feat(influxdb3_system_tables): expose system.tables for all databases

influxdb3_system_tables/src/lib.rs

@@ -176,7 +176,17 @@ impl AllSystemSchemaTablesProvider {
                 InfluxdbSchemaTable::new(Arc::clone(&db_schema)),
             ))),
         );
-        if db_schema.name.as_ref() == INTERNAL_DB_NAME {
+        let is_internal_database = db_schema.name.as_ref() == INTERNAL_DB_NAME;
+        // `system.tables` is available for all databases but restricts tables
+        // to that contained in the mentioned database only.
+        tables.insert(
+            TABLES_TABLE_NAME,
+            Arc::new(SystemTableProvider::new(Arc::new(TablesTable::new(
+                Arc::clone(&catalog),
+                (!is_internal_database).then_some(Arc::clone(&db_schema.name)),
+            )))),
+        );
+        if is_internal_database {
             tables.insert(
                 TOKENS_TABLE_NAME,
                 Arc::new(SystemTableProvider::new(Arc::new(TokenSystemTable::new(
@@ -202,12 +212,6 @@ impl AllSystemSchemaTablesProvider {
                     Arc::clone(&catalog),
                 )))),
             );
-            tables.insert(
-                TABLES_TABLE_NAME,
-                Arc::new(SystemTableProvider::new(Arc::new(TablesTable::new(
-                    Arc::clone(&catalog),
-                )))),
-            );
             tables.insert(
                 GENERATION_DURATIONS_TABLE_NAME,
                 Arc::new(SystemTableProvider::new(Arc::new(

influxdb3_system_tables/src/tables.rs

@@ -11,13 +11,15 @@ use iox_system_tables::IoxSystemTable;
 #[derive(Debug)]
 pub(crate) struct TablesTable {
     catalog: Arc<Catalog>,
+    database: Option<Arc<str>>,
     schema: SchemaRef,
 }
 
 impl TablesTable {
-    pub(crate) fn new(catalog: Arc<Catalog>) -> Self {
+    pub(crate) fn new(catalog: Arc<Catalog>, database: Option<Arc<str>>) -> Self {
         Self {
             catalog,
+            database,
             schema: tables_schema(),
         }
     }
@@ -52,7 +54,15 @@ impl IoxSystemTable for TablesTable {
         _filters: Option<Vec<Expr>>,
         _limit: Option<usize>,
     ) -> Result<RecordBatch, DataFusionError> {
-        let databases = self.catalog.list_db_schema();
+        let databases = if let Some(database) = &self.database {
+            let db_schema = self
+                .catalog
+                .db_schema(database)
+                .ok_or_else(|| DataFusionError::Plan(format!("database not found: {database}")))?;
+            vec![db_schema]
+        } else {
+            self.catalog.list_db_schema()
+        };
 
         // Count total tables across all databases
         let total_tables: usize = databases