feat: Allow users to manage multiple database indexes

Cargo.toml

@@ -22,6 +22,7 @@ serde_json = { version = "1.0", features = ["preserve_order"] }
 slice-group-by = "0.2"
 unidecode = "0.3"
 rayon = "1.0"
+lockfree = "0.5.1"
 
 [dependencies.toml]
 git = "https://github.com/Kerollmops/toml-rs.git"

examples/create-database.rs

@@ -50,7 +50,9 @@ fn index(
     stop_words: &HashSet<String>,
 ) -> Result<Database, Box<Error>>
 {
-    let database = Database::create(database_path, &schema)?;
+    let database = Database::create(database_path)?;
+
+    database.create_index("default", &schema)?;
 
     let mut rdr = csv::Reader::from_path(csv_data_path)?;
     let mut raw_record = csv::StringRecord::new();
@@ -61,7 +63,7 @@ fn index(
 
     while !end_of_file {
         let tokenizer_builder = DefaultBuilder::new();
-        let mut update = database.start_update()?;
+        let mut update = database.start_update("default")?;
 
         loop {
             end_of_file = !rdr.read_record(&mut raw_record)?;

examples/query-database.rs

@@ -116,7 +116,7 @@ fn main() -> Result<(), Box<Error>> {
         if input.read_line(&mut buffer)? == 0 { break }
         let query = buffer.trim_end_matches('\n');
 
-        let view = database.view();
+        let view = database.view("default")?;
         let schema = view.schema();
 
         let (elapsed, documents) = elapsed::measure_time(|| {

src/database/mod.rs

@@ -1,13 +1,17 @@
-use std::error::Error;
-use std::path::Path;
-use std::ops::Deref;
 use std::sync::Arc;
+use std::error::Error;
+use std::ffi::OsStr;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::sync::atomic::{AtomicBool, Ordering};
+use std::ops::{Deref, DerefMut};
 
-use rocksdb::rocksdb_options::{DBOptions, ColumnFamilyOptions};
-use rocksdb::rocksdb::{Writable, Snapshot};
-use rocksdb::{DB, MergeOperands};
 use crossbeam::atomic::ArcCell;
-use log::info;
+use log::{info, error, warn};
+use rocksdb::rocksdb::{Writable, Snapshot};
+use rocksdb::rocksdb_options::{DBOptions, ColumnFamilyOptions};
+use rocksdb::{DB, MergeOperands};
+use lockfree::map::Map;
 
 pub use self::document_key::{DocumentKey, DocumentKeyAttr};
 pub use self::view::{DatabaseView, DocumentIter};
@@ -77,21 +81,48 @@ fn merge_indexes(key: &[u8], existing: Option<&[u8]>, operands: &mut MergeOperan
     bytes
 }
 
-pub struct Database {
+pub struct IndexUpdate {
-    db: Arc<DB>,
+    index: String,
-    // This view is updated each time the DB ingests an update
+    update: Update,
-    view: ArcCell<DatabaseView<Arc<DB>>>,
 }
 
-impl Database {
+impl Deref for IndexUpdate {
-    pub fn create<P: AsRef<Path>>(path: P, schema: &Schema) -> Result<Database, Box<Error>> {
+    type Target = Update;
+
+    fn deref(&self) -> &Update {
+        &self.update
+    }
+}
+
+impl DerefMut for IndexUpdate {
+    fn deref_mut(&mut self) -> &mut Update {
+        &mut self.update
+    }
+}
+
+struct DatabaseIndex {
+    db: Arc<DB>,
+
+    // This view is updated each time the DB ingests an update
+    view: ArcCell<DatabaseView<Arc<DB>>>,
+
+    // This path is the path to the mdb folder stored on disk
+    path: PathBuf,
+
+    // must_die false by default, must be set as true when the Index is dropped.
+    // It's used to erase the folder saved on disk when the user request to delete an index
+    must_die: AtomicBool,
+}
+
+impl DatabaseIndex {
+    fn create<P: AsRef<Path>>(path: P, schema: &Schema) -> Result<DatabaseIndex, Box<Error>> {
         let path = path.as_ref();
         if path.exists() {
             return Err(format!("File already exists at path: {}, cannot create database.",
                                 path.display()).into())
         }
 
