Introduce index soft deletion

meilidb-core/src/database.rs

@@ -4,7 +4,7 @@ use std::path::Path;
 use std::sync::{Arc, RwLock};
 use std::{fs, thread};
 
-use crossbeam_channel::Receiver;
+use crossbeam_channel::{Receiver, Sender};
 use heed::types::{Str, Unit};
 use heed::{CompactionOption, Result as ZResult};
 use log::debug;
@@ -33,9 +33,17 @@ macro_rules! r#break_try {
     };
 }
 
-fn update_awaiter(receiver: Receiver<()>, env: heed::Env, update_fn: Arc<ArcSwapFn>, index: Index) {
-    for () in receiver {
-        // consume all updates in order (oldest first)
+pub enum UpdateEvent {
+    NewUpdate,
+    MustStop,
+}
+
+pub type UpdateEvents = Receiver<UpdateEvent>;
+pub type UpdateEventsEmitter = Sender<UpdateEvent>;
+
+fn update_awaiter(receiver: UpdateEvents, env: heed::Env, update_fn: Arc<ArcSwapFn>, index: Index) {
+    let mut receiver = receiver.into_iter();
+    while let Some(UpdateEvent::NewUpdate) = receiver.next() {
         loop {
             // instantiate a main/parent transaction
             let mut writer = break_try!(env.write_txn(), "LMDB write transaction begin failed");
@@ -80,6 +88,8 @@ fn update_awaiter(receiver: Receiver<()>, env: heed::Env, update_fn: Arc<ArcSwap
             }
         }
     }
+
+    debug!("update loop system stopped");
 }
 
 impl Database {
@@ -130,7 +140,7 @@ impl Database {
 
             // send an update notification to make sure that
             // possible pre-boot updates are consumed
-            sender.send(()).unwrap();
+            sender.send(UpdateEvent::NewUpdate).unwrap();
 
             let result = indexes.insert(index_name, (index, update_fn, handle));
             assert!(
@@ -186,6 +196,28 @@ impl Database {
         }
     }
 
+    pub fn delete_index(&self, name: impl AsRef<str>) -> MResult<bool> {
+        let name = name.as_ref();
+        let mut indexes_lock = self.indexes.write().unwrap();
+
+        match indexes_lock.remove_entry(name) {
+            Some((name, (index, _fn, handle))) => {
+                // remove the index name from the list of indexes
+                // and clear all the LMDB dbi
+                let mut writer = self.env.write_txn()?;
+                self.indexes_store.delete(&mut writer, &name)?;
+                store::clear(&mut writer, &index)?;
+                writer.commit()?;
+
+                // join the update loop thread to ensure it is stopped
+                handle.join().unwrap();
+
+                Ok(true)
+            }
+            None => Ok(false),
+        }
+    }
+
     pub fn set_update_callback(&self, name: impl AsRef<str>, update_fn: BoxUpdateFn) -> bool {
         let indexes_lock = self.indexes.read().unwrap();
         match indexes_lock.get(name.as_ref()) {

meilidb-core/src/store/main.rs

@@ -18,6 +18,10 @@ pub struct Main {
 }
 
 impl Main {
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.main.clear(writer)
+    }
+
     pub fn put_words_fst(self, writer: &mut heed::RwTxn, fst: &fst::Set) -> ZResult<()> {
         let bytes = fst.as_fst().as_bytes();
         self.main.put::<Str, ByteSlice>(writer, WORDS_KEY, bytes)

meilidb-core/src/store/mod.rs

@@ -26,6 +26,7 @@ use serde::de::{self, Deserialize};
 use zerocopy::{AsBytes, FromBytes};
 
 use crate::criterion::Criteria;
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::serde::Deserializer;
 use crate::{query_builder::QueryBuilder, update, DocumentId, Error, MResult};
 
@@ -91,7 +92,7 @@ pub struct Index {
 
     pub updates: Updates,
     pub updates_results: UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
 }
 
 impl Index {
@@ -139,12 +140,12 @@ impl Index {
     }
 
     pub fn schema_update(&self, writer: &mut heed::RwTxn, schema: Schema) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         update::push_schema_update(writer, self.updates, self.updates_results, schema)
     }
 
     pub fn customs_update(&self, writer: &mut heed::RwTxn, customs: Vec<u8>) -> ZResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         update::push_customs_update(writer, self.updates, self.updates_results, customs)
     }
 
@@ -173,7 +174,7 @@ impl Index {
     }
 
     pub fn clear_all(&self, writer: &mut heed::RwTxn) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         update::push_clear_all(writer, self.updates, self.updates_results)
     }
 
@@ -276,7 +277,7 @@ impl Index {
 pub fn create(
     env: &heed::Env,
     name: &str,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
 ) -> MResult<Index> {
     // create all the store names
     let main_name = main_name(name);
@@ -316,7 +317,7 @@ pub fn create(
 pub fn open(
     env: &heed::Env,
     name: &str,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
 ) -> MResult<Option<Index>> {
     // create all the store names
     let main_name = main_name(name);
@@ -376,3 +377,19 @@ pub fn open(
         updates_notifier,
     }))
 }
+
+pub fn clear(writer: &mut heed::RwTxn, index: &Index) -> MResult<()> {
+    // send a stop event to the update loop of the index
+    index.updates_notifier.send(UpdateEvent::MustStop).unwrap();
+
+    // clear all the stores
+    index.main.clear(writer)?;
+    index.postings_lists.clear(writer)?;
+    index.documents_fields.clear(writer)?;
+    index.documents_fields_counts.clear(writer)?;
+    index.synonyms.clear(writer)?;
+    index.docs_words.clear(writer)?;
+    index.updates.clear(writer)?;
+    index.updates_results.clear(writer)?;
+    Ok(())
+}

meilidb-core/src/store/synonyms.rs

@@ -22,6 +22,10 @@ impl Synonyms {
         self.synonyms.delete(writer, word)
     }
 
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.synonyms.clear(writer)
+    }
+
     pub fn synonyms(self, reader: &heed::RoTxn, word: &[u8]) -> ZResult<Option<fst::Set>> {
         match self.synonyms.get(reader, word)? {
             Some(bytes) => {

meilidb-core/src/store/updates.rs

@@ -52,4 +52,8 @@ impl Updates {
             None => Ok(None),
         }
     }
+
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.updates.clear(writer)
+    }
 }

meilidb-core/src/store/updates_results.rs

@@ -38,4 +38,8 @@ impl UpdatesResults {
         let update_id = BEU64::new(update_id);
         self.updates_results.get(reader, &update_id)
     }
+
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.updates_results.clear(writer)
+    }
 }

meilidb-core/src/update/documents_addition.rs

@@ -4,6 +4,7 @@ use fst::{set::OpBuilder, SetBuilder};
 use sdset::{duo::Union, SetOperation};
 use serde::{Deserialize, Serialize};
 
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::raw_indexer::RawIndexer;
 use crate::serde::{extract_document_id, serialize_value, Deserializer, Serializer};
 use crate::store;
@@ -13,7 +14,7 @@ use crate::{Error, MResult, RankedMap};
 pub struct DocumentsAddition<D> {
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
     documents: Vec<D>,
     is_partial: bool,
 }
@@ -22,7 +23,7 @@ impl<D> DocumentsAddition<D> {
     pub fn new(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> DocumentsAddition<D> {
         DocumentsAddition {
             updates_store,
@@ -36,7 +37,7 @@ impl<D> DocumentsAddition<D> {
     pub fn new_partial(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> DocumentsAddition<D> {
         DocumentsAddition {
             updates_store,
@@ -55,7 +56,7 @@ impl<D> DocumentsAddition<D> {
     where
         D: serde::Serialize,
     {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         let update_id = push_documents_addition(
             writer,
             self.updates_store,

meilidb-core/src/update/documents_deletion.rs

@@ -4,6 +4,7 @@ use fst::{SetBuilder, Streamer};
 use meilidb_schema::Schema;
 use sdset::{duo::DifferenceByKey, SetBuf, SetOperation};
 
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::serde::extract_document_id;
 use crate::store;
 use crate::update::{next_update_id, Update};
@@ -12,7 +13,7 @@ use crate::{DocumentId, Error, MResult, RankedMap};
 pub struct DocumentsDeletion {
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
     documents: Vec<DocumentId>,
 }
 
@@ -20,7 +21,7 @@ impl DocumentsDeletion {
     pub fn new(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> DocumentsDeletion {
         DocumentsDeletion {
             updates_store,
@@ -50,7 +51,7 @@ impl DocumentsDeletion {
     }
 
     pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         let update_id = push_documents_deletion(
             writer,
             self.updates_store,

meilidb-core/src/update/stop_words_addition.rs

@@ -3,13 +3,14 @@ use std::collections::BTreeSet;
 use fst::{set::OpBuilder, SetBuilder};
 
 use crate::automaton::normalize_str;
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::update::{next_update_id, Update};
 use crate::{store, MResult};
 
 pub struct StopWordsAddition {
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
     stop_words: BTreeSet<String>,
 }
 
@@ -17,7 +18,7 @@ impl StopWordsAddition {
     pub fn new(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> StopWordsAddition {
         StopWordsAddition {
             updates_store,
@@ -33,7 +34,7 @@ impl StopWordsAddition {
     }
 
     pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         let update_id = push_stop_words_addition(
             writer,
             self.updates_store,

meilidb-core/src/update/stop_words_deletion.rs

@@ -3,6 +3,7 @@ use std::collections::BTreeSet;
 use fst::{set::OpBuilder, SetBuilder};
 
 use crate::automaton::normalize_str;
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::update::documents_addition::reindex_all_documents;
 use crate::update::{next_update_id, Update};
 use crate::{store, MResult};
@@ -10,7 +11,7 @@ use crate::{store, MResult};
 pub struct StopWordsDeletion {
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
     stop_words: BTreeSet<String>,
 }
 
@@ -18,7 +19,7 @@ impl StopWordsDeletion {
     pub fn new(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> StopWordsDeletion {
         StopWordsDeletion {
             updates_store,
@@ -34,7 +35,7 @@ impl StopWordsDeletion {
     }
 
     pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         let update_id = push_stop_words_deletion(
             writer,
             self.updates_store,

meilidb-core/src/update/synonyms_addition.rs

@@ -4,13 +4,14 @@ use fst::{set::OpBuilder, SetBuilder};
 use sdset::SetBuf;
 
 use crate::automaton::normalize_str;
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::update::{next_update_id, Update};
 use crate::{store, MResult};
 
 pub struct SynonymsAddition {
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
     synonyms: BTreeMap<String, Vec<String>>,
 }
 
@@ -18,7 +19,7 @@ impl SynonymsAddition {
     pub fn new(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> SynonymsAddition {
         SynonymsAddition {
             updates_store,
@@ -43,7 +44,7 @@ impl SynonymsAddition {
     }
 
     pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         let update_id = push_synonyms_addition(
             writer,
             self.updates_store,

meilidb-core/src/update/synonyms_deletion.rs

@@ -5,13 +5,14 @@ use fst::{set::OpBuilder, SetBuilder};
 use sdset::SetBuf;
 
 use crate::automaton::normalize_str;
+use crate::database::{UpdateEvent, UpdateEventsEmitter};
 use crate::update::{next_update_id, Update};
 use crate::{store, MResult};
 
 pub struct SynonymsDeletion {
     updates_store: store::Updates,
     updates_results_store: store::UpdatesResults,
-    updates_notifier: crossbeam_channel::Sender<()>,
+    updates_notifier: UpdateEventsEmitter,
     synonyms: BTreeMap<String, Option<Vec<String>>>,
 }
 
@@ -19,7 +20,7 @@ impl SynonymsDeletion {
     pub fn new(
         updates_store: store::Updates,
         updates_results_store: store::UpdatesResults,
-        updates_notifier: crossbeam_channel::Sender<()>,
+        updates_notifier: UpdateEventsEmitter,
     ) -> SynonymsDeletion {
         SynonymsDeletion {
             updates_store,
@@ -50,7 +51,7 @@ impl SynonymsDeletion {
     }
 
     pub fn finalize(self, writer: &mut heed::RwTxn) -> MResult<u64> {
-        let _ = self.updates_notifier.send(());
+        let _ = self.updates_notifier.send(UpdateEvent::NewUpdate);
         let update_id = push_synonyms_deletion(
             writer,
             self.updates_store,