[fix](http) throw RejectedExecutionException to prevent http hanging by Future (#29607)

fe/fe-common/src/main/java/org/apache/doris/common/Config.java

@@ -2395,4 +2395,16 @@ public class Config extends ConfigBase {
     public static boolean enable_profile_when_analyze = false;
     @ConfField(mutable = true)
     public static boolean enable_collect_internal_query_profile = false;
+
+    @ConfField(mutable = false, masterOnly = false, description = {
+        "http请求处理/api/query中sql任务的最大线程池。",
+        "The max number work threads of http sql submitter."
+    })
+    public static int http_sql_submitter_max_worker_threads = 2;
+
+    @ConfField(mutable = false, masterOnly = false, description = {
+        "http请求处理/api/upload任务的最大线程池。",
+        "The max number work threads of http upload submitter."
+    })
+    public static int http_load_submitter_max_worker_threads = 2;
 }