-        let path = path.to_string_lossy();
+        let path_lossy = path.to_string_lossy();
         let mut opts = DBOptions::new();
         opts.create_if_missing(true);
         // opts.error_if_exists(true); // FIXME pull request that
@@ -99,7 +130,7 @@ impl Database {
         let mut cf_opts = ColumnFamilyOptions::new();
         cf_opts.add_merge_operator("data-index merge operator", merge_indexes);
 
-        let db = DB::open_cf(opts, &path, vec![("default", cf_opts)])?;
+        let db = DB::open_cf(opts, &path_lossy, vec![("default", cf_opts)])?;
 
         let mut schema_bytes = Vec::new();
         schema.write_to_bin(&mut schema_bytes)?;
@@ -109,11 +140,17 @@ impl Database {
         let snapshot = Snapshot::new(db.clone());
         let view = ArcCell::new(Arc::new(DatabaseView::new(snapshot)?));
 
-        Ok(Database { db, view })
+
+        Ok(DatabaseIndex {
+            db: db,
+            view: view,
+            path: path.to_path_buf(),
+            must_die: AtomicBool::new(false)
+        })
     }
 
-    pub fn open<P: AsRef<Path>>(path: P) -> Result<Database, Box<Error>> {
+    fn open<P: AsRef<Path>>(path: P) -> Result<DatabaseIndex, Box<Error>> {
-        let path = path.as_ref().to_string_lossy();
+        let path_lossy = path.as_ref().to_string_lossy();
 
         let mut opts = DBOptions::new();
         opts.create_if_missing(false);
@@ -121,7 +158,7 @@ impl Database {
         let mut cf_opts = ColumnFamilyOptions::new();
         cf_opts.add_merge_operator("data-index merge operator", merge_indexes);
 
-        let db = DB::open_cf(opts, &path, vec![("default", cf_opts)])?;
+        let db = DB::open_cf(opts, &path_lossy, vec![("default", cf_opts)])?;
 
         // FIXME create a generic function to do that !
         let _schema = match db.get(DATA_SCHEMA)? {
@@ -133,10 +170,19 @@ impl Database {
         let snapshot = Snapshot::new(db.clone());
         let view = ArcCell::new(Arc::new(DatabaseView::new(snapshot)?));
 
-        Ok(Database { db, view })
+        Ok(DatabaseIndex {
+            db: db,
+            view: view,
+            path: path.as_ref().to_path_buf(),
+            must_die: AtomicBool::new(false)
+        })
     }
 
-    pub fn start_update(&self) -> Result<Update, Box<Error>> {
+    fn must_die(&self) {
+        self.must_die.store(true, Ordering::Relaxed)
+    }
+
+    fn start_update(&self) -> Result<Update, Box<Error>> {
         let schema = match self.db.get(DATA_SCHEMA)? {
             Some(value) => Schema::read_from_bin(&*value)?,
             None => panic!("Database does not contain a schema"),
@@ -145,7 +191,7 @@ impl Database {
         Ok(Update::new(schema))
     }
 
-    pub fn commit_update(&self, update: Update) -> Result<Arc<DatabaseView<Arc<DB>>>, Box<Error>> {
+    fn commit_update(&self, update: Update) -> Result<Arc<DatabaseView<Arc<DB>>>, Box<Error>> {
         let batch = update.build()?;
         self.db.write(batch)?;
 
@@ -156,11 +202,115 @@ impl Database {
         Ok(view)
     }
 
-    pub fn view(&self) -> Arc<DatabaseView<Arc<DB>>> {
+    fn view(&self) -> Arc<DatabaseView<Arc<DB>>> {
         self.view.get()
     }
 }
 
