Fix mysqlslap hang under high concurrent

docs/en/administrator-guide/config/fe_config.md

@@ -334,6 +334,14 @@ This variable is a dynamic configuration, and users can modify the configuration
 
 ### `http_backlog_num`
 
+The backlog_num for netty http server, When you enlarge this backlog_num,
+you should enlarge the value in the linux /proc/sys/net/core/somaxconn file at the same time
+
+### `mysql_nio_backlog_num`
+
+The backlog_num for mysql nio server, When you enlarge this backlog_num,
+you should enlarge the value in the linux /proc/sys/net/core/somaxconn file at the same time
+
 ### `http_port`
 
 HTTP bind port. Defaults to 8030.

docs/zh-CN/administrator-guide/config/fe_config.md

@@ -331,6 +331,12 @@ FE 的配置项有两种方式进行配置：
 ### `history_job_keep_max_second`
 
 ### `http_backlog_num`
+Doris netty http server 的backlog_num 参数，当你增大该配置时，也需要同时
+增大 Linux /proc/sys/net/core/somaxconn 文件的值 
+
+### `mysql_nio_backlog_num`
+Doris mysql nio server 的backlog_num 参数，当你增大该配置时，也需要同时
+增大 Linux /proc/sys/net/core/somaxconn 文件的值 
 
 ### `http_port`
 

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

@@ -296,11 +296,18 @@ public class Config extends ConfigBase {
 
     /**
      * The backlog_num for netty http server
-     * When you enlarge this backlog_num, you should ensure it's value larger than
-     * the linux /proc/sys/net/core/somaxconn config
+     * When you enlarge this backlog_num, you should enlarge the value in
+     * the linux /proc/sys/net/core/somaxconn file at the same time
      */
     @ConfField public static int http_backlog_num = 1024;
 
+    /**
+     * The backlog_num for mysql nio server
+     * When you enlarge this backlog_num, you should enlarge the value in
+     * the linux /proc/sys/net/core/somaxconn file at the same time
+     */
+    @ConfField public static int mysql_nio_backlog_num = 1024;
+
     /**
      * The connection timeout and socket timeout config for thrift server
      * The value for thrift_client_timeout_ms is set to be larger than zero to prevent

fe/fe-core/src/main/java/org/apache/doris/mysql/nio/NMysqlServer.java

@@ -64,7 +64,7 @@ public NMysqlServer(int port, ConnectScheduler connectScheduler) {
     public boolean start() {
         try {
             server = xnioWorker.createStreamConnectionServer(new InetSocketAddress(port),
-                    acceptListener, OptionMap.create(Options.TCP_NODELAY, true));
+                    acceptListener, OptionMap.create(Options.TCP_NODELAY, true, Options.BACKLOG, Config.mysql_nio_backlog_num));
             server.resumeAccepts();
             running = true;
             LOG.info("Open mysql server success on {}", port);