refactor: new setting max_vacuum_threads (#18737)

* refactor: new setting `max_vacuum_threads`

Add new setting `max_vacuum_threads` which effect the degree of concurrency during vacuume operations.

* cargo fmt

Author: dantengsky

src/query/service/src/interpreters/interpreter_vacuum_drop_tables.rs

@@ -187,7 +187,7 @@ impl Interpreter for VacuumDropTablesInterpreter {
         let tables_count = tables.len();
 
         let handler = get_vacuum_handler();
-        let threads_nums = self.ctx.get_settings().get_max_threads()? as usize;
+        let threads_nums = self.ctx.get_settings().get_max_vacuum_threads()? as usize;
         let (files_opt, failed_tables) = handler
             .do_vacuum_drop_tables(
                 threads_nums,

src/query/settings/src/settings_default.rs

@@ -178,6 +178,13 @@ impl DefaultSettings {
                     scope: SettingScope::Both,
                     range: Some(SettingRange::Numeric(1..=1024)),
                 }),
+                ("max_vacuum_threads", DefaultSettingValue {
+                    value: UserSettingValue::UInt64(1),
+                    desc: "Sets the maximum number of threads to execute vacuum operation.",
+                    mode: SettingMode::Both,
+                    scope: SettingScope::Both,
+                    range: Some(SettingRange::Numeric(1..=3)),
+                }),
                 ("max_memory_usage", DefaultSettingValue {
                     value: UserSettingValue::UInt64(max_memory_usage),
                     desc: "Sets the maximum memory usage in bytes for processing a single query.",

src/query/settings/src/settings_getter_setter.rs

@@ -215,6 +215,10 @@ impl Settings {
         self.try_set_u64("max_threads", val)
     }
 
+    pub fn get_max_vacuum_threads(&self) -> Result<u64> {
+        self.try_get_u64("max_vacuum_threads")
+    }
+
     // Get storage_fetch_part_num.
     pub fn get_storage_fetch_part_num(&self) -> Result<u64> {
         match self.try_get_u64("storage_fetch_part_num")? {