+impl Drop for DatabaseIndex {
+    fn drop(&mut self) {
+        if self.must_die.load(Ordering::Relaxed) {
+            if let Err(err) = fs::remove_dir_all(&self.path) {
+                error!("Impossible to remove mdb when Database id dropped; {}", err);
+            }
+        }
+    }
+}
+
+pub struct Database {
+    indexes: Map<String, Arc<DatabaseIndex>>,
+    path: PathBuf,
+}
+
+impl Database {
+    pub fn create<P: AsRef<Path>>(path: P) -> Result<Database, Box<Error>> {
+        Ok(Database {
+            indexes: Map::new(),
+            path: path.as_ref().to_path_buf(),
+        })
+    }
+
+    pub fn open<P: AsRef<Path>>(path: P) -> Result<Database, Box<Error>> {
+        let entries = fs::read_dir(&path)?;
+
+        let indexes = Map::new();
+        for entry in entries {
+            let path = match entry {
+                Ok(p) => p.path(),
+                Err(err) => {
+                    warn!("Impossible to retrieve the path from an entry; {}", err);
+                    continue
+                }
+            };
+
+            let name = match path.file_stem().and_then(OsStr::to_str) {
+                Some(name) => name.to_owned(),
+                None => continue
+            };
+
+            let db = match DatabaseIndex::open(path.clone()) {
+                Ok(db) => db,
+                Err(err) => {
+                    warn!("Impossible to open the database; {}", err);
+                    continue
+                }
+            };
+
+            info!("Load database {}", name);
+            indexes.insert(name, Arc::new(db));
+        }
+
+        Ok(Database {
+            indexes: indexes,
+            path: path.as_ref().to_path_buf(),
+        })
+    }
+
+    pub fn create_index(&self, name: &str, schema: &Schema) -> Result<(), Box<Error>> {
+        let index_path = self.path.join(name);
+
+        if index_path.exists() {
+            return Err("Index already exists".into());
+        }
+
+        let index = DatabaseIndex::create(index_path, schema)?;
+        self.indexes.insert(name.to_owned(), Arc::new(index));
+
+        Ok(())
+    }
+
+    pub fn delete_index(&self, name: &str) -> Result<(), Box<Error>> {
+        let index_guard = self.indexes.remove(name).ok_or("Index not found")?;
+        index_guard.val().must_die();
+
+        Ok(())
+    }
+
+    pub fn list_indexes(&self) -> Vec<String> {
+        self.indexes.iter().map(|g| g.key().clone()).collect()
+    }
+
+    pub fn start_update(&self, index: &str) -> Result<IndexUpdate, Box<Error>> {
+        let index_guard = self.indexes.get(index).ok_or("Index not found")?;
+        let update = index_guard.val().start_update()?;
+
+        Ok(IndexUpdate { index: index.to_owned(), update })
+    }
+
+    pub fn commit_update(&self, update: IndexUpdate)-> Result<Arc<DatabaseView<Arc<DB>>>, Box<Error>> {
+        let index_guard = self.indexes.get(&update.index).ok_or("Index not found")?;
+
+        index_guard.val().commit_update(update.update)
+    }
+
+    pub fn view(&self, index: &str) -> Result<Arc<DatabaseView<Arc<DB>>>, Box<Error>> {
+        let index_guard = self.indexes.get(index).ok_or("Index not found")?;
+
+        Ok(index_guard.val().view())
+    }
+
+}
+
 #[cfg(test)]
 mod tests {
     use std::collections::HashSet;
@@ -179,6 +329,7 @@ mod tests {
         let stop_words = HashSet::new();
 
         let meilidb_path = dir.path().join("meilidb.mdb");
+        let meilidb_index_name = "default";
 
         #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
         struct SimpleDoc {
@@ -197,7 +348,9 @@ mod tests {
             builder.build()
         };
 
-        let database = Database::create(&meilidb_path, &schema)?;
+        let database = Database::create(&meilidb_path)?;
+
+        database.create_index(meilidb_index_name, &schema)?;
 
         let doc0 = SimpleDoc {
             id: 0,
@@ -213,7 +366,7 @@ mod tests {
         };
 
         let tokenizer_builder = DefaultBuilder::new();
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(meilidb_index_name)?;
 
         let docid0 = builder.update_document(&doc0, &tokenizer_builder, &stop_words)?;
         let docid1 = builder.update_document(&doc1, &tokenizer_builder, &stop_words)?;
@@ -235,6 +388,7 @@ mod tests {
         let stop_words = HashSet::new();
 
         let meilidb_path = dir.path().join("meilidb.mdb");
+        let meilidb_index_name = "default";
 
         #[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
         struct SimpleDoc {
@@ -253,7 +407,9 @@ mod tests {
             builder.build()
         };
 
-        let database = Database::create(&meilidb_path, &schema)?;
+        let database = Database::create(&meilidb_path)?;
+
+        database.create_index(meilidb_index_name, &schema)?;
 
         let doc0 = SimpleDoc {
             id: 0,
@@ -282,12 +438,12 @@ mod tests {
 
         let tokenizer_builder = DefaultBuilder::new();
 
