chore: bring back function set_cache_capacity

src/common/cache/src/cache.rs

@@ -72,6 +72,10 @@ pub trait Cache<K: Eq + Hash + MemSized, V: MemSized> {
 
     fn items_capacity(&self) -> u64;
 
+    fn set_bytes_capacity(&mut self, capacity: usize);
+
+    fn set_items_capacity(&mut self, capacity: usize);
+
     /// Returns the bytes size of all the key-value pairs in the cache.
     fn bytes_size(&self) -> u64;
 

src/common/cache/src/cache/lru.rs

@@ -301,6 +301,20 @@ impl<K: Eq + Hash + MemSized, V: MemSized> Cache<K, V> for LruCache<K, V> {
         self.max_items as u64
     }
 
+    fn set_bytes_capacity(&mut self, max_bytes: usize) {
+        while self.bytes > max_bytes || self.map.len() > self.max_items {
+            self.pop_by_policy();
+        }
+        self.max_bytes = max_bytes;
+    }
+
+    fn set_items_capacity(&mut self, max_items: usize) {
+        while self.bytes > self.max_bytes || self.map.len() > max_items {
+            self.pop_by_policy();
+        }
+        self.max_items = max_items;
+    }
+
     /// Returns the bytes size of all the key-value pairs in the cache.
     fn bytes_size(&self) -> u64 {
         self.bytes as u64

src/query/service/src/interpreters/access/privilege_access.rs

@@ -60,7 +60,7 @@ enum ObjectId {
 }
 
 // table functions that need `Super` privilege
-const SYSTEM_TABLE_FUNCTIONS: [&str; 1] = ["fuse_amend"];
+const SYSTEM_TABLE_FUNCTIONS: [&str; 2] = ["fuse_amend", "set_cache_capacity"];
 
 impl PrivilegeAccess {
     pub fn create(ctx: Arc<QueryContext>) -> Box<dyn AccessChecker> {

src/query/service/src/table_functions/table_function_factory.rs

@@ -27,6 +27,7 @@ use databend_common_storages_fuse::table_functions::FuseEncodingFunc;
 use databend_common_storages_fuse::table_functions::FuseStatisticsFunc;
 use databend_common_storages_fuse::table_functions::FuseTimeTravelSizeFunc;
 use databend_common_storages_fuse::table_functions::FuseVacuumTemporaryTable;
+use databend_common_storages_fuse::table_functions::SetCacheCapacity;
 use databend_common_storages_fuse::table_functions::TableFunctionTemplate;
 use databend_common_storages_stream::stream_status_table_func::StreamStatusTable;
 use databend_storages_common_table_meta::table_id_ranges::SYS_TBL_FUC_ID_END;
@@ -138,6 +139,14 @@ impl TableFunctionFactory {
             ),
         );
 
+        creators.insert(
+            "set_cache_capacity".to_string(),
+            (
+                next_id(),
+                Arc::new(TableFunctionTemplate::<SetCacheCapacity>::create),
+            ),
+        );
+
         creators.insert(
             "fuse_segment".to_string(),
             (