsUpdate;
 use crate::{query_builder::QueryBuilder, update, DocIndex, DocumentId, Error, MResult};
 
 type BEU64 = zerocopy::U64<byteorder::BigEndian>;
-type BEU16 = zerocopy::U16<byteorder::BigEndian>;
+pub type BEU16 = zerocopy::U16<byteorder::BigEndian>;
 
 #[derive(Debug, Copy, Clone, AsBytes, FromBytes)]
 #[repr(C)]
@@ -197,12 +200,17 @@ fn updates_results_name(name: &str) -> String {
     format!("store-{}-updates-results", name)
 }
 
+fn facets_name(name: &str) -> String {
+    format!("store-{}-facets", name)
+}
+
 #[derive(Clone)]
 pub struct Index {
     pub main: Main,
     pub postings_lists: PostingsLists,
     pub documents_fields: DocumentsFields,
     pub documents_fields_counts: DocumentsFieldsCounts,
+    pub facets: Facets,
     pub synonyms: Synonyms,
     pub docs_words: DocsWords,
     pub prefix_documents_cache: PrefixDocumentsCache,
@@ -352,29 +360,14 @@ impl Index {
     }
 
     pub fn query_builder(&self) -> QueryBuilder {
-        QueryBuilder::new(
-            self.main,
-            self.postings_lists,
-            self.documents_fields_counts,
-            self.synonyms,
-            self.prefix_documents_cache,
-            self.prefix_postings_lists_cache,
-        )
+        QueryBuilder::new(self)
     }
 
-    pub fn query_builder_with_criteria<'c, 'f, 'd>(
-        &self,
+    pub fn query_builder_with_criteria<'c, 'f, 'd, 'fa, 'i>(
+        &'i self,
         criteria: Criteria<'c>,
-    ) -> QueryBuilder<'c, 'f, 'd> {
-        QueryBuilder::with_criteria(
-            self.main,
-            self.postings_lists,
-            self.documents_fields_counts,
-            self.synonyms,
-            self.prefix_documents_cache,
-            self.prefix_postings_lists_cache,
-            criteria,
-        )
+    ) -> QueryBuilder<'c, 'f, 'd, 'fa, 'i> {
+        QueryBuilder::with_criteria(self, criteria)
     }
 }
 
@@ -395,12 +388,14 @@ pub fn create(
     let prefix_postings_lists_cache_name = prefix_postings_lists_cache_name(name);
     let updates_name = updates_name(name);
     let updates_results_name = updates_results_name(name);
+    let facets_name = facets_name(name);
 
     // open all the stores
     let main = env.create_poly_database(Some(&main_name))?;
     let postings_lists = env.create_database(Some(&postings_lists_name))?;
     let documents_fields = env.create_database(Some(&documents_fields_name))?;
     let documents_fields_counts = env.create_database(Some(&documents_fields_counts_name))?;
+    let facets = env.create_database(Some(&facets_name))?;
     let synonyms = env.create_database(Some(&synonyms_name))?;
     let docs_words = env.create_database(Some(&docs_words_name))?;
     let prefix_documents_cache = env.create_database(Some(&prefix_documents_cache_name))?;
@@ -417,6 +412,8 @@ pub fn create(
         docs_words: DocsWords { docs_words },
         prefix_postings_lists_cache: PrefixPostingsListsCache { prefix_postings_lists_cache },
         prefix_documents_cache: PrefixDocumentsCache { prefix_documents_cache },
+        facets: Facets { facets },
+
         updates: Updates { updates },
         updates_results: UpdatesResults { updates_results },
         updates_notifier,
@@ -437,6 +434,7 @@ pub fn open(
     let synonyms_name = synonyms_name(name);
     let docs_words_name = docs_words_name(name);
     let prefix_documents_cache_name = prefix_documents_cache_name(name);
+    let facets_name = facets_name(name);
     let prefix_postings_lists_cache_name = prefix_postings_lists_cache_name(name);
     let updates_name = updates_name(name);
     let updates_results_name = updates_results_name(name);
@@ -470,6 +468,10 @@ pub fn open(
         Some(prefix_documents_cache) => prefix_documents_cache,
         None => return Ok(None),
     };
+    let facets = match env.open_database(Some(&facets_name))? {
+        Some(facets) => facets,
+        None => return Ok(None),
+    };
     let prefix_postings_lists_cache = match env.open_database(Some(&prefix_postings_lists_cache_name))? {
         Some(prefix_postings_lists_cache) => prefix_postings_lists_cache,
         None => return Ok(None),
@@ -491,6 +493,7 @@ pub fn open(
         synonyms: Synonyms { synonyms },
         docs_words: DocsWords { docs_words },
         prefix_documents_cache: PrefixDocumentsCache { prefix_documents_cache },
+        facets: Facets { facets },
         prefix_postings_lists_cache: PrefixPostingsListsCache { prefix_postings_lists_cache },
         updates: Updates { updates },
         updates_results: UpdatesResults { updates_results },