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(meilidb_index_name)?;
         let docid0 = builder.update_document(&doc0, &tokenizer_builder, &stop_words)?;
         let docid1 = builder.update_document(&doc1, &tokenizer_builder, &stop_words)?;
         database.commit_update(builder)?;
 
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(meilidb_index_name)?;
         let docid2 = builder.update_document(&doc2, &tokenizer_builder, &stop_words)?;
         let docid3 = builder.update_document(&doc3, &tokenizer_builder, &stop_words)?;
         let view = database.commit_update(builder)?;
@@ -359,7 +515,10 @@ mod bench {
         let schema = builder.build();
 
         let db_path = dir.path().join("bench.mdb");
-        let database = Database::create(db_path.clone(), &schema)?;
+        let index_name = "default";
+
+        let database = Database::create(&db_path)?;
+        database.create_index(index_name, &schema)?;
 
         #[derive(Serialize)]
         struct Document {
@@ -369,7 +528,7 @@ mod bench {
         }
 
         let tokenizer_builder = DefaultBuilder;
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(index_name)?;
         let mut rng = XorShiftRng::seed_from_u64(42);
 
         for i in 0..300 {
@@ -404,7 +563,10 @@ mod bench {
         let schema = builder.build();
 
         let db_path = dir.path().join("bench.mdb");
-        let database = Database::create(db_path.clone(), &schema)?;
+        let index_name = "default";
+
+        let database = Database::create(&db_path)?;
+        database.create_index(index_name, &schema)?;
 
         #[derive(Serialize)]
         struct Document {
@@ -414,7 +576,7 @@ mod bench {
         }
 
         let tokenizer_builder = DefaultBuilder;
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(index_name)?;
         let mut rng = XorShiftRng::seed_from_u64(42);
 
         for i in 0..3000 {
@@ -450,7 +612,10 @@ mod bench {
         let schema = builder.build();
 
         let db_path = dir.path().join("bench.mdb");
-        let database = Database::create(db_path.clone(), &schema)?;
+        let index_name = "default";
+
+        let database = Database::create(&db_path)?;
+        database.create_index(index_name, &schema)?;
 
         #[derive(Serialize)]
         struct Document {
@@ -460,7 +625,7 @@ mod bench {
         }
 
         let tokenizer_builder = DefaultBuilder;
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(index_name)?;
         let mut rng = XorShiftRng::seed_from_u64(42);
 
         for i in 0..30_000 {
@@ -495,7 +660,10 @@ mod bench {
         let schema = builder.build();
 
         let db_path = dir.path().join("bench.mdb");
-        let database = Database::create(db_path.clone(), &schema)?;
+        let index_name = "default";
+
+        let database = Database::create(&db_path)?;
+        database.create_index(index_name, &schema)?;
 
         #[derive(Serialize)]
         struct Document {
@@ -505,7 +673,7 @@ mod bench {
         }
 
         let tokenizer_builder = DefaultBuilder;
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(index_name)?;
         let mut rng = XorShiftRng::seed_from_u64(42);
 
         for i in 0..300 {
@@ -540,7 +708,10 @@ mod bench {
         let schema = builder.build();
 
         let db_path = dir.path().join("bench.mdb");
-        let database = Database::create(db_path.clone(), &schema)?;
+        let index_name = "default";
+
+        let database = Database::create(&db_path)?;
+        database.create_index(index_name, &schema)?;
 
         #[derive(Serialize)]
         struct Document {
@@ -550,7 +721,7 @@ mod bench {
         }
 
         let tokenizer_builder = DefaultBuilder;
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(index_name)?;
         let mut rng = XorShiftRng::seed_from_u64(42);
 
         for i in 0..3000 {
@@ -586,7 +757,10 @@ mod bench {
         let schema = builder.build();
 
         let db_path = dir.path().join("bench.mdb");
-        let database = Database::create(db_path.clone(), &schema)?;
+        let index_name = "default";
+
+        let database = Database::create(&db_path)?;
+        database.create_index(index_name, &schema)?;
 
         #[derive(Serialize)]
         struct Document {
@@ -596,7 +770,7 @@ mod bench {
         }
 
         let tokenizer_builder = DefaultBuilder;
-        let mut builder = database.start_update()?;
+        let mut builder = database.start_update(index_name)?;
         let mut rng = XorShiftRng::seed_from_u64(42);
 
         for i in 0..30_000 {