refactor: tables

src/catalog/src/information_schema.rs

@@ -69,18 +69,19 @@ macro_rules! setup_memory_table {
  };
 }
 
+/// The `information_schema` tables info provider.
 pub struct InformationSchemaProvider {
  catalog_name: String,
  catalog_manager: Weak<dyn CatalogManager>,
- tables: Option<HashMap<String, TableRef>>,
+ tables: HashMap<String, TableRef>,
 }
 
 impl InformationSchemaProvider {
  pub fn new(catalog_name: String, catalog_manager: Weak<dyn CatalogManager>) -> Self {
  let mut provider = Self {
  catalog_name,
  catalog_manager,
- tables: None,
+ tables: HashMap::new(),
  };
 
  provider.build_tables();
@@ -90,32 +91,33 @@ impl InformationSchemaProvider {
 
  /// Returns table names in the order of table id.
  pub fn table_names(&self) -> Vec<String> {
- let mut tables = self.tables().into_values().collect::<Vec<_>>();
+ let mut tables = self.tables.values().clone().collect::<Vec<_>>();
+
  tables.sort_by(|t1, t2| {
  t1.table_info()
  .table_id()
  .partial_cmp(&t2.table_info().table_id())
  .unwrap()
  });
-
  tables
  .into_iter()
  .map(|t| t.table_info().name.clone())
  .collect()
  }
 
  /// Returns a map of [TableRef] in information schema.
- pub fn tables(&self) -> HashMap<String, TableRef> {
- // Safety: already built in `new`.
- self.tables.clone().unwrap()
+ pub fn tables(&self) -> &HashMap<String, TableRef> {
+ assert!(!self.tables.is_empty());
+
+ &self.tables
  }
 
  /// Returns the [TableRef] by table name.
  pub fn table(&self, name: &str) -> Option<TableRef> {
- self.tables().get(name).cloned()
+ self.tables.get(name).cloned()
  }
 
- fn build_tables(&mut self) -> HashMap<String, TableRef> {
+ fn build_tables(&mut self) {
  let mut tables = HashMap::new();
  tables.insert(TABLES.to_string(), self.build_table(TABLES).unwrap());
  tables.insert(COLUMNS.to_string(), self.build_table(COLUMNS).unwrap());
@@ -125,9 +127,7 @@ impl InformationSchemaProvider {
  tables.insert((*name).to_string(), self.build_table(name).unwrap());
  }
 
- self.tables = Some(tables.clone());
-
- tables
+ self.tables = tables;
  }
 
  fn build_table(&self, name: &str) -> Option<TableRef> {

src/catalog/src/memory/manager.rs

@@ -247,7 +247,7 @@ impl MemoryCatalogManager {
  catalog,
  Arc::downgrade(self) as Weak<dyn CatalogManager>,
  );
- let information_schema = information_schema_provider.tables();
+ let information_schema = information_schema_provider.tables().clone();
  let mut catalog = HashMap::new();
  catalog.insert(INFORMATION_SCHEMA_NAME.to_string(), information_schema);
  catalog