Introduce a clear all documents update

meilidb-core/src/store/docs_words.rs

@@ -26,6 +26,10 @@ impl DocsWords {
         self.docs_words.delete(writer, &document_id)
     }
 
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.docs_words.clear(writer)
+    }
+
     pub fn doc_words(
         self,
         reader: &heed::RoTxn,

meilidb-core/src/store/documents_fields.rs

@@ -32,6 +32,10 @@ impl DocumentsFields {
         self.documents_fields.delete_range(writer, start..=end)
     }
 
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.documents_fields.clear(writer)
+    }
+
     pub fn document_attribute<'txn>(
         self,
         reader: &'txn heed::RoTxn,

meilidb-core/src/store/documents_fields_counts.rs

@@ -32,6 +32,10 @@ impl DocumentsFieldsCounts {
             .delete_range(writer, start..=end)
     }
 
+    pub fn clear(self, writer: &mut heed::RwTxn) -> ZResult<()> {
+        self.documents_fields_counts.clear(writer)
+    }
+
     pub fn document_field_count(
         self,
         reader: &heed::RoTxn,

meilidb-core/src/store/mod.rs

@@ -166,6 +166,10 @@ impl Index {
         )
     }
 
+    pub fn clear_all(&self, writer: &mut heed::RwTxn) -> MResult<u64> {
+        update::push_clear_all(writer, self.updates, self.updates_results)
+    }
+
     pub fn synonyms_addition(&self) -> update::SynonymsAddition {
         update::SynonymsAddition::new(
             self.updates,

meilidb-core/src/update/clear_all.rs

@@ -0,0 +1,36 @@
+use meilidb_schema::{Diff, Schema};
+
+use crate::update::documents_addition::reindex_all_documents;
+use crate::update::{next_update_id, Update};
+use crate::{error::UnsupportedOperation, store, MResult, RankedMap};
+
+pub fn apply_clear_all(
+    writer: &mut heed::RwTxn,
+    main_store: store::Main,
+    documents_fields_store: store::DocumentsFields,
+    documents_fields_counts_store: store::DocumentsFieldsCounts,
+    postings_lists_store: store::PostingsLists,
+    docs_words_store: store::DocsWords,
+) -> MResult<()> {
+    main_store.put_words_fst(writer, &fst::Set::default())?;
+    main_store.put_ranked_map(writer, &RankedMap::default())?;
+    main_store.put_number_of_documents(writer, |_| 0)?;
+    documents_fields_store.clear(writer)?;
+    documents_fields_counts_store.clear(writer)?;
+    postings_lists_store.clear(writer)?;
+    docs_words_store.clear(writer)?;
+
+    Ok(())
+}
+
+pub fn push_clear_all(
+    writer: &mut heed::RwTxn,
+    updates_store: store::Updates,
+    updates_results_store: store::UpdatesResults,
+) -> MResult<u64> {
+    let last_update_id = next_update_id(writer, updates_store, updates_results_store)?;
+    let update = Update::ClearAll;
+    updates_store.put_update(writer, last_update_id, &update)?;
+
+    Ok(last_update_id)
+}

meilidb-core/src/update/documents_addition.rs

@@ -184,6 +184,7 @@ pub fn reindex_all_documents(
     main_store.put_ranked_map(writer, &ranked_map)?;
     main_store.put_number_of_documents(writer, |_| 0)?;
     postings_lists_store.clear(writer)?;
+    docs_words_store.clear(writer)?;
 
     // 3. re-index one document by one document (otherwise we make the borrow checker unhappy)
     let mut indexer = RawIndexer::new();

meilidb-core/src/update/mod.rs

@@ -1,3 +1,4 @@
+mod clear_all;
 mod customs_update;
 mod documents_addition;
 mod documents_deletion;
@@ -5,6 +6,7 @@ mod schema_update;
 mod synonyms_addition;
 mod synonyms_deletion;
 
+pub use self::clear_all::{apply_clear_all, push_clear_all};
 pub use self::customs_update::{apply_customs_update, push_customs_update};
 pub use self::documents_addition::{apply_documents_addition, DocumentsAddition};
 pub use self::documents_deletion::{apply_documents_deletion, DocumentsDeletion};
@@ -25,6 +27,7 @@ use meilidb_schema::Schema;
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum Update {
+    ClearAll,
     Schema(Schema),
     Customs(Vec<u8>),
     DocumentsAddition(Vec<serde_json::Value>),
@@ -35,6 +38,7 @@ pub enum Update {
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum UpdateType {
+    ClearAll,
     Schema { schema: Schema },
     Customs,
     DocumentsAddition { number: usize },
@@ -107,6 +111,21 @@ pub fn update_task(writer: &mut heed::RwTxn, index: store::Index) -> MResult<Opt
     debug!("Processing update number {}", update_id);
 
     let (update_type, result, duration) = match update {
+        Update::ClearAll => {
+            let start = Instant::now();
+
+            let update_type = UpdateType::ClearAll;
+            let result = apply_clear_all(
+                writer,
+                index.main,
+                index.documents_fields,
+                index.documents_fields_counts,
+                index.postings_lists,
+                index.docs_words,
+            );
+
+            (update_type, result, start.elapsed())
+        }
         Update::Schema(schema) => {
             let start = Instant